Changeset - 17fe648a8934
[Not reviewed]
0 11 0
MH - 4 years ago 2021-04-29 14:42:37
contact@maxhenger.nl
Partial reimplementation of compiler and TypeTable

Every type symbol and its possible polymorphic variables are now
parsed up front and put in the SymbolTable, doing away with the
complicated and error-prone NamespacedIdentifier. Still pending
changes to parts of the compiler and the runtime, so not working
at the moment.
11 files changed with 559 insertions and 1052 deletions:
0 comments (0 inline, 0 general)
src/collections/scoped_buffer.rs
Show inline comments
 
/// scoped_buffer.rs
 
///
 
/// Solves the common pattern where we are performing some kind of recursive
 
/// pattern while using a temporary buffer. At the start, or during the
 
/// procedure, we push stuff into the buffer. At the end we take out what we
 
/// have put in.
 
///
 
/// It is unsafe because we're using pointers to take care of borrowing rules.
 
/// The correctness of use is checked in debug mode.
 
/// It is unsafe because we're using pointers to circumvent borrowing rules in
 
/// the name of code cleanliness. The correctness of use is checked in debug
 
/// mode.
 

	
 
/// The buffer itself. This struct should be the shared buffer. The type `T` is
 
/// intentionally `Copy` such that it can be copied out and the underlying
 
/// container can be truncated.
 
pub(crate) struct ScopedBuffer<T: Sized + Copy> {
 
    pub inner: Vec<T>,
 
}
 

	
 
/// A section of the buffer. Keeps track of where we started the section. When
 
/// done with the section one must call `into_vec` or `forget` to remove the
 
/// section from the underlying buffer.
 
pub(crate) struct ScopedSection<T: Sized + Copy> {
 
    inner: *mut Vec<T>,
 
    start_size: u32,
 
    #[cfg(debug_assertions)] cur_size: u32,
 
}
 

	
 
impl<T: Sized + Copy> ScopedBuffer<T> {
 
    pub(crate) fn new_reserved(capacity: usize) -> Self {
 
        Self{ inner: Vec::with_capacity(capacity) }
 
    }
 

	
 
    pub(crate) fn start_section(&mut self) -> ScopedSection<T> {
 
        let start_size = self.inner.len() as u32;
 
        ScopedSection{
 
            inner: &mut self.inner,
 
            start_size,
 
            cur_size: start_size
 
        }
 
    }
 
}
 

	
 
#[cfg(debug_assertions)]
 
impl<T: Sized + Copy> Drop for ScopedBuffer<T> {
 
    fn drop(&mut self) {
 
        // Make sure that everyone cleaned up the buffer neatly
 
        debug_assert!(self.inner.is_empty(), "dropped non-empty scoped buffer");
 
    }
 
}
 

	
 
impl<T: Sized + Copy> ScopedSection<T> {
 
    #[inline]
 
    pub(crate) fn push(&mut self, value: T) {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert!_eq(vec.len(), self.cur_size as usize, "trying to push onto section, but size is larger than expected");
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to push onto section, but size is larger than expected");
 
        vec.push(value);
 
        if cfg!(debug_assertions) { self.cur_size += 1; }
 
    }
 

	
 
    pub(crate) fn len(&self) -> usize {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to get section length, but size is larger than expected");
 
        return vec.len() - self.start_size;
 
    }
 

	
 
    #[inline]
 
    pub(crate) fn forget(self) {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to forget section, but size is larger than expected");
 
        vec.truncate(self.start_size as usize);
 
    }
 

	
 
    #[inline]
 
    pub(crate) fn into_vec(self) -> Vec<T> {
 
        let vec = unsafe{&mut *self.inner};
 
        debug_assert_eq!(vec.len(), self.cur_size as usize, "trying to turn section into vec, but size is larger than expected");
 
        let section = Vec::from(&vec[self.start_size as usize..]);
 
        vec.truncate(self.start_size as usize);
 
        section
 
    }
 
}
 

	
 
impl<T: Sized + Copy> std::ops::Index<usize> for ScopedSection<T> {
 
    type Output = T;
 

	
 
    fn index(&self, idx: usize) -> &Self::Output {
 
        let vec = unsafe{&*self.inner};
 
        return vec[self.start_size as usize + idx]
 
    }
 
}
 

	
 
#[cfg(debug_assertions)]
 
impl<T: Sized + Copy> Drop for ScopedBuffer<T> {
 
    fn drop(&mut self) {
 
        // Make sure that the data was actually taken out of the scoped section
 
        let vec = unsafe{&*self.inner};
 
        debug_assert_eq!(vec.len(), self.start_size as usize);
 
    }
 
}
 
\ No newline at end of file
src/protocol/ast.rs
Show inline comments
 
// TODO: @cleanup, rigorous cleanup of dead code and silly object-oriented
 
//  trait impls where I deem them unfit.
 

	
 
use std::fmt;
 
use std::fmt::{Debug, Display, Formatter};
 
use std::ops::{Index, IndexMut};
 

	
 
use super::arena::{Arena, Id};
 
use crate::collections::StringRef;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::input_source2::{InputPosition2, InputSpan};
 

	
 
/// Global limits to the AST, should be checked by lexer and parser. Some are
 
/// arbitrary
 
const MAX_LEVEL: usize = 128;
 
const MAX_NAMESPACES: usize = 64;
 

	
 
/// Helper macro that defines a type alias for a AST element ID. In this case 
 
/// only used to alias the `Id<T>` types.
 
macro_rules! define_aliased_ast_id {
 
    // Variant where we just defined the alias, without any indexing
 
    ($name:ident, $parent:ty) => {
 
        pub type $name = $parent;
 
    };
 
    // Variant where we define the type, and the Index and IndexMut traits
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $indexed_arena:ident)
 
    ) => {
 
        define_aliased_ast_id!($name, $parent);
 
        impl Index<$name> for Heap {
 
            type Output = $indexed_type;
 
            fn index(&self, index: $name) -> &Self::Output {
 
                &self.$indexed_arena[index]
 
            }
 
        }
 

	
 
        impl IndexMut<$name> for Heap {
 
            fn index_mut(&mut self, index: $name) -> &mut Self::Output {
 
                &mut self.$indexed_arena[index]
 
            }
 
        }
 
    };
 
    // Variant where we define type, Index(Mut) traits and an allocation function
 
    (
 
        $name:ident, $parent:ty,
 
        index($indexed_type:ty, $indexed_arena:ident),
 
        alloc($fn_name:ident)
 
    ) => {
 
        define_aliased_ast_id!($name, $parent, index($indexed_type, $indexed_arena));
 
        impl Heap {
 
            pub fn $fn_name(&mut self, f: impl FnOnce($name) -> $indexed_type) -> $name {
 
                self.$indexed_arena.alloc_with_id(|id| f(id))
 
            }
 
        }
 
    };
 
}
 

	
 
/// Helper macro that defines a wrapper type for a particular variant of an AST
 
/// element ID. Only used to define single-wrapping IDs.
 
macro_rules! define_new_ast_id {
 
    // Variant where we just defined the new type, without any indexing
 
    ($name:ident, $parent:ty) => {
 
        #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 
        pub struct $name (pub(crate) $parent);
 

	
 
        impl $name {
 
            pub(crate) fn new_invalid() -> Self     { Self($parent::new_invalid()) }
 
            pub(crate) fn is_invalid(&self) -> bool { self.0.is_invalid() }
 
            pub fn upcast(self) -> $parent          { self.0 }
 
        }
 
    };
 
    // Variant where we define the type, and the Index and IndexMut traits
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $wrapper_type:path, $indexed_arena:ident)
 
    ) => {
 
        define_new_ast_id!($name, $parent);
 
        impl Index<$name> for Heap {
 
            type Output = $indexed_type;
 
            fn index(&self, index: $name) -> &Self::Output {
 
                if let $wrapper_type(v) = &self.$indexed_arena[index.0] {
 
                    v
 
                } else {
 
                    unreachable!()
 
                }
 
            }
 
        }
 

	
 
        impl IndexMut<$name> for Heap {
 
            fn index_mut(&mut self, index: $name) -> &mut Self::Output {
 
                if let $wrapper_type(v) = &mut self.$indexed_arena[index.0] {
 
                    v
 
                } else {
 
                    unreachable!()
 
                }
 
            }
 
        }
 
    };
 
    // Variant where we define the type, the Index and IndexMut traits, and an allocation function
 
    (
 
        $name:ident, $parent:ty, 
 
        index($indexed_type:ty, $wrapper_type:path, $indexed_arena:ident),
 
        alloc($fn_name:ident)
 
    ) => {
 
        define_new_ast_id!($name, $parent, index($indexed_type, $wrapper_type, $indexed_arena));
 
        impl Heap {
 
            pub fn $fn_name(&mut self, f: impl FnOnce($name) -> $indexed_type) -> $name {
 
                $name(
 
                    self.$indexed_arena.alloc_with_id(|id| {
 
                        $wrapper_type(f($name(id)))
 
                    })
 
                )
 
            }
 
        }
 
    }
 
}
 

	
 
define_aliased_ast_id!(RootId, Id<Root>, index(Root, protocol_descriptions), alloc(alloc_protocol_description));
 
define_aliased_ast_id!(PragmaId, Id<Pragma>, index(Pragma, pragmas), alloc(alloc_pragma));
 
define_aliased_ast_id!(ImportId, Id<Import>, index(Import, imports), alloc(alloc_import));
 
define_aliased_ast_id!(ParserTypeId, Id<ParserType>, index(ParserType, parser_types), alloc(alloc_parser_type));
 

	
 
define_aliased_ast_id!(VariableId, Id<Variable>, index(Variable, variables));
 
define_new_ast_id!(ParameterId, VariableId, index(Parameter, Variable::Parameter, variables), alloc(alloc_parameter));
 
define_new_ast_id!(LocalId, VariableId, index(Local, Variable::Local, variables), alloc(alloc_local));
 

	
 
define_aliased_ast_id!(DefinitionId, Id<Definition>, index(Definition, definitions));
 
define_new_ast_id!(StructDefinitionId, DefinitionId, index(StructDefinition, Definition::Struct, definitions), alloc(alloc_struct_definition));
 
define_new_ast_id!(EnumDefinitionId, DefinitionId, index(EnumDefinition, Definition::Enum, definitions), alloc(alloc_enum_definition));
 
define_new_ast_id!(UnionDefinitionId, DefinitionId, index(UnionDefinition, Definition::Union, definitions), alloc(alloc_union_definition));
 
define_new_ast_id!(ComponentDefinitionId, DefinitionId, index(ComponentDefinition, Definition::Component, definitions), alloc(alloc_component_definition));
 
define_new_ast_id!(FunctionDefinitionId, DefinitionId, index(FunctionDefinition, Definition::Function, definitions), alloc(alloc_function_definition));
 

	
 
define_aliased_ast_id!(StatementId, Id<Statement>, index(Statement, statements));
 
define_new_ast_id!(BlockStatementId, StatementId, index(BlockStatement, Statement::Block, statements), alloc(alloc_block_statement));
 
define_new_ast_id!(LocalStatementId, StatementId, index(LocalStatement, Statement::Local, statements), alloc(alloc_local_statement));
 
define_new_ast_id!(MemoryStatementId, LocalStatementId);
 
define_new_ast_id!(ChannelStatementId, LocalStatementId);
 
define_new_ast_id!(LabeledStatementId, StatementId, index(LabeledStatement, Statement::Labeled, statements), alloc(alloc_labeled_statement));
 
define_new_ast_id!(IfStatementId, StatementId, index(IfStatement, Statement::If, statements), alloc(alloc_if_statement));
 
define_new_ast_id!(EndIfStatementId, StatementId, index(EndIfStatement, Statement::EndIf, statements), alloc(alloc_end_if_statement));
 
define_new_ast_id!(WhileStatementId, StatementId, index(WhileStatement, Statement::While, statements), alloc(alloc_while_statement));
 
define_new_ast_id!(EndWhileStatementId, StatementId, index(EndWhileStatement, Statement::EndWhile, statements), alloc(alloc_end_while_statement));
 
define_new_ast_id!(BreakStatementId, StatementId, index(BreakStatement, Statement::Break, statements), alloc(alloc_break_statement));
 
define_new_ast_id!(ContinueStatementId, StatementId, index(ContinueStatement, Statement::Continue, statements), alloc(alloc_continue_statement));
 
define_new_ast_id!(SynchronousStatementId, StatementId, index(SynchronousStatement, Statement::Synchronous, statements), alloc(alloc_synchronous_statement));
 
define_new_ast_id!(EndSynchronousStatementId, StatementId, index(EndSynchronousStatement, Statement::EndSynchronous, statements), alloc(alloc_end_synchronous_statement));
 
define_new_ast_id!(ReturnStatementId, StatementId, index(ReturnStatement, Statement::Return, statements), alloc(alloc_return_statement));
 
define_new_ast_id!(AssertStatementId, StatementId, index(AssertStatement, Statement::Assert, statements), alloc(alloc_assert_statement));
 
define_new_ast_id!(GotoStatementId, StatementId, index(GotoStatement, Statement::Goto, statements), alloc(alloc_goto_statement));
 
define_new_ast_id!(NewStatementId, StatementId, index(NewStatement, Statement::New, statements), alloc(alloc_new_statement));
 
define_new_ast_id!(ExpressionStatementId, StatementId, index(ExpressionStatement, Statement::Expression, statements), alloc(alloc_expression_statement));
 

	
 
define_aliased_ast_id!(ExpressionId, Id<Expression>, index(Expression, expressions));
 
define_new_ast_id!(AssignmentExpressionId, ExpressionId, index(AssignmentExpression, Expression::Assignment, expressions), alloc(alloc_assignment_expression));
 
define_new_ast_id!(BindingExpressionId, ExpressionId, index(BindingExpression, Expression::Binding, expressions), alloc(alloc_binding_expression));
 
define_new_ast_id!(ConditionalExpressionId, ExpressionId, index(ConditionalExpression, Expression::Conditional, expressions), alloc(alloc_conditional_expression));
 
define_new_ast_id!(BinaryExpressionId, ExpressionId, index(BinaryExpression, Expression::Binary, expressions), alloc(alloc_binary_expression));
 
define_new_ast_id!(UnaryExpressionId, ExpressionId, index(UnaryExpression, Expression::Unary, expressions), alloc(alloc_unary_expression));
 
define_new_ast_id!(IndexingExpressionId, ExpressionId, index(IndexingExpression, Expression::Indexing, expressions), alloc(alloc_indexing_expression));
 
define_new_ast_id!(SlicingExpressionId, ExpressionId, index(SlicingExpression, Expression::Slicing, expressions), alloc(alloc_slicing_expression));
 
define_new_ast_id!(SelectExpressionId, ExpressionId, index(SelectExpression, Expression::Select, expressions), alloc(alloc_select_expression));
 
define_new_ast_id!(LiteralExpressionId, ExpressionId, index(LiteralExpression, Expression::Literal, expressions), alloc(alloc_literal_expression));
 
define_new_ast_id!(CallExpressionId, ExpressionId, index(CallExpression, Expression::Call, expressions), alloc(alloc_call_expression));
 
define_new_ast_id!(VariableExpressionId, ExpressionId, index(VariableExpression, Expression::Variable, expressions), alloc(alloc_variable_expression));
 

	
 
// TODO: @cleanup - pub qualifiers can be removed once done
 
#[derive(Debug)]
 
pub struct Heap {
 
    // Root arena, contains the entry point for different modules. Each root
 
    // contains lists of IDs that correspond to the other arenas.
 
    pub(crate) protocol_descriptions: Arena<Root>,
 
    // Contents of a file, these are the elements the `Root` elements refer to
 
    pragmas: Arena<Pragma>,
 
    pub(crate) imports: Arena<Import>,
 
    pub(crate) parser_types: Arena<ParserType>,
 
    pub(crate) variables: Arena<Variable>,
 
    pub(crate) definitions: Arena<Definition>,
 
    pub(crate) statements: Arena<Statement>,
 
    pub(crate) expressions: Arena<Expression>,
 
}
 

	
 
impl Heap {
 
    pub fn new() -> Heap {
 
        Heap {
 
            // string_alloc: StringAllocator::new(),
 
            protocol_descriptions: Arena::new(),
 
            pragmas: Arena::new(),
 
            imports: Arena::new(),
 
            parser_types: Arena::new(),
 
            variables: Arena::new(),
 
            definitions: Arena::new(),
 
            statements: Arena::new(),
 
            expressions: Arena::new(),
 
        }
 
    }
 
    pub fn alloc_memory_statement(
 
        &mut self,
 
        f: impl FnOnce(MemoryStatementId) -> MemoryStatement,
 
    ) -> MemoryStatementId {
 
        MemoryStatementId(LocalStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::Local(LocalStatement::Memory(
 
                f(MemoryStatementId(LocalStatementId(id)))
 
            ))
 
        })))
 
    }
 
    pub fn alloc_channel_statement(
 
        &mut self,
 
        f: impl FnOnce(ChannelStatementId) -> ChannelStatement,
 
    ) -> ChannelStatementId {
 
        ChannelStatementId(LocalStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::Local(LocalStatement::Channel(
 
                f(ChannelStatementId(LocalStatementId(id)))
 
            ))
 
        })))
 
    }
 
}
 

	
 
impl Index<MemoryStatementId> for Heap {
 
    type Output = MemoryStatement;
 
    fn index(&self, index: MemoryStatementId) -> &Self::Output {
 
        &self.statements[index.0.0].as_memory()
 
    }
 
}
 

	
 
impl Index<ChannelStatementId> for Heap {
 
    type Output = ChannelStatement;
 
    fn index(&self, index: ChannelStatementId) -> &Self::Output {
 
        &self.statements[index.0.0].as_channel()
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Root {
 
    pub this: RootId,
 
    // Phase 1: parser
 
    // pub position: InputPosition,
 
    pub pragmas: Vec<PragmaId>,
 
    pub imports: Vec<ImportId>,
 
    pub definitions: Vec<DefinitionId>,
 
}
 

	
 
impl Root {
 
    pub fn get_definition_ident(&self, h: &Heap, id: &[u8]) -> Option<DefinitionId> {
 
        for &def in self.definitions.iter() {
 
            if h[def].identifier().value == id {
 
                return Some(def);
 
            }
 
        }
 
        None
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Pragma {
 
    Version(PragmaVersion),
 
    Module(PragmaModule),
 
}
 

	
 
impl Pragma {
 
    pub(crate) fn as_module(&self) -> &PragmaModule {
 
        match self {
 
            Pragma::Module(pragma) => pragma,
 
            _ => unreachable!("Tried to obtain {:?} as PragmaModule", self),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct PragmaVersion {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of full pragma
 
    pub version: u64,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct PragmaModule {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of full pragma
 
    pub value: Identifier,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Import {
 
    Module(ImportModule),
 
    Symbols(ImportSymbols)
 
}
 

	
 
impl Import {
 
    pub(crate) fn span(&self) -> InputSpan {
 
        match self {
 
            Import::Module(v) => v.span,
 
            Import::Symbols(v) => v.span,
 
        }
 
    }
 

	
 
    pub(crate) fn as_module(&self) -> &ImportModule {
 
        match self {
 
            Import::Module(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportModule'")
 
        }
 
    }
 
    pub(crate) fn as_symbols(&self) -> &ImportSymbols {
 
        match self {
 
            Import::Symbols(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportSymbols'")
 
        }
 
    }
 
    pub(crate) fn as_symbols_mut(&mut self) -> &mut ImportSymbols {
 
        match self {
 
            Import::Symbols(m) => m,
 
            _ => unreachable!("Unable to cast 'Import' to 'ImportSymbols'")
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ImportModule {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub module: Identifier,
 
    pub alias: Identifier,
 
    pub module_id: RootId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct AliasedSymbol {
 
    pub name: Identifier,
 
    pub alias: Option<Identifier>,
 
    pub definition_id: DefinitionId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ImportSymbols {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub module: Identifier,
 
    pub module_id: RootId,
 
    pub symbols: Vec<AliasedSymbol>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Identifier {
 
    pub span: InputSpan,
 
    pub value: StringRef<'static>,
 
}
 

	
 
impl PartialEq for Identifier {
 
    fn eq(&self, other: &Self) -> bool {
 
        return self.value == other.value
 
    }
 
}
 

	
 
impl Display for Identifier {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
 
        // A source identifier is in ASCII range.
 
        write!(f, "{}", String::from_utf8_lossy(&self.value))
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum NamespacedIdentifierPart {
 
    // Regular identifier
 
    Identifier{start: u16, end: u16},
 
    // Polyargs associated with a preceding identifier
 
    PolyArgs{start: u16, end: u16},
 
}
 

	
 
impl NamespacedIdentifierPart {
 
    pub(crate) fn is_identifier(&self) -> bool {
 
        match self {
 
            NamespacedIdentifierPart::Identifier{..} => true,
 
            NamespacedIdentifierPart::PolyArgs{..} => false,
 
        }
 
    }
 

	
 
    pub(crate) fn as_identifier(&self) -> (u16, u16) {
 
        match self {
 
            NamespacedIdentifierPart::Identifier{start, end} => (*start, *end),
 
            NamespacedIdentifierPart::PolyArgs{..} => {
 
                unreachable!("Tried to obtain {:?} as Identifier", self);
 
            }
 
        }
 
    }
 

	
 
    pub(crate) fn as_poly_args(&self) -> (u16, u16) {
 
        match self {
 
            NamespacedIdentifierPart::PolyArgs{start, end} => (*start, *end),
 
            NamespacedIdentifierPart::Identifier{..} => {
 
                unreachable!("Tried to obtain {:?} as PolyArgs", self)
 
            }
 
        }
 
    }
 
}
 

	
 
/// An identifier with optional namespaces and polymorphic variables. Note that 
 
/// we allow each identifier to be followed by polymorphic arguments during the 
 
/// parsing phase (e.g. Foo<A,B>::Bar<C,D>::Qux). But in our current language 
 
/// implementation we can only have valid namespaced identifier that contain one
 
/// set of polymorphic arguments at the appropriate position.
 
/// TODO: @tokens Reimplement/rename once we have a tokenizer
 
#[derive(Debug, Clone)]
 
pub struct NamespacedIdentifier {
 
    pub position: InputPosition,
 
    pub value: Vec<u8>, // Full name as it resides in the input source
 
    pub poly_args: Vec<ParserTypeId>, // All poly args littered throughout the namespaced identifier
 
    pub parts: Vec<NamespacedIdentifierPart>, // Indices into value/poly_args
 
}
 

	
 
impl NamespacedIdentifier {
 
    /// Returns the identifier value without any of the specific polymorphic
 
    /// arguments.
 
    pub fn strip_poly_args(&self) -> Vec<u8> {
 
        debug_assert!(!self.parts.is_empty() && self.parts[0].is_identifier());
 

	
 
        let mut result = Vec::with_capacity(self.value.len());
 
        let mut iter = self.iter();
 
        let (first_ident, _) = iter.next().unwrap();
 
        result.extend(first_ident);
 

	
 
        for (ident, _) in iter.next() {
 
            result.push(b':');
 
            result.push(b':');
 
            result.extend(ident);
 
        }
 

	
 
        result
 
    }
 

	
 
    /// Returns an iterator of the elements in the namespaced identifier
 
    pub fn iter(&self) -> NamespacedIdentifierIter {
 
        return NamespacedIdentifierIter{
 
            identifier: self,
 
            element_idx: 0
 
        }
 
    }
 

	
 
    pub fn get_poly_args(&self) -> Option<&[ParserTypeId]> {
 
        let has_poly_args = self.parts.iter().any(|v| !v.is_identifier());
 
        if has_poly_args {
 
            Some(&self.poly_args)
 
        } else {
 
            None
 
        }
 
    }
 

	
 
    // Check if two namespaced identifiers match eachother when not considering
 
    // the polymorphic arguments
 
    pub fn matches_namespaced_identifier(&self, other: &Self) -> bool {
 
        let mut iter_self = self.iter();
 
        let mut iter_other = other.iter();
 

	
 
        loop {
 
            let val_self = iter_self.next();
 
            let val_other = iter_other.next();
 
            if val_self.is_some() != val_other.is_some() {
 
                // One is longer than the other
 
                return false;
 
            }
 
            if val_self.is_none() {
 
                // Both are none
 
                return true;
 
            }
 

	
 
            // Both are something
 
            let (val_self, _) = val_self.unwrap();
 
            let (val_other, _) = val_other.unwrap();
 
            if val_self != val_other { return false; }
 
        }
 
    }
 

	
 
    // Check if the namespaced identifier matches an identifier when not 
 
    // considering the polymorphic arguments
 
    pub fn matches_identifier(&self, other: &Identifier) -> bool {
 
        let mut iter = self.iter();
 
        let (first_ident, _) = iter.next().unwrap();
 
        if first_ident != other.value { 
 
            return false;
 
        }
 

	
 
        if iter.next().is_some() {
 
            return false;
 
        }
 

	
 
        return true;
 
    }
 
}
 

	
 
/// Iterator over elements of the namespaced identifier. The element index will
 
/// only ever be at the start of an identifier element.
 
#[derive(Debug)]
 
pub struct NamespacedIdentifierIter<'a> {
 
    identifier: &'a NamespacedIdentifier,
 
    element_idx: usize,
 
}
 

	
 
impl<'a> Iterator for NamespacedIdentifierIter<'a> {
 
    type Item = (&'a [u8], Option<&'a [ParserTypeId]>);
 
    fn next(&mut self) -> Option<Self::Item> {
 
        match self.get(self.element_idx) {
 
            Some((ident, poly)) => {
 
                self.element_idx += 1;
 
                if poly.is_some() {
 
                    self.element_idx += 1;
 
                }
 
                Some((ident, poly))
 
            },
 
            None => None
 
        }
 
    }
 
}
 

	
 
impl<'a> NamespacedIdentifierIter<'a> {
 
    /// Returns number of parts iterated over, may not correspond to number of
 
    /// times one called `next()` because returning an identifier with 
 
    /// polymorphic arguments increments the internal counter by 2.
 
    pub fn num_returned(&self) -> usize {
 
        return self.element_idx;
 
    }
 

	
 
    pub fn num_remaining(&self) -> usize {
 
        return self.identifier.parts.len() - self.element_idx;
 
    }
 

	
 
    pub fn returned_section(&self) -> &[u8] {
 
        if self.element_idx == 0 { return &self.identifier.value[0..0]; }
 

	
 
        let last_idx = match &self.identifier.parts[self.element_idx - 1] {
 
            NamespacedIdentifierPart::Identifier{end, ..} => *end,
 
            NamespacedIdentifierPart::PolyArgs{end, ..} => *end,
 
        };
 

	
 
        return &self.identifier.value[..last_idx as usize];
 
    }
 

	
 
    /// Returns a specific element from the namespaced identifier
 
    pub fn get(&self, idx: usize) -> Option<<Self as Iterator>::Item> {
 
        if idx >= self.identifier.parts.len() { 
 
            return None 
 
        }
 

	
 
        let cur_part = &self.identifier.parts[idx];
 
        let next_part = self.identifier.parts.get(idx + 1);
 

	
 
        let (ident_start, ident_end) = cur_part.as_identifier();
 
        let poly_slice = match next_part {
 
            Some(part) => match part {
 
                NamespacedIdentifierPart::Identifier{..} => None,
 
                NamespacedIdentifierPart::PolyArgs{start, end} => Some(
 
                    &self.identifier.poly_args[*start as usize..*end as usize]
 
                ),
 
            },
 
            None => None
 
        };
 

	
 
        Some((
 
            &self.identifier.value[ident_start as usize..ident_end as usize],
 
            poly_slice
 
        ))
 
    }
 

	
 
    /// Returns the previously returend index into the parts array of the 
 
    /// identifier.
 
    pub fn prev_idx(&self) -> Option<usize> {
 
        if self.element_idx == 0 { 
 
            return None;
 
        };
 
        
 
        if self.identifier.parts[self.element_idx - 1].is_identifier() { 
 
            return Some(self.element_idx - 1);
 
        }
 

	
 
        // Previous part had polymorphic arguments, so the one before that must
 
        // be an identifier (if well formed)
 
        debug_assert!(self.element_idx >= 2 && self.identifier.parts[self.element_idx - 2].is_identifier());
 
        return Some(self.element_idx - 2)
 
    }
 

	
 
    /// Returns the previously returned result from `next()`
 
    pub fn prev(&self) -> Option<<Self as Iterator>::Item> {
 
        match self.prev_idx() {
 
            None => None,
 
            Some(idx) => self.get(idx)
 
        }
 
        write!(f, "{}", self.value.as_str())
 
    }
 
}
 

	
 
#[derive(Debug, Clone, PartialOrd, Ord)]
 
pub enum ParserTypeVariant {
 
    // Basic builtin
 
    Message,
 
    Bool,
 
    UInt8, UInt16, UInt32, UInt64,
 
    SInt8, SInt16, SInt32, SInt64,
 
    Character, String,
 
    // Literals (need to get concrete builtin type during typechecking)
 
    IntegerLiteral,
 
    // Marker for inference
 
    Inferred,
 
    // Builtins expecting one subsequent type
 
    Array,
 
    Input,
 
    Output,
 
    // User-defined types
 
    PolymorphicArgument(DefinitionId, usize), // usize = index into polymorphic variables
 
    Definition(DefinitionId, usize), // usize = number of following subtypes
 
}
 

	
 
impl ParserTypeVariant {
 
    pub(crate) fn num_embedded(&self) -> usize {
 
        match self {
 
            x if *x <= ParserTypeVariant::Inferred => 0,
 
            x if *x <= ParserTypeVariant::Output => 1,
 
            ParserTypeVariant::PolymorphicArgument(_, _) => 0,
 
            ParserTypeVariant::Definition(_, num) => num,
 
            _ => { debug_assert!(false); 0 },
 
        }
 
    }
 
}
 

	
 
pub struct ParserTypeElement {
 
    // TODO: @cleanup, do we ever need the span of a user-defined type after
 
    //  constructing it?
 
    pub full_span: InputSpan, // full span of type, including any polymorphic arguments
 
    pub variant: ParserTypeVariant,
 
}
 

	
 
/// ParserType is a specification of a type during the parsing phase and initial
 
/// linker/validator phase of the compilation process. These types may be
 
/// (partially) inferred or represent literals (e.g. a integer whose bytesize is
 
/// not yet determined).
 
#[derive(Debug, Clone)]
 
pub struct ParserType {
 
    pub elements: Vec<ParserTypeElement>
 
}
 

	
 
/// SymbolicParserType is the specification of a symbolic type. During the
 
/// parsing phase we will only store the identifier of the type. During the
 
/// validation phase we will determine whether it refers to a user-defined type,
 
/// or a polymorphic argument. After the validation phase it may still be the
 
/// case that the resulting `variant` will not pass the typechecker.
 
#[derive(Debug, Clone)]
 
pub struct SymbolicParserType {
 
    // Phase 1: parser
 
    pub identifier: NamespacedIdentifier,
 
    // Phase 2: validation/linking (for types in function/component bodies) and
 
    //  type table construction (for embedded types of structs/unions)
 
    pub poly_args2: Vec<ParserTypeId>, // taken from identifier or inferred
 
    pub variant: Option<SymbolicParserTypeVariant>
 
}
 

	
 
/// Specifies whether the symbolic type points to an actual user-defined type,
 
/// or whether it points to a polymorphic argument within the definition (e.g.
 
/// a defined variable `T var` within a function `int func<T>()`
 
#[derive(Debug, Clone)]
 
pub enum SymbolicParserTypeVariant {
 
    Definition(DefinitionId),
 
    // TODO: figure out if I need the DefinitionId here
 
    PolyArg(DefinitionId, usize), // index of polyarg in the definition
 
}
 

	
 
/// ConcreteType is the representation of a type after resolving symbolic types
 
/// and performing type inference
 
#[derive(Debug, Clone, Copy, Eq, PartialEq)]
 
pub enum ConcreteTypePart {
 
    // Markers for the use of polymorphic types within a procedure's body that
 
    // refer to polymorphic variables on the procedure's definition. Different
 
    // from markers in the `InferenceType`, these will not contain nested types.
 
    Marker(usize),
 
    // Special types (cannot be explicitly constructed by the programmer)
 
    Void,
 
    // Builtin types without nested types
 
    Message,
 
    Bool,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    String,
 
    // Builtin types with one nested type
 
    Array,
 
    Slice,
 
    Input,
 
    Output,
 
    // User defined type with any number of nested types
 
    Instance(DefinitionId, usize),
 
}
 

	
 
#[derive(Debug, Clone, Eq, PartialEq)]
 
pub struct ConcreteType {
 
    pub(crate) parts: Vec<ConcreteTypePart>
 
}
 

	
 
impl Default for ConcreteType {
 
    fn default() -> Self {
 
        Self{ parts: Vec::new() }
 
    }
 
}
 

	
 
impl ConcreteType {
 
    pub(crate) fn has_marker(&self) -> bool {
 
        self.parts
 
            .iter()
 
            .any(|p| {
 
                if let ConcreteTypePart::Marker(_) = p { true } else { false }
 
            })
 
    }
 
}
 

	
 
// TODO: Remove at some point
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum PrimitiveType {
 
    Unassigned,
 
    Input,
 
    Output,
 
    Message,
 
    Boolean,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub struct Type {
 
    pub primitive: PrimitiveType,
 
    pub array: bool,
 
}
 

	
 
#[allow(dead_code)]
 
impl Type {
 
    pub const UNASSIGNED: Type = Type { primitive: PrimitiveType::Unassigned, array: false };
 

	
 
    pub const INPUT: Type = Type { primitive: PrimitiveType::Input, array: false };
 
    pub const OUTPUT: Type = Type { primitive: PrimitiveType::Output, array: false };
 
    pub const MESSAGE: Type = Type { primitive: PrimitiveType::Message, array: false };
 
    pub const BOOLEAN: Type = Type { primitive: PrimitiveType::Boolean, array: false };
 
    pub const BYTE: Type = Type { primitive: PrimitiveType::Byte, array: false };
 
    pub const SHORT: Type = Type { primitive: PrimitiveType::Short, array: false };
 
    pub const INT: Type = Type { primitive: PrimitiveType::Int, array: false };
 
    pub const LONG: Type = Type { primitive: PrimitiveType::Long, array: false };
 

	
 
    pub const INPUT_ARRAY: Type = Type { primitive: PrimitiveType::Input, array: true };
 
    pub const OUTPUT_ARRAY: Type = Type { primitive: PrimitiveType::Output, array: true };
 
    pub const MESSAGE_ARRAY: Type = Type { primitive: PrimitiveType::Message, array: true };
 
    pub const BOOLEAN_ARRAY: Type = Type { primitive: PrimitiveType::Boolean, array: true };
 
    pub const BYTE_ARRAY: Type = Type { primitive: PrimitiveType::Byte, array: true };
 
    pub const SHORT_ARRAY: Type = Type { primitive: PrimitiveType::Short, array: true };
 
    pub const INT_ARRAY: Type = Type { primitive: PrimitiveType::Int, array: true };
 
    pub const LONG_ARRAY: Type = Type { primitive: PrimitiveType::Long, array: true };
 
}
 

	
 
impl Display for Type {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
 
        match &self.primitive {
 
            PrimitiveType::Unassigned => {
 
                write!(f, "unassigned")?;
 
            }
 
            PrimitiveType::Input => {
 
                write!(f, "in")?;
 
            }
 
            PrimitiveType::Output => {
 
                write!(f, "out")?;
 
            }
 
            PrimitiveType::Message => {
 
                write!(f, "msg")?;
 
            }
 
            PrimitiveType::Boolean => {
 
                write!(f, "boolean")?;
 
            }
 
            PrimitiveType::Byte => {
 
                write!(f, "byte")?;
 
            }
 
            PrimitiveType::Short => {
 
                write!(f, "short")?;
 
            }
 
            PrimitiveType::Int => {
 
                write!(f, "int")?;
 
            }
 
            PrimitiveType::Long => {
 
                write!(f, "long")?;
 
            }
 
        }
 
        if self.array {
 
            write!(f, "[]")
 
        } else {
 
            Ok(())
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Field {
 
    Length,
 
    Symbolic(FieldSymbolic),
 
}
 
impl Field {
 
    pub fn is_length(&self) -> bool {
 
        match self {
 
            Field::Length => true,
 
            _ => false,
 
        }
 
    }
 

	
 
    pub fn as_symbolic(&self) -> &FieldSymbolic {
 
        match self {
 
            Field::Symbolic(v) => v,
 
            _ => unreachable!("attempted to get Field::Symbolic from {:?}", self)
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct FieldSymbolic {
 
    // Phase 1: Parser
 
    pub(crate) identifier: Identifier,
 
    // Phase 3: Typing
 
    pub(crate) definition: Option<DefinitionId>,
 
    pub(crate) field_idx: usize,
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum Scope {
 
    Definition(DefinitionId),
 
    Regular(BlockStatementId),
 
    Synchronous((SynchronousStatementId, BlockStatementId)),
 
}
 

	
 
impl Scope {
 
    pub fn is_block(&self) -> bool {
 
        match &self {
 
            Scope::Definition(_) => false,
 
            Scope::Regular(_) => true,
 
            Scope::Synchronous(_) => true,
 
        }
 
    }
 
    pub fn to_block(&self) -> BlockStatementId {
 
        match &self {
 
            Scope::Regular(id) => *id,
 
            Scope::Synchronous((_, id)) => *id,
 
            _ => panic!("unable to get BlockStatement from Scope")
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Variable {
 
    Parameter(Parameter),
 
    Local(Local),
 
}
 

	
 
impl Variable {
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Variable::Parameter(var) => &var.identifier,
 
            Variable::Local(var) => &var.identifier,
 
        }
 
    }
 
    pub fn is_parameter(&self) -> bool {
 
        match self {
 
            Variable::Parameter(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_parameter(&self) -> &Parameter {
 
        match self {
 
            Variable::Parameter(result) => result,
 
            _ => panic!("Unable to cast `Variable` to `Parameter`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &Local {
 
        match self {
 
            Variable::Local(result) => result,
 
            _ => panic!("Unable to cast `Variable` to `Local`"),
 
        }
 
    }
 
    pub fn as_local_mut(&mut self) -> &mut Local {
 
        match self {
 
            Variable::Local(result) => result,
 
            _ => panic!("Unable to cast 'Variable' to 'Local'"),
 
        }
 
    }
 
}
 

	
 
/// TODO: Remove distinction between parameter/local and add an enum to indicate
 
///     the distinction between the two
 
#[derive(Debug, Clone)]
 
pub struct Parameter {
 
    pub this: ParameterId,
 
    // Phase 2: parser
 
    pub span: InputSpan,
 
    pub parser_type: ParserType,
 
    pub identifier: Identifier,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct Local {
 
    pub this: LocalId,
 
    // Phase 1: parser
 
    pub identifier: Identifier,
 
    pub parser_type: ParserType,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Definition {
 
    Struct(StructDefinition),
 
    Enum(EnumDefinition),
 
    Union(UnionDefinition),
 
    Component(ComponentDefinition),
 
    Function(FunctionDefinition),
 
}
 

	
 
impl Definition {
 
    pub fn is_struct(&self) -> bool {
 
        match self {
 
            Definition::Struct(_) => true,
 
            _ => false
 
        }
 
    }
 
    pub(crate) fn as_struct(&self) -> &StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut StructDefinition {
 
        match self {
 
            Definition::Struct(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'StructDefinition'"),
 
        }
 
    }
 
    pub fn is_enum(&self) -> bool {
 
        match self {
 
            Definition::Enum(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_enum(&self) -> &EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_enum_mut(&mut self) -> &mut EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub fn is_union(&self) -> bool {
 
        match self {
 
            Definition::Union(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_union(&self) -> &UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result, 
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub(crate) fn as_union_mut(&mut self) -> &mut UnionDefinition {
 
        match self {
 
            Definition::Union(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'UnionDefinition'"),
 
        }
 
    }
 
    pub fn is_component(&self) -> bool {
 
        match self {
 
            Definition::Component(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_component(&self) -> &ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub(crate) fn as_component_mut(&mut self) -> &mut ComponentDefinition {
 
        match self {
 
            Definition::Component(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Component`"),
 
        }
 
    }
 
    pub fn is_function(&self) -> bool {
 
        match self {
 
            Definition::Function(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub(crate) fn as_function(&self) -> &FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub(crate) fn as_function_mut(&mut self) -> &mut FunctionDefinition {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub fn defined_in(&self) -> RootId {
 
        match self {
 
            Definition::Struct(def) => def.defined_in,
 
            Definition::Enum(def) => def.defined_in,
 
            Definition::Union(def) => def.defined_in,
 
            Definition::Component(def) => def.defined_in,
 
            Definition::Function(def) => def.defined_in,
 
        }
 
    }
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Definition::Struct(def) => &def.identifier,
 
            Definition::Enum(def) => &def.identifier,
 
            Definition::Union(def) => &def.identifier,
 
            Definition::Component(def) => &def.identifier,
 
            Definition::Function(def) => &def.identifier,
 
        }
 
    }
 
    pub fn parameters(&self) -> &Vec<ParameterId> {
 
        // TODO: Fix this
 
        static EMPTY_VEC: Vec<ParameterId> = Vec::new();
 
        match self {
 
            Definition::Component(com) => &com.parameters,
 
            Definition::Function(fun) => &fun.parameters,
 
            _ => &EMPTY_VEC,
 
        }
 
    }
 
    pub fn body(&self) -> StatementId {
 
        // TODO: Fix this
 
    pub fn body(&self) -> BlockStatementId {
 
        match self {
 
            Definition::Component(com) => com.body,
 
            Definition::Function(fun) => fun.body,
 
            _ => panic!("cannot retrieve body (for EnumDefinition or StructDefinition)")
 
            _ => panic!("cannot retrieve body (for EnumDefinition/UnionDefinition or StructDefinition)")
 
        }
 
    }
 
    pub fn poly_vars(&self) -> &Vec<Identifier> {
 
        match self {
 
            Definition::Struct(def) => &def.poly_vars,
 
            Definition::Enum(def) => &def.poly_vars,
 
            Definition::Union(def) => &def.poly_vars,
 
            Definition::Component(def) => &def.poly_vars,
 
            Definition::Function(def) => &def.poly_vars,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructFieldDefinition {
 
    pub span: InputSpan,
 
    pub field: Identifier,
 
    pub parser_type: ParserType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct StructDefinition {
 
    pub this: StructDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub fields: Vec<StructFieldDefinition>
 
}
 

	
 
impl StructDefinition {
 
    pub(crate) fn new_empty(this: StructDefinitionId, span: InputSpan, identifier: Identifier, poly_vars: Vec<Identifier>) -> Self {
 
        Self{ this, span, identifier, poly_vars, fields: Vec::new() }
 
    pub(crate) fn new_empty(
 
        this: StructDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, fields: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum EnumVariantValue {
 
    None,
 
    Integer(i64),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumVariantDefinition {
 
    pub identifier: Identifier,
 
    pub value: EnumVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EnumDefinition {
 
    pub this: EnumDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub variants: Vec<EnumVariantDefinition>,
 
}
 

	
 
impl EnumDefinition {
 
    pub(crate) fn new_empty(this: EnumDefinitionId, span: InputSpan, identifier: Identifier, poly_vars: Vec<Identifier>) -> Self {
 
        Self{ this, span, identifier, poly_vars, variants: Vec::new() }
 
    pub(crate) fn new_empty(
 
        this: EnumDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum UnionVariantValue {
 
    None,
 
    Embedded(Vec<ParserType>),
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionVariantDefinition {
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub value: UnionVariantValue,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnionDefinition {
 
    pub this: UnionDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub variants: Vec<UnionVariantDefinition>,
 
}
 

	
 
impl UnionDefinition {
 
    pub(crate) fn new_empty(this: UnionDefinitionId, span: InputSpan, identifier: Identifier, poly_vars: Vec<Identifier>) -> Self {
 
        Self{ this, span, identifier, poly_vars, variants: Vec::new() }
 
    pub(crate) fn new_empty(
 
        this: UnionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ this, defined_in, span, identifier, poly_vars, variants: Vec::new() }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, Copy)]
 
pub enum ComponentVariant {
 
    Primitive,
 
    Composite,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ComponentDefinition {
 
    pub this: ComponentDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub span: InputSpan,
 
    pub variant: ComponentVariant,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub parameters: Vec<ParameterId>,
 
    pub body: StatementId,
 
    pub body: BlockStatementId,
 
}
 

	
 
impl ComponentDefinition {
 
    pub(crate) fn new_empty(this: ComponentDefinitionId, span: InputSpan, variant: ComponentVariant, identifier: Identifier, poly_vars: Vec<Identifier>) -> Self {
 
    pub(crate) fn new_empty(
 
        this: ComponentDefinitionId, defined_in: RootId, span: InputSpan,
 
        variant: ComponentVariant, identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self{ 
 
            this, span, variant, identifier, poly_vars,
 
            this, defined_in, span, variant, identifier, poly_vars,
 
            parameters: Vec::new(), 
 
            body: StatementId::new_invalid()
 
            body: BlockStatementId::new_invalid()
 
        }
 
    }
 
}
 

	
 
// Note that we will have function definitions for builtin functions as well. In
 
// that case the span, the identifier span and the body are all invalid.
 
#[derive(Debug, Clone)]
 
pub struct FunctionDefinition {
 
    pub this: FunctionDefinitionId,
 
    pub defined_in: RootId,
 
    // Phase 1: symbol scanning
 
    pub builtin: bool,
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Phase 2: parsing
 
    pub return_types: Vec<ParserType>,
 
    pub parameters: Vec<ParameterId>,
 
    pub body: StatementId,
 
    pub body: BlockStatementId,
 
}
 

	
 
impl FunctionDefinition {
 
    pub(crate) fn new_empty(this: FunctionDefinitionId, span: InputSpan, identifier: Identifier, poly_vars: Vec<Identifier>) -> Self {
 
    pub(crate) fn new_empty(
 
        this: FunctionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self {
 
            this,
 
            this, defined_in,
 
            builtin: false,
 
            span, identifier, poly_vars,
 
            return_types: Vec::new(),
 
            parameters: Vec::new(),
 
            body: StatementId::new_invalid(),
 
            body: BlockStatementId::new_invalid(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Statement {
 
    Block(BlockStatement),
 
    Local(LocalStatement),
 
    Labeled(LabeledStatement),
 
    If(IfStatement),
 
    EndIf(EndIfStatement),
 
    While(WhileStatement),
 
    EndWhile(EndWhileStatement),
 
    Break(BreakStatement),
 
    Continue(ContinueStatement),
 
    Synchronous(SynchronousStatement),
 
    EndSynchronous(EndSynchronousStatement),
 
    Return(ReturnStatement),
 
    Goto(GotoStatement),
 
    New(NewStatement),
 
    Expression(ExpressionStatement),
 
}
 

	
 
impl Statement {
 
    pub fn is_block(&self) -> bool {
 
        match self {
 
            Statement::Block(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_block(&self) -> &BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_block_mut(&mut self) -> &mut BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &LocalStatement {
 
        match self {
 
            Statement::Local(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LocalStatement`"),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        self.as_local().as_memory()
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        self.as_local().as_channel()
 
    }
 
    pub fn as_skip(&self) -> &SkipStatement {
 
        match self {
 
            Statement::Skip(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SkipStatement`"),
 
        }
 
    }
 
    pub fn as_labeled(&self) -> &LabeledStatement {
 
        match self {
 
            Statement::Labeled(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LabeledStatement`"),
 
        }
 
    }
 
    pub fn as_labeled_mut(&mut self) -> &mut LabeledStatement {
 
        match self {
 
            Statement::Labeled(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LabeledStatement`"),
 
        }
 
    }
 
    pub fn as_if(&self) -> &IfStatement {
 
        match self {
 
            Statement::If(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `IfStatement`"),
 
        }
 
    }
 
    pub fn as_if_mut(&mut self) -> &mut IfStatement {
 
        match self {
 
            Statement::If(result) => result,
 
            _ => panic!("Unable to cast 'Statement' to 'IfStatement'"),
 
        }
 
    }
 
    pub fn as_end_if(&self) -> &EndIfStatement {
 
        match self {
 
            Statement::EndIf(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndIfStatement`"),
 
        }
 
    }
 
    pub fn is_while(&self) -> bool {
 
        match self {
 
            Statement::While(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_while(&self) -> &WhileStatement {
 
        match self {
 
            Statement::While(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `WhileStatement`"),
 
        }
 
    }
 
    pub fn as_while_mut(&mut self) -> &mut WhileStatement {
 
        match self {
 
            Statement::While(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `WhileStatement`"),
 
        }
 
    }
 
    pub fn as_end_while(&self) -> &EndWhileStatement {
 
        match self {
 
            Statement::EndWhile(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndWhileStatement`"),
 
        }
 
    }
 
    pub fn as_break(&self) -> &BreakStatement {
 
        match self {
 
            Statement::Break(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BreakStatement`"),
 
        }
 
    }
 
    pub fn as_break_mut(&mut self) -> &mut BreakStatement {
 
        match self {
 
            Statement::Break(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BreakStatement`"),
 
        }
 
    }
 
    pub fn as_continue(&self) -> &ContinueStatement {
 
        match self {
 
            Statement::Continue(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ContinueStatement`"),
 
        }
 
    }
 
    pub fn as_continue_mut(&mut self) -> &mut ContinueStatement {
 
        match self {
 
            Statement::Continue(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ContinueStatement`"),
 
        }
 
    }
 
    pub fn as_synchronous(&self) -> &SynchronousStatement {
 
        match self {
 
            Statement::Synchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_synchronous_mut(&mut self) -> &mut SynchronousStatement {
 
        match self {
 
            Statement::Synchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `SynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_end_synchronous(&self) -> &EndSynchronousStatement {
 
        match self {
 
            Statement::EndSynchronous(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `EndSynchronousStatement`"),
 
        }
 
    }
 
    pub fn as_return(&self) -> &ReturnStatement {
 
        match self {
 
            Statement::Return(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ReturnStatement`"),
 
        }
 
    }
 
    pub fn as_goto(&self) -> &GotoStatement {
 
        match self {
 
            Statement::Goto(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `GotoStatement`"),
 
        }
 
    }
 
    pub fn as_goto_mut(&mut self) -> &mut GotoStatement {
 
        match self {
 
            Statement::Goto(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `GotoStatement`"),
 
        }
 
    }
 
    pub fn as_new(&self) -> &NewStatement {
 
        match self {
 
            Statement::New(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `NewStatement`"),
 
        }
 
    }
 
    pub fn as_expression(&self) -> &ExpressionStatement {
 
        match self {
 
            Statement::Expression(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ExpressionStatement`"),
 
        }
 
    }
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            Statement::Block(v) => v.span,
 
            Statement::Local(v) => v.span(),
 
            Statement::Labeled(v) => v.label.span,
 
            Statement::If(v) => v.span,
 
            Statement::While(v) => v.span,
 
            Statement::Break(v) => v.span,
 
            Statement::Continue(v) => v.span,
 
            Statement::Synchronous(v) => v.span,
 
            Statement::Return(v) => v.span,
 
            Statement::Goto(v) => v.span,
 
            Statement::New(v) => v.span,
 
            Statement::Expression(v) => v.span,
 
            Statement::EndIf(_) | Statement::EndWhile(_) | Statement::EndSynchronous(_) => unreachable!(),
 
        }
 
    }
 
    pub fn link_next(&mut self, next: StatementId) {
 
        match self {
 
            Statement::Block(_) => todo!(),
 
            Statement::Local(stmt) => match stmt {
 
                LocalStatement::Channel(stmt) => stmt.next = Some(next),
 
                LocalStatement::Memory(stmt) => stmt.next = Some(next),
 
            },
 
            Statement::EndIf(stmt) => stmt.next = Some(next),
 
            Statement::EndWhile(stmt) => stmt.next = Some(next),
 
            Statement::EndSynchronous(stmt) => stmt.next = Some(next),
 
            Statement::New(stmt) => stmt.next = Some(next),
 
            Statement::Expression(stmt) => stmt.next = Some(next),
 
            Statement::Return(_)
 
            | Statement::Break(_)
 
            | Statement::Continue(_)
 
            | Statement::Synchronous(_)
 
            | Statement::Goto(_)
 
            | Statement::While(_)
 
            | Statement::Labeled(_)
 
            | Statement::If(_) => unreachable!(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BlockStatement {
 
    pub this: BlockStatementId,
 
    // Phase 1: parser
 
    pub is_implicit: bool,
 
    pub span: InputSpan, // of the complete block
 
    pub statements: Vec<StatementId>,
 
    // Phase 2: linker
 
    pub parent_scope: Option<Scope>,
 
    pub relative_pos_in_parent: u32,
 
    pub locals: Vec<LocalId>,
 
    pub labels: Vec<LabeledStatementId>,
 
}
 

	
 
impl BlockStatement {
 
    pub fn parent_block(&self, h: &Heap) -> Option<BlockStatementId> {
 
        let parent = self.parent_scope.unwrap();
 
        match parent {
 
            Scope::Definition(_) => {
 
                // If the parent scope is a definition, then there is no
 
                // parent block.
 
                None
 
            }
 
            Scope::Synchronous((parent, _)) => {
 
                // It is always the case that when this function is called,
 
                // the parent of a synchronous statement is a block statement:
 
                // nested synchronous statements are flagged illegal,
 
                // and that happens before resolving variables that
 
                // creates the parent_scope references in the first place.
 
                Some(h[parent].parent_scope(h).unwrap().to_block())
 
            }
 
            Scope::Regular(parent) => {
 
                // A variable scope is either a definition, sync, or block.
 
                Some(parent)
 
            }
 
        }
 
    }
 
    pub fn first(&self) -> StatementId {
 
        // It is an invariant (guaranteed by the lexer) that block statements have at least one stmt
 
        *self.statements.first().unwrap()
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum LocalStatement {
 
    Memory(MemoryStatement),
 
    Channel(ChannelStatement),
 
}
 

	
 
impl LocalStatement {
 
    pub fn this(&self) -> LocalStatementId {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.this.upcast(),
 
            LocalStatement::Channel(stmt) => stmt.this.upcast(),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        match self {
 
            LocalStatement::Memory(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `MemoryStatement`"),
 
        }
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        match self {
 
            LocalStatement::Channel(result) => result,
 
            _ => panic!("Unable to cast `LocalStatement` to `ChannelStatement`"),
 
        }
 
    }
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            LocalStatement::Channel(v) => v.span,
 
            LocalStatement::Memory(v) => v.span,
 
        }
 
    }
 
    pub fn next(&self) -> Option<StatementId> {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.next,
 
            LocalStatement::Channel(stmt) => stmt.next,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MemoryStatement {
 
    pub this: MemoryStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub variable: LocalId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
/// ChannelStatement is the declaration of an input and output port associated
 
/// with the same channel. Note that the polarity of the ports are from the
 
/// point of view of the component. So an output port is something that a
 
/// component uses to send data over (i.e. it is the "input end" of the
 
/// channel), and vice versa.
 
#[derive(Debug, Clone)]
 
pub struct ChannelStatement {
 
    pub this: ChannelStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "channel" keyword
 
    pub from: LocalId, // output
 
    pub to: LocalId,   // input
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LabeledStatement {
 
    pub this: LabeledStatementId,
 
    // Phase 1: parser
 
    pub label: Identifier,
 
    pub body: StatementId,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub in_sync: Option<SynchronousStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IfStatement {
 
    pub this: IfStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "if" keyword
 
    pub test: ExpressionId,
 
    pub true_body: BlockStatementId,
 
    pub false_body: Option<BlockStatementId>,
 
    // Phase 2: linker
 
    pub end_if: Option<EndIfStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndIfStatement {
 
    pub this: EndIfStatementId,
 
    // Phase 2: linker
 
    pub start_if: IfStatementId,
 
    pub position: InputPosition, // of corresponding if statement
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct WhileStatement {
 
    pub this: WhileStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "while" keyword
 
    pub test: ExpressionId,
 
    pub body: BlockStatementId,
 
    // Phase 2: linker
 
    pub end_while: Option<EndWhileStatementId>,
 
    pub in_sync: Option<SynchronousStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndWhileStatement {
 
    pub this: EndWhileStatementId,
 
    // Phase 2: linker
 
    pub start_while: WhileStatementId,
 
    pub position: InputPosition, // of corresponding while
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BreakStatement {
 
    pub this: BreakStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "break" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<EndWhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ContinueStatement {
 
    pub this: ContinueStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "continue" keyword
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<WhileStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SynchronousStatement {
 
    pub this: SynchronousStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "sync" keyword
 
    pub body: BlockStatementId,
 
    // Phase 2: linker
 
    pub end_sync: Option<EndSynchronousStatementId>,
 
    pub parent_scope: Option<Scope>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndSynchronousStatement {
 
    pub this: EndSynchronousStatementId,
 
    // Phase 2: linker
 
    pub position: InputPosition, // of corresponding sync statement
 
    pub start_sync: SynchronousStatementId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ReturnStatement {
 
    pub this: ReturnStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "return" keyword
 
    pub expressions: Vec<ExpressionId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct GotoStatement {
 
    pub this: GotoStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "goto" keyword
 
    pub label: Identifier,
 
    // Phase 2: linker
 
    pub target: Option<LabeledStatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct NewStatement {
 
    pub this: NewStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the "new" keyword
 
    pub expression: CallExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ExpressionStatement {
 
    pub this: ExpressionStatementId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
 
pub enum ExpressionParent {
 
    None, // only set during initial parsing
 
    If(IfStatementId),
 
    While(WhileStatementId),
 
    Return(ReturnStatementId),
 
    Assert(AssertStatementId),
 
    New(NewStatementId),
 
    ExpressionStmt(ExpressionStatementId),
 
    Expression(ExpressionId, u32) // index within expression (e.g LHS or RHS of expression)
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Expression {
 
    Assignment(AssignmentExpression),
 
    Binding(BindingExpression),
 
    Conditional(ConditionalExpression),
 
    Binary(BinaryExpression),
 
    Unary(UnaryExpression),
 
    Indexing(IndexingExpression),
 
    Slicing(SlicingExpression),
 
    Select(SelectExpression),
 
    Array(ArrayExpression),
 
    Literal(LiteralExpression),
 
    Call(CallExpression),
 
    Variable(VariableExpression),
 
}
 

	
 
impl Expression {
 
    pub fn as_assignment(&self) -> &AssignmentExpression {
 
        match self {
 
            Expression::Assignment(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `AssignmentExpression`"),
 
        }
 
    }
 
    pub fn as_conditional(&self) -> &ConditionalExpression {
 
        match self {
 
            Expression::Conditional(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ConditionalExpression`"),
 
        }
 
    }
 
    pub fn as_binary(&self) -> &BinaryExpression {
 
        match self {
 
            Expression::Binary(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `BinaryExpression`"),
 
        }
 
    }
 
    pub fn as_unary(&self) -> &UnaryExpression {
 
        match self {
 
            Expression::Unary(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `UnaryExpression`"),
 
        }
 
    }
 
    pub fn as_indexing(&self) -> &IndexingExpression {
 
        match self {
 
            Expression::Indexing(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `IndexingExpression`"),
 
        }
 
    }
 
    pub fn as_slicing(&self) -> &SlicingExpression {
 
        match self {
 
            Expression::Slicing(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `SlicingExpression`"),
 
        }
 
    }
 
    pub fn as_select(&self) -> &SelectExpression {
 
        match self {
 
            Expression::Select(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `SelectExpression`"),
 
        }
 
    }
 
    pub fn as_array(&self) -> &ArrayExpression {
 
        match self {
 
            Expression::Array(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ArrayExpression`"),
 
        }
 
    }
 
    pub fn as_constant(&self) -> &LiteralExpression {
 
        match self {
 
            Expression::Literal(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `ConstantExpression`"),
 
        }
 
    }
 
    pub fn as_call(&self) -> &CallExpression {
 
        match self {
 
            Expression::Call(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `CallExpression`"),
 
        }
 
    }
 
    pub fn as_call_mut(&mut self) -> &mut CallExpression {
 
        match self {
 
            Expression::Call(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `CallExpression`"),
 
        }
 
    }
 
    pub fn as_variable(&self) -> &VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 
    pub fn as_variable_mut(&mut self) -> &mut VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent(&self) -> &ExpressionParent {
 
        match self {
 
            Expression::Assignment(expr) => &expr.parent,
 
            Expression::Binding(expr) => &expr.parent,
 
            Expression::Conditional(expr) => &expr.parent,
 
            Expression::Binary(expr) => &expr.parent,
 
            Expression::Unary(expr) => &expr.parent,
 
            Expression::Indexing(expr) => &expr.parent,
 
            Expression::Slicing(expr) => &expr.parent,
 
            Expression::Select(expr) => &expr.parent,
 
            Expression::Array(expr) => &expr.parent,
 
            Expression::Literal(expr) => &expr.parent,
 
            Expression::Call(expr) => &expr.parent,
 
            Expression::Variable(expr) => &expr.parent,
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent_expr_id(&self) -> Option<ExpressionId> {
 
        if let ExpressionParent::Expression(id, _) = self.parent() {
 
            Some(*id)
 
        } else {
 
            None
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn set_parent(&mut self, parent: ExpressionParent) {
 
        match self {
 
            Expression::Assignment(expr) => expr.parent = parent,
 
            Expression::Binding(expr) => expr.parent = parent,
 
            Expression::Conditional(expr) => expr.parent = parent,
 
            Expression::Binary(expr) => expr.parent = parent,
 
            Expression::Unary(expr) => expr.parent = parent,
 
            Expression::Indexing(expr) => expr.parent = parent,
 
            Expression::Slicing(expr) => expr.parent = parent,
 
            Expression::Select(expr) => expr.parent = parent,
 
            Expression::Array(expr) => expr.parent = parent,
 
            Expression::Literal(expr) => expr.parent = parent,
 
            Expression::Call(expr) => expr.parent = parent,
 
            Expression::Variable(expr) => expr.parent = parent,
 
        }
 
    }
 
    pub fn get_type(&self) -> &ConcreteType {
 
        match self {
 
            Expression::Assignment(expr) => &expr.concrete_type,
 
            Expression::Binding(expr) => &expr.concrete_type,
 
            Expression::Conditional(expr) => &expr.concrete_type,
 
            Expression::Binary(expr) => &expr.concrete_type,
 
            Expression::Unary(expr) => &expr.concrete_type,
 
            Expression::Indexing(expr) => &expr.concrete_type,
 
            Expression::Slicing(expr) => &expr.concrete_type,
 
            Expression::Select(expr) => &expr.concrete_type,
 
            Expression::Array(expr) => &expr.concrete_type,
 
            Expression::Literal(expr) => &expr.concrete_type,
 
            Expression::Call(expr) => &expr.concrete_type,
 
            Expression::Variable(expr) => &expr.concrete_type,
 
        }
 
    }
 

	
 
    // TODO: @cleanup
 
    pub fn get_type_mut(&mut self) -> &mut ConcreteType {
 
        match self {
 
            Expression::Assignment(expr) => &mut expr.concrete_type,
 
            Expression::Binding(expr) => &mut expr.concrete_type,
 
            Expression::Conditional(expr) => &mut expr.concrete_type,
 
            Expression::Binary(expr) => &mut expr.concrete_type,
 
            Expression::Unary(expr) => &mut expr.concrete_type,
 
            Expression::Indexing(expr) => &mut expr.concrete_type,
 
            Expression::Slicing(expr) => &mut expr.concrete_type,
 
            Expression::Select(expr) => &mut expr.concrete_type,
 
            Expression::Array(expr) => &mut expr.concrete_type,
 
            Expression::Literal(expr) => &mut expr.concrete_type,
 
            Expression::Call(expr) => &mut expr.concrete_type,
 
            Expression::Variable(expr) => &mut expr.concrete_type,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum AssignmentOperator {
 
    Set,
 
    Multiplied,
 
    Divided,
 
    Remained,
 
    Added,
 
    Subtracted,
 
    ShiftedLeft,
 
    ShiftedRight,
 
    BitwiseAnded,
 
    BitwiseXored,
 
    BitwiseOred,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct AssignmentExpression {
 
    pub this: AssignmentExpressionId,
 
    // Phase 2: parser
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: AssignmentOperator,
 
    pub right: ExpressionId,
 
    // Phase 3: linker
 
    pub parent: ExpressionParent,
 
    // Phase 4: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BindingExpression {
 
    pub this: BindingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub left: LiteralExpressionId,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ConditionalExpression {
 
    pub this: ConditionalExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of question mark operator
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum BinaryOperator {
 
    Concatenate,
 
    LogicalOr,
 
    LogicalAnd,
 
    BitwiseOr,
 
    BitwiseXor,
 
    BitwiseAnd,
 
    Equality,
 
    Inequality,
 
    LessThan,
 
    GreaterThan,
 
    LessThanEqual,
 
    GreaterThanEqual,
 
    ShiftLeft,
 
    ShiftRight,
 
    Add,
 
    Subtract,
 
    Multiply,
 
    Divide,
 
    Remainder,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the operator
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq)]
 
pub enum UnaryOperation {
 
    Positive,
 
    Negative,
 
    BitwiseNot,
 
    LogicalNot,
 
    PreIncrement,
 
    PreDecrement,
 
    PostIncrement,
 
    PostDecrement,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the operator
 
    pub operation: UnaryOperation,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // from '[' to ']';
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan, // of the '.'
 
    pub subject: ExpressionId,
 
    pub field: Field,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub parser_type: ParserType, // of the function call
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    pub definition: DefinitionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Method {
 
    // Builtin
 
    Get,
 
    Put,
 
    Fires,
 
    Create,
 
    Length,
 
    Assert,
 
    UserFunction,
 
    UserComponent,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct MethodSymbolic {
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) definition: DefinitionId
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralExpression {
 
    pub this: LiteralExpressionId,
 
    // Phase 1: parser
 
    pub span: InputSpan,
 
    pub value: Literal,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub enum Literal {
 
    Null, // message
 
    True,
 
    False,
 
    Character(char),
 
    String(StringRef<'static>),
 
    Integer(LiteralInteger),
 
    Struct(LiteralStruct),
 
    Enum(LiteralEnum),
 
    Union(LiteralUnion),
 
    Array(Vec<ExpressionId>),
 
}
 

	
 
impl Literal {
 
    pub(crate) fn as_struct(&self) -> &LiteralStruct {
 
        if let Literal::Struct(literal) = self{
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Struct", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_struct_mut(&mut self) -> &mut LiteralStruct {
 
        if let Literal::Struct(literal) = self{
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Struct", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum(&self) -> &LiteralEnum {
 
        if let Literal::Enum(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Enum", self)
 
        }
 
    }
 

	
 
    pub(crate) fn as_union(&self) -> &LiteralUnion {
 
        if let Literal::Union(literal) = self {
 
            literal
 
        } else {
 
            unreachable!("Attempted to obtain {:?} as Literal::Union", self)
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralInteger {
 
    pub(crate) unsigned_value: u64,
 
    pub(crate) negated: bool, // for constant expression evaluation, TODO
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStructField {
 
    // Phase 1: parser
 
    pub(crate) identifier: Identifier,
 
    pub(crate) value: ExpressionId,
 
    // Phase 2: linker
 
    pub(crate) field_idx: usize, // in struct definition
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralStruct {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) fields: Vec<LiteralStructField>,
 
    pub(crate) definition: DefinitionId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralEnum {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in the type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralUnion {
 
    // Phase 1: parser
 
    pub(crate) parser_type: ParserType,
 
    pub(crate) variant: Identifier,
 
    pub(crate) values: Vec<ExpressionId>,
 
    pub(crate) definition: DefinitionId,
 
    // Phase 2: linker
 
    pub(crate) variant_idx: usize, // as present in type table
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct VariableExpression {
 
    pub this: VariableExpressionId,
 
    // Phase 1: parser
 
    pub identifier: Identifier,
 
    // Phase 2: linker
 
    pub declaration: Option<VariableId>,
 
    pub parent: ExpressionParent,
 
    // Phase 3: type checking
 
    pub concrete_type: ConcreteType,
 
}
 
\ No newline at end of file
src/protocol/parser/depth_visitor.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 

	
 
// The following indirection is needed due to a bug in the cbindgen tool.
 
type Unit = ();
 
pub(crate) type VisitorError = (InputPosition, String); // TODO: Revise when multi-file compiling is in place
 
pub(crate) type VisitorResult = Result<Unit, VisitorError>;
 

	
 
pub(crate) trait Visitor: Sized {
 
    fn visit_protocol_description(&mut self, h: &mut Heap, pd: RootId) -> VisitorResult {
 
        recursive_protocol_description(self, h, pd)
 
    }
 
    fn visit_pragma(&mut self, _h: &mut Heap, _pragma: PragmaId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_import(&mut self, _h: &mut Heap, _import: ImportId) -> VisitorResult {
 
        Ok(())
 
    }
 

	
 
    fn visit_symbol_definition(&mut self, h: &mut Heap, def: DefinitionId) -> VisitorResult {
 
        recursive_symbol_definition(self, h, def)
 
    }
 
    fn visit_struct_definition(&mut self, _h: &mut Heap, _def: StructId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_enum_definition(&mut self, _h: &mut Heap, _def: EnumId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_union_definition(&mut self, _h: &mut Heap, _def: UnionId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_component_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_component_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        recursive_component_definition(self, h, def)
 
    }
 
    fn visit_composite_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_composite_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        recursive_composite_definition(self, h, def)
 
    }
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        recursive_primitive_definition(self, h, def)
 
    }
 
    fn visit_function_definition(&mut self, h: &mut Heap, def: FunctionId) -> VisitorResult {
 
        recursive_function_definition(self, h, def)
 
    }
 

	
 
    fn visit_variable_declaration(&mut self, h: &mut Heap, decl: VariableId) -> VisitorResult {
 
        recursive_variable_declaration(self, h, decl)
 
    }
 
    fn visit_parameter_declaration(&mut self, _h: &mut Heap, _decl: ParameterId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_local_declaration(&mut self, _h: &mut Heap, _decl: LocalId) -> VisitorResult {
 
        Ok(())
 
    }
 

	
 
    fn visit_statement(&mut self, h: &mut Heap, stmt: StatementId) -> VisitorResult {
 
        recursive_statement(self, h, stmt)
 
    }
 
    fn visit_local_statement(&mut self, h: &mut Heap, stmt: LocalStatementId) -> VisitorResult {
 
        recursive_local_statement(self, h, stmt)
 
    }
 
    fn visit_memory_statement(&mut self, _h: &mut Heap, _stmt: MemoryStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_channel_statement(
 
        &mut self,
 
        _h: &mut Heap,
 
        _stmt: ChannelStatementId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_block_statement(&mut self, h: &mut Heap, stmt: BlockStatementId) -> VisitorResult {
 
        recursive_block_statement(self, h, stmt)
 
    }
 
    fn visit_labeled_statement(&mut self, h: &mut Heap, stmt: LabeledStatementId) -> VisitorResult {
 
        recursive_labeled_statement(self, h, stmt)
 
    }
 
    fn visit_skip_statement(&mut self, _h: &mut Heap, _stmt: SkipStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_if_statement(&mut self, h: &mut Heap, stmt: IfStatementId) -> VisitorResult {
 
        recursive_if_statement(self, h, stmt)
 
    }
 
    fn visit_end_if_statement(&mut self, _h: &mut Heap, _stmt: EndIfStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_while_statement(&mut self, h: &mut Heap, stmt: WhileStatementId) -> VisitorResult {
 
        recursive_while_statement(self, h, stmt)
 
    }
 
    fn visit_end_while_statement(&mut self, _h: &mut Heap, _stmt: EndWhileStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_break_statement(&mut self, _h: &mut Heap, _stmt: BreakStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_continue_statement(
 
        &mut self,
 
        _h: &mut Heap,
 
        _stmt: ContinueStatementId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        recursive_synchronous_statement(self, h, stmt)
 
    }
 
    fn visit_end_synchronous_statement(&mut self, _h: &mut Heap, _stmt: EndSynchronousStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_return_statement(&mut self, h: &mut Heap, stmt: ReturnStatementId) -> VisitorResult {
 
        recursive_return_statement(self, h, stmt)
 
    }
 
    fn visit_assert_statement(&mut self, h: &mut Heap, stmt: AssertStatementId) -> VisitorResult {
 
        recursive_assert_statement(self, h, stmt)
 
    }
 
    fn visit_goto_statement(&mut self, _h: &mut Heap, _stmt: GotoStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_new_statement(&mut self, h: &mut Heap, stmt: NewStatementId) -> VisitorResult {
 
        recursive_new_statement(self, h, stmt)
 
    }
 
    fn visit_expression_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: ExpressionStatementId,
 
    ) -> VisitorResult {
 
        recursive_expression_statement(self, h, stmt)
 
    }
 

	
 
    fn visit_expression(&mut self, h: &mut Heap, expr: ExpressionId) -> VisitorResult {
 
        recursive_expression(self, h, expr)
 
    }
 
    fn visit_assignment_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: AssignmentExpressionId,
 
    ) -> VisitorResult {
 
        recursive_assignment_expression(self, h, expr)
 
    }
 
    fn visit_binding_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: BindingExpressionId
 
    ) -> VisitorResult {
 
        recursive_binding_expression(self, h, expr)
 
    }
 
    fn visit_conditional_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: ConditionalExpressionId,
 
    ) -> VisitorResult {
 
        recursive_conditional_expression(self, h, expr)
 
    }
 
    fn visit_binary_expression(&mut self, h: &mut Heap, expr: BinaryExpressionId) -> VisitorResult {
 
        recursive_binary_expression(self, h, expr)
 
    }
 
    fn visit_unary_expression(&mut self, h: &mut Heap, expr: UnaryExpressionId) -> VisitorResult {
 
        recursive_unary_expression(self, h, expr)
 
    }
 
    fn visit_indexing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: IndexingExpressionId,
 
    ) -> VisitorResult {
 
        recursive_indexing_expression(self, h, expr)
 
    }
 
    fn visit_slicing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: SlicingExpressionId,
 
    ) -> VisitorResult {
 
        recursive_slicing_expression(self, h, expr)
 
    }
 
    fn visit_select_expression(&mut self, h: &mut Heap, expr: SelectExpressionId) -> VisitorResult {
 
        recursive_select_expression(self, h, expr)
 
    }
 
    fn visit_array_expression(&mut self, h: &mut Heap, expr: ArrayExpressionId) -> VisitorResult {
 
        recursive_array_expression(self, h, expr)
 
    }
 
    fn visit_call_expression(&mut self, h: &mut Heap, expr: CallExpressionId) -> VisitorResult {
 
        recursive_call_expression(self, h, expr)
 
    }
 
    fn visit_constant_expression(
 
        &mut self,
 
        _h: &mut Heap,
 
        _expr: LiteralExpressionId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_variable_expression(
 
        &mut self,
 
        _h: &mut Heap,
 
        _expr: VariableExpressionId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
// Bubble-up helpers
 
fn recursive_parameter_as_variable<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    param: ParameterId,
 
) -> VisitorResult {
 
    this.visit_variable_declaration(h, param.upcast())
 
}
 

	
 
fn recursive_local_as_variable<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    local: LocalId,
 
) -> VisitorResult {
 
    this.visit_variable_declaration(h, local.upcast())
 
}
 

	
 
fn recursive_call_expression_as_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    call: CallExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, call.upcast())
 
}
 

	
 
// Recursive procedures
 
fn recursive_protocol_description<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    pd: RootId,
 
) -> VisitorResult {
 
    for &pragma in h[pd].pragmas.clone().iter() {
 
        this.visit_pragma(h, pragma)?;
 
    }
 
    for &import in h[pd].imports.clone().iter() {
 
        this.visit_import(h, import)?;
 
    }
 
    for &def in h[pd].definitions.clone().iter() {
 
        this.visit_symbol_definition(h, def)?;
 
    }
 
    Ok(())
 
}
 

	
 
fn recursive_symbol_definition<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    def: DefinitionId,
 
) -> VisitorResult {
 
    // We clone the definition in case it is modified
 
    // TODO: Fix me
 
    match h[def].clone() {
 
        Definition::Struct(def) => this.visit_struct_definition(h, def.this),
 
        Definition::Enum(def) => this.visit_enum_definition(h, def.this),
 
        Definition::Union(def) => this.visit_union_definition(h, def.this),
 
        Definition::Component(cdef) => this.visit_component_definition(h, cdef.this),
 
        Definition::Function(fdef) => this.visit_function_definition(h, fdef.this),
 
    }
 
}
 

	
 
fn recursive_component_definition<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    def: ComponentId,
 
    def: ComponentDefinitionId,
 
) -> VisitorResult {
 
    let component_variant = h[def].variant;
 
    match component_variant {
 
        ComponentVariant::Primitive => this.visit_primitive_definition(h, def),
 
        ComponentVariant::Composite => this.visit_composite_definition(h, def),
 
    }
 
}
 

	
 
fn recursive_composite_definition<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    def: ComponentId,
 
    def: ComponentDefinitionId,
 
) -> VisitorResult {
 
    for &param in h[def].parameters.clone().iter() {
 
        recursive_parameter_as_variable(this, h, param)?;
 
    }
 
    this.visit_statement(h, h[def].body)
 
    this.visit_block_statement(h, h[def].body)
 
}
 

	
 
fn recursive_primitive_definition<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    def: ComponentId,
 
    def: ComponentDefinitionId,
 
) -> VisitorResult {
 
    for &param in h[def].parameters.clone().iter() {
 
        recursive_parameter_as_variable(this, h, param)?;
 
    }
 
    this.visit_statement(h, h[def].body)
 
    this.visit_block_statement(h, h[def].body)
 
}
 

	
 
fn recursive_function_definition<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    def: FunctionId,
 
) -> VisitorResult {
 
    for &param in h[def].parameters.clone().iter() {
 
        recursive_parameter_as_variable(this, h, param)?;
 
    }
 
    this.visit_statement(h, h[def].body)
 
}
 

	
 
fn recursive_variable_declaration<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    decl: VariableId,
 
) -> VisitorResult {
 
    match h[decl].clone() {
 
        Variable::Parameter(decl) => this.visit_parameter_declaration(h, decl.this),
 
        Variable::Local(decl) => this.visit_local_declaration(h, decl.this),
 
    }
 
}
 

	
 
fn recursive_statement<T: Visitor>(this: &mut T, h: &mut Heap, stmt: StatementId) -> VisitorResult {
 
    match h[stmt].clone() {
 
        Statement::Block(stmt) => this.visit_block_statement(h, stmt.this),
 
        Statement::Local(stmt) => this.visit_local_statement(h, stmt.this()),
 
        Statement::Skip(stmt) => this.visit_skip_statement(h, stmt.this),
 
        Statement::Labeled(stmt) => this.visit_labeled_statement(h, stmt.this),
 
        Statement::If(stmt) => this.visit_if_statement(h, stmt.this),
 
        Statement::While(stmt) => this.visit_while_statement(h, stmt.this),
 
        Statement::Break(stmt) => this.visit_break_statement(h, stmt.this),
 
        Statement::Continue(stmt) => this.visit_continue_statement(h, stmt.this),
 
        Statement::Synchronous(stmt) => this.visit_synchronous_statement(h, stmt.this),
 
        Statement::Return(stmt) => this.visit_return_statement(h, stmt.this),
 
        Statement::Assert(stmt) => this.visit_assert_statement(h, stmt.this),
 
        Statement::Goto(stmt) => this.visit_goto_statement(h, stmt.this),
 
        Statement::New(stmt) => this.visit_new_statement(h, stmt.this),
 
        Statement::Expression(stmt) => this.visit_expression_statement(h, stmt.this),
 
        Statement::EndSynchronous(stmt) => this.visit_end_synchronous_statement(h, stmt.this),
 
        Statement::EndWhile(stmt) => this.visit_end_while_statement(h, stmt.this),
 
        Statement::EndIf(stmt) => this.visit_end_if_statement(h, stmt.this),
 
    }
 
}
 

	
 
fn recursive_block_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    block: BlockStatementId,
 
) -> VisitorResult {
 
    for &local in h[block].locals.clone().iter() {
 
        recursive_local_as_variable(this, h, local)?;
 
    }
 
    for &stmt in h[block].statements.clone().iter() {
 
        this.visit_statement(h, stmt)?;
 
    }
 
    Ok(())
 
}
 

	
 
fn recursive_local_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: LocalStatementId,
 
) -> VisitorResult {
 
    match h[stmt].clone() {
 
        LocalStatement::Channel(stmt) => this.visit_channel_statement(h, stmt.this),
 
        LocalStatement::Memory(stmt) => this.visit_memory_statement(h, stmt.this),
 
    }
 
}
 

	
 
fn recursive_labeled_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: LabeledStatementId,
 
) -> VisitorResult {
 
    this.visit_statement(h, h[stmt].body)
 
}
 

	
 
fn recursive_if_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: IfStatementId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[stmt].test)?;
 
    this.visit_statement(h, h[stmt].true_body)?;
 
    this.visit_statement(h, h[stmt].false_body)
 
    this.visit_block_statement(h, h[stmt].true_body)?;
 
    if let Some(false_body) = h[stmt].false_body {
 
        this.visit_block_statement(h, false_body)?;
 
    }
 
    Ok(())
 
}
 

	
 
fn recursive_while_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: WhileStatementId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[stmt].test)?;
 
    this.visit_statement(h, h[stmt].body)
 
    this.visit_block_statement(h, h[stmt].body)
 
}
 

	
 
fn recursive_synchronous_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: SynchronousStatementId,
 
) -> VisitorResult {
 
    // TODO: Check where this was used for
 
    // for &param in h[stmt].parameters.clone().iter() {
 
    //     recursive_parameter_as_variable(this, h, param)?;
 
    // }
 
    this.visit_statement(h, h[stmt].body)
 
    this.visit_block_statement(h, h[stmt].body)
 
}
 

	
 
fn recursive_return_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: ReturnStatementId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[stmt].expression)
 
}
 

	
 
fn recursive_assert_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: AssertStatementId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[stmt].expression)
 
}
 

	
 
fn recursive_new_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: NewStatementId,
 
) -> VisitorResult {
 
    recursive_call_expression_as_expression(this, h, h[stmt].expression)
 
}
 

	
 
fn recursive_expression_statement<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    stmt: ExpressionStatementId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[stmt].expression)
 
}
 

	
 
fn recursive_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: ExpressionId,
 
) -> VisitorResult {
 
    match h[expr].clone() {
 
        Expression::Assignment(expr) => this.visit_assignment_expression(h, expr.this),
 
        Expression::Binding(expr) => this.visit_binding_expression(h, expr.this),
 
        Expression::Conditional(expr) => this.visit_conditional_expression(h, expr.this),
 
        Expression::Binary(expr) => this.visit_binary_expression(h, expr.this),
 
        Expression::Unary(expr) => this.visit_unary_expression(h, expr.this),
 
        Expression::Indexing(expr) => this.visit_indexing_expression(h, expr.this),
 
        Expression::Slicing(expr) => this.visit_slicing_expression(h, expr.this),
 
        Expression::Select(expr) => this.visit_select_expression(h, expr.this),
 
        Expression::Array(expr) => this.visit_array_expression(h, expr.this),
 
        Expression::Literal(expr) => this.visit_constant_expression(h, expr.this),
 
        Expression::Call(expr) => this.visit_call_expression(h, expr.this),
 
        Expression::Variable(expr) => this.visit_variable_expression(h, expr.this),
 
    }
 
}
 

	
 
fn recursive_assignment_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: AssignmentExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].left)?;
 
    this.visit_expression(h, h[expr].right)
 
}
 

	
 
fn recursive_binding_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: BindingExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].left.upcast())?;
 
    this.visit_expression(h, h[expr].right)
 
}
 

	
 
fn recursive_conditional_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: ConditionalExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].test)?;
 
    this.visit_expression(h, h[expr].true_expression)?;
 
    this.visit_expression(h, h[expr].false_expression)
 
}
 

	
 
fn recursive_binary_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: BinaryExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].left)?;
 
    this.visit_expression(h, h[expr].right)
 
}
 

	
 
fn recursive_unary_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: UnaryExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].expression)
 
}
 

	
 
fn recursive_indexing_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: IndexingExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].subject)?;
 
    this.visit_expression(h, h[expr].index)
 
}
 

	
 
fn recursive_slicing_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: SlicingExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].subject)?;
 
    this.visit_expression(h, h[expr].from_index)?;
 
    this.visit_expression(h, h[expr].to_index)
 
}
 

	
 
fn recursive_select_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: SelectExpressionId,
 
) -> VisitorResult {
 
    this.visit_expression(h, h[expr].subject)
 
}
 

	
 
fn recursive_array_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: ArrayExpressionId,
 
) -> VisitorResult {
 
    for &expr in h[expr].elements.clone().iter() {
 
        this.visit_expression(h, expr)?;
 
    }
 
    Ok(())
 
}
 

	
 
fn recursive_call_expression<T: Visitor>(
 
    this: &mut T,
 
    h: &mut Heap,
 
    expr: CallExpressionId,
 
) -> VisitorResult {
 
    for &expr in h[expr].arguments.clone().iter() {
 
        this.visit_expression(h, expr)?;
 
    }
 
    Ok(())
 
}
 

	
 
// ====================
 
// Grammar Rules
 
// ====================
 

	
 
pub(crate) struct NestedSynchronousStatements {
 
    illegal: bool,
 
}
 

	
 
impl NestedSynchronousStatements {
 
    pub(crate) fn new() -> Self {
 
        NestedSynchronousStatements { illegal: false }
 
    }
 
}
 

	
 
impl Visitor for NestedSynchronousStatements {
 
    fn visit_composite_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_composite_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        assert!(!self.illegal);
 
        self.illegal = true;
 
        recursive_composite_definition(self, h, def)?;
 
        self.illegal = false;
 
        Ok(())
 
    }
 
    fn visit_function_definition(&mut self, h: &mut Heap, def: FunctionId) -> VisitorResult {
 
    fn visit_function_definition(&mut self, h: &mut Heap, def: FunctionDefinitionId) -> VisitorResult {
 
        assert!(!self.illegal);
 
        self.illegal = true;
 
        recursive_function_definition(self, h, def)?;
 
        self.illegal = false;
 
        Ok(())
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        if self.illegal {
 
            return Err((
 
                h[stmt].position(),
 
                "Illegal nested synchronous statement".to_string(),
 
            ));
 
        }
 
        self.illegal = true;
 
        recursive_synchronous_statement(self, h, stmt)?;
 
        self.illegal = false;
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct ChannelStatementOccurrences {
 
    illegal: bool,
 
}
 

	
 
impl ChannelStatementOccurrences {
 
    pub(crate) fn new() -> Self {
 
        ChannelStatementOccurrences { illegal: false }
 
    }
 
}
 

	
 
impl Visitor for ChannelStatementOccurrences {
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        assert!(!self.illegal);
 
        self.illegal = true;
 
        recursive_primitive_definition(self, h, def)?;
 
        self.illegal = false;
 
        Ok(())
 
    }
 
    fn visit_function_definition(&mut self, h: &mut Heap, def: FunctionId) -> VisitorResult {
 
        assert!(!self.illegal);
 
        self.illegal = true;
 
        recursive_function_definition(self, h, def)?;
 
        self.illegal = false;
 
        Ok(())
 
    }
 
    fn visit_channel_statement(&mut self, h: &mut Heap, stmt: ChannelStatementId) -> VisitorResult {
 
        if self.illegal {
 
            return Err((h[stmt].position(), "Illegal channel declaration".to_string()));
 
        }
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct FunctionStatementReturns {}
 

	
 
impl FunctionStatementReturns {
 
    pub(crate) fn new() -> Self {
 
        FunctionStatementReturns {}
 
    }
 
    fn function_error(&self, position: InputPosition) -> VisitorResult {
 
        Err((position, "Function definition must return".to_string()))
 
    }
 
}
 

	
 
impl Visitor for FunctionStatementReturns {
 
    fn visit_component_definition(&mut self, _h: &mut Heap, _def: ComponentId) -> VisitorResult {
 
    fn visit_component_definition(&mut self, _h: &mut Heap, _def: ComponentDefinitionId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_variable_declaration(&mut self, _h: &mut Heap, _decl: VariableId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_block_statement(&mut self, h: &mut Heap, block: BlockStatementId) -> VisitorResult {
 
        let len = h[block].statements.len();
 
        assert!(len > 0);
 
        self.visit_statement(h, h[block].statements[len - 1])
 
    }
 
    fn visit_skip_statement(&mut self, h: &mut Heap, stmt: SkipStatementId) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_break_statement(&mut self, h: &mut Heap, stmt: BreakStatementId) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_continue_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: ContinueStatementId,
 
    ) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_assert_statement(&mut self, h: &mut Heap, stmt: AssertStatementId) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_new_statement(&mut self, h: &mut Heap, stmt: NewStatementId) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_expression_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: ExpressionStatementId,
 
    ) -> VisitorResult {
 
        self.function_error(h[stmt].position)
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct ComponentStatementReturnNew {
 
    illegal_new: bool,
 
    illegal_return: bool,
 
}
 

	
 
impl ComponentStatementReturnNew {
 
    pub(crate) fn new() -> Self {
 
        ComponentStatementReturnNew { illegal_new: false, illegal_return: false }
 
    }
 
}
 

	
 
impl Visitor for ComponentStatementReturnNew {
 
    fn visit_component_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_component_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        assert!(!(self.illegal_new || self.illegal_return));
 
        self.illegal_return = true;
 
        recursive_component_definition(self, h, def)?;
 
        self.illegal_return = false;
 
        Ok(())
 
    }
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentId) -> VisitorResult {
 
    fn visit_primitive_definition(&mut self, h: &mut Heap, def: ComponentDefinitionId) -> VisitorResult {
 
        assert!(!self.illegal_new);
 
        self.illegal_new = true;
 
        recursive_primitive_definition(self, h, def)?;
 
        self.illegal_new = false;
 
        Ok(())
 
    }
 
    fn visit_function_definition(&mut self, h: &mut Heap, def: FunctionId) -> VisitorResult {
 
        assert!(!(self.illegal_new || self.illegal_return));
 
        self.illegal_new = true;
 
        recursive_function_definition(self, h, def)?;
 
        self.illegal_new = false;
 
        Ok(())
 
    }
 
    fn visit_variable_declaration(&mut self, _h: &mut Heap, _decl: VariableId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_return_statement(&mut self, h: &mut Heap, stmt: ReturnStatementId) -> VisitorResult {
 
        if self.illegal_return {
 
            Err((h[stmt].position, "Component definition must not return".to_string()))
 
        } else {
 
            recursive_return_statement(self, h, stmt)
 
        }
 
    }
 
    fn visit_new_statement(&mut self, h: &mut Heap, stmt: NewStatementId) -> VisitorResult {
 
        if self.illegal_new {
 
            Err((
 
                h[stmt].position,
 
                "Symbol definition contains illegal new statement".to_string(),
 
            ))
 
        } else {
 
            recursive_new_statement(self, h, stmt)
 
        }
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct CheckBuiltinOccurrences {
 
    legal: bool,
 
}
 

	
 
impl CheckBuiltinOccurrences {
 
    pub(crate) fn new() -> Self {
 
        CheckBuiltinOccurrences { legal: false }
 
    }
 
}
 

	
 
impl Visitor for CheckBuiltinOccurrences {
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        assert!(!self.legal);
 
        self.legal = true;
 
        recursive_synchronous_statement(self, h, stmt)?;
 
        self.legal = false;
 
        Ok(())
 
    }
 
    fn visit_call_expression(&mut self, h: &mut Heap, expr: CallExpressionId) -> VisitorResult {
 
        match h[expr].method {
 
            Method::Get | Method::Fires => {
 
                if !self.legal {
 
                    return Err((h[expr].position, "Illegal built-in occurrence".to_string()));
 
                }
 
            }
 
            _ => {}
 
        }
 
        recursive_call_expression(self, h, expr)
 
    }
 
}
 

	
 
pub(crate) struct BuildScope {
 
    scope: Option<Scope>,
 
}
 

	
 
impl BuildScope {
 
    pub(crate) fn new() -> Self {
 
        BuildScope { scope: None }
 
    }
 
}
 

	
 
impl Visitor for BuildScope {
 
    fn visit_symbol_definition(&mut self, h: &mut Heap, def: DefinitionId) -> VisitorResult {
 
        assert!(self.scope.is_none());
 
        self.scope = Some(Scope::Definition(def));
 
        recursive_symbol_definition(self, h, def)?;
 
        self.scope = None;
 
        Ok(())
 
    }
 
    fn visit_block_statement(&mut self, h: &mut Heap, stmt: BlockStatementId) -> VisitorResult {
 
        assert!(!self.scope.is_none());
 
        let old = self.scope;
 
        // First store the current scope
 
        h[stmt].parent_scope = self.scope;
 
        // Then move scope down to current block
 
        self.scope = Some(Scope::Regular(stmt));
 
        recursive_block_statement(self, h, stmt)?;
 
        // Move scope back up
 
        self.scope = old;
 
        Ok(())
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        assert!(!self.scope.is_none());
 
        let old = self.scope;
 
        // First store the current scope
 
        h[stmt].parent_scope = self.scope;
 
        // Then move scope down to current sync
 
        // TODO: Should be legal-ish, but very wrong
 
        self.scope = Some(Scope::Synchronous((stmt, BlockStatementId(stmt.upcast()))));
 
        recursive_synchronous_statement(self, h, stmt)?;
 
        // Move scope back up
 
        self.scope = old;
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct UniqueStatementId(StatementId);
 

	
 
pub(crate) struct LinkStatements {
 
    prev: Option<UniqueStatementId>,
 
}
 

	
 
impl LinkStatements {
 
    pub(crate) fn new() -> Self {
 
        LinkStatements { prev: None }
 
    }
 
}
 

	
 
impl Visitor for LinkStatements {
 
    fn visit_symbol_definition(&mut self, h: &mut Heap, def: DefinitionId) -> VisitorResult {
 
        assert!(self.prev.is_none());
 
        recursive_symbol_definition(self, h, def)?;
 
        // Clear out last statement
 
        self.prev = None;
 
        Ok(())
 
    }
 
    fn visit_statement(&mut self, h: &mut Heap, stmt: StatementId) -> VisitorResult {
 
        if let Some(UniqueStatementId(prev)) = self.prev.take() {
 
            h[prev].link_next(stmt);
 
        }
 
        recursive_statement(self, h, stmt)
 
    }
 
    fn visit_local_statement(&mut self, _h: &mut Heap, stmt: LocalStatementId) -> VisitorResult {
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_labeled_statement(&mut self, h: &mut Heap, stmt: LabeledStatementId) -> VisitorResult {
 
        recursive_labeled_statement(self, h, stmt)
 
    }
 
    fn visit_skip_statement(&mut self, _h: &mut Heap, stmt: SkipStatementId) -> VisitorResult {
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_if_statement(&mut self, h: &mut Heap, stmt: IfStatementId) -> VisitorResult {
 
        // Link the two branches to the corresponding EndIf pseudo-statement
 
        let end_if_id = h[stmt].end_if;
 
        assert!(end_if_id.is_some());
 
        let end_if_id = end_if_id.unwrap();
 

	
 
        assert!(self.prev.is_none());
 
        self.visit_statement(h, h[stmt].true_body)?;
 
        self.visit_block_statement(h, h[stmt].true_body)?;
 
        if let Some(UniqueStatementId(prev)) = self.prev.take() {
 
            h[prev].link_next(end_if_id.upcast());
 
        }
 

	
 
        assert!(self.prev.is_none());
 
        self.visit_statement(h, h[stmt].false_body)?;
 
        if let Some(false_body) = h[stmt].false_body {
 
            self.visit_block_statement(h, false_body)?;
 
        }
 
        if let Some(UniqueStatementId(prev)) = self.prev.take() {
 
            h[prev].link_next(end_if_id.upcast());
 
        }
 

	
 
        // Use the pseudo-statement as the statement where to update the next pointer
 
        // self.prev = Some(UniqueStatementId(end_if_id.upcast()));
 
        Ok(())
 
    }
 
    fn visit_end_if_statement(&mut self, _h: &mut Heap, stmt: EndIfStatementId) -> VisitorResult {
 
        assert!(self.prev.is_none());
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_while_statement(&mut self, h: &mut Heap, stmt: WhileStatementId) -> VisitorResult {
 
        // We allocate a pseudo-statement, to which the break statement finds its target
 
        // Update the while's next statement to point to the pseudo-statement
 
        let end_while_id = h[stmt].end_while;
 
        assert!(end_while_id.is_some());
 
        // let end_while_id = end_while_id.unwrap();
 

	
 
        assert!(self.prev.is_none());
 
        self.visit_statement(h, h[stmt].body)?;
 
        self.visit_block_statement(h, h[stmt].body)?;
 
        // The body's next statement loops back to the while statement itself
 
        // Note: continue statements also loop back to the while statement itself
 
        if let Some(UniqueStatementId(prev)) = self.prev.take() {
 
            h[prev].link_next(stmt.upcast());
 
        }
 
        // Use the while statement as the statement where the next pointer is updated
 
        // self.prev = Some(UniqueStatementId(end_while_id.upcast()));
 
        Ok(())
 
    }
 
    fn visit_end_while_statement(&mut self, _h: &mut Heap, stmt: EndWhileStatementId) -> VisitorResult {
 
        assert!(self.prev.is_none());
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_break_statement(&mut self, _h: &mut Heap, _stmt: BreakStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_continue_statement(
 
        &mut self,
 
        _h: &mut Heap,
 
        _stmt: ContinueStatementId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        // Allocate a pseudo-statement, that is added for helping the evaluator to issue a command
 
        // that marks the end of the synchronous block. Every evaluation has to pause at this
 
        // point, only to resume later when the thread is selected as unique thread to continue.
 
        let end_sync_id = h[stmt].end_sync;
 
        assert!(end_sync_id.is_some());
 
        let end_sync_id = end_sync_id.unwrap();
 

	
 
        assert!(self.prev.is_none());
 
        self.visit_statement(h, h[stmt].body)?;
 
        self.visit_block_statement(h, h[stmt].body)?;
 
        // The body's next statement points to the pseudo element
 
        if let Some(UniqueStatementId(prev)) = self.prev.take() {
 
            h[prev].link_next(end_sync_id.upcast());
 
        }
 
        // Use the pseudo-statement as the statement where the next pointer is updated
 
        // self.prev = Some(UniqueStatementId(end_sync_id.upcast()));
 
        Ok(())
 
    }
 
    fn visit_end_synchronous_statement(&mut self, _h: &mut Heap, stmt: EndSynchronousStatementId) -> VisitorResult {
 
        assert!(self.prev.is_none());
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_return_statement(&mut self, _h: &mut Heap, _stmt: ReturnStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_assert_statement(&mut self, _h: &mut Heap, stmt: AssertStatementId) -> VisitorResult {
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_goto_statement(&mut self, _h: &mut Heap, _stmt: GotoStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
    fn visit_new_statement(&mut self, _h: &mut Heap, stmt: NewStatementId) -> VisitorResult {
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_expression_statement(
 
        &mut self,
 
        _h: &mut Heap,
 
        stmt: ExpressionStatementId,
 
    ) -> VisitorResult {
 
        self.prev = Some(UniqueStatementId(stmt.upcast()));
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct BuildLabels {
 
    block: Option<BlockStatementId>,
 
    sync_enclosure: Option<SynchronousStatementId>,
 
}
 

	
 
impl BuildLabels {
 
    pub(crate) fn new() -> Self {
 
        BuildLabels { block: None, sync_enclosure: None }
 
    }
 
}
 

	
 
impl Visitor for BuildLabels {
 
    fn visit_block_statement(&mut self, h: &mut Heap, stmt: BlockStatementId) -> VisitorResult {
 
        assert_eq!(self.block, h[stmt].parent_block(h));
 
        let old = self.block;
 
        self.block = Some(stmt);
 
        recursive_block_statement(self, h, stmt)?;
 
        self.block = old;
 
        Ok(())
 
    }
 
    fn visit_labeled_statement(&mut self, h: &mut Heap, stmt: LabeledStatementId) -> VisitorResult {
 
        assert!(!self.block.is_none());
 
        // Store label in current block (on the fly)
 
        h[self.block.unwrap()].labels.push(stmt);
 
        // Update synchronous scope of label
 
        h[stmt].in_sync = self.sync_enclosure;
 
        recursive_labeled_statement(self, h, stmt)
 
    }
 
    fn visit_while_statement(&mut self, h: &mut Heap, stmt: WhileStatementId) -> VisitorResult {
 
        h[stmt].in_sync = self.sync_enclosure;
 
        recursive_while_statement(self, h, stmt)
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        assert!(self.sync_enclosure.is_none());
 
        self.sync_enclosure = Some(stmt);
 
        recursive_synchronous_statement(self, h, stmt)?;
 
        self.sync_enclosure = None;
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct ResolveLabels {
 
    block: Option<BlockStatementId>,
 
    while_enclosure: Option<WhileStatementId>,
 
    sync_enclosure: Option<SynchronousStatementId>,
 
}
 

	
 
impl ResolveLabels {
 
    pub(crate) fn new() -> Self {
 
        ResolveLabels { block: None, while_enclosure: None, sync_enclosure: None }
 
    }
 
    fn check_duplicate_impl(
 
        h: &Heap,
 
        block: Option<BlockStatementId>,
 
        stmt: LabeledStatementId,
 
    ) -> VisitorResult {
 
        if let Some(block) = block {
 
            // Checking the parent first is important. Otherwise, labels
 
            // overshadow previously defined labels: and this is illegal!
 
            ResolveLabels::check_duplicate_impl(h, h[block].parent_block(h), stmt)?;
 
            // For the current block, check for a duplicate.
 
            for &other_stmt in h[block].labels.iter() {
 
                if other_stmt == stmt {
 
                    continue;
 
                } else {
 
                    if h[other_stmt].label == h[stmt].label {
 
                        return Err((h[stmt].position, "Duplicate label".to_string()));
 
                    }
 
                }
 
            }
 
        }
 
        Ok(())
 
    }
 
    fn check_duplicate(&self, h: &Heap, stmt: LabeledStatementId) -> VisitorResult {
 
        ResolveLabels::check_duplicate_impl(h, self.block, stmt)
 
    }
 
    fn get_target(
 
        &self,
 
        h: &Heap,
 
        id: &Identifier,
 
    ) -> Result<LabeledStatementId, VisitorError> {
 
        if let Some(stmt) = ResolveLabels::find_target(h, self.block, id) {
 
            Ok(stmt)
 
        } else {
 
            Err((id.position, "Unresolved label".to_string()))
 
        }
 
    }
 
    fn find_target(
 
        h: &Heap,
 
        block: Option<BlockStatementId>,
 
        id: &Identifier,
 
    ) -> Option<LabeledStatementId> {
 
        if let Some(block) = block {
 
            // It does not matter in what order we find the labels.
 
            // If there are duplicates: that is checked elsewhere.
 
            for &stmt in h[block].labels.iter() {
 
                if h[stmt].label == *id {
 
                    return Some(stmt);
 
                }
 
            }
 
            if let Some(stmt) = ResolveLabels::find_target(h, h[block].parent_block(h), id) {
 
                return Some(stmt);
 
            }
 
        }
 
        None
 
    }
 
}
 

	
 
impl Visitor for ResolveLabels {
 
    fn visit_block_statement(&mut self, h: &mut Heap, stmt: BlockStatementId) -> VisitorResult {
 
        assert_eq!(self.block, h[stmt].parent_block(h));
 
        let old = self.block;
 
        self.block = Some(stmt);
 
        recursive_block_statement(self, h, stmt)?;
 
        self.block = old;
 
        Ok(())
 
    }
 
    fn visit_labeled_statement(&mut self, h: &mut Heap, stmt: LabeledStatementId) -> VisitorResult {
 
        assert!(!self.block.is_none());
 
        self.check_duplicate(h, stmt)?;
 
        recursive_labeled_statement(self, h, stmt)
 
    }
 
    fn visit_while_statement(&mut self, h: &mut Heap, stmt: WhileStatementId) -> VisitorResult {
 
        let old = self.while_enclosure;
 
        self.while_enclosure = Some(stmt);
 
        recursive_while_statement(self, h, stmt)?;
 
        self.while_enclosure = old;
 
        Ok(())
 
    }
 
    fn visit_break_statement(&mut self, h: &mut Heap, stmt: BreakStatementId) -> VisitorResult {
 
        let the_while;
 
        if let Some(label) = &h[stmt].label {
 
            let target = self.get_target(h, label)?;
 
            let target = &h[h[target].body];
 
            if !target.is_while() {
 
                return Err((
 
                    h[stmt].position,
 
                    "Illegal break: target not a while statement".to_string(),
 
                ));
 
            }
 
            the_while = target.as_while();
 
            // TODO: check if break is nested under while
 
        } else {
 
            if self.while_enclosure.is_none() {
 
                return Err((
 
                    h[stmt].position,
 
                    "Illegal break: no surrounding while statement".to_string(),
 
                ));
 
            }
 
            the_while = &h[self.while_enclosure.unwrap()];
 
            // break is always nested under while, by recursive vistor
 
        }
 
        if the_while.in_sync != self.sync_enclosure {
 
            return Err((
 
                h[stmt].position,
 
                "Illegal break: synchronous statement escape".to_string(),
 
            ));
 
        }
 
        h[stmt].target = the_while.end_while;
 
        Ok(())
 
    }
 
    fn visit_continue_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: ContinueStatementId,
 
    ) -> VisitorResult {
 
        let the_while;
 
        if let Some(label) = &h[stmt].label {
 
            let target = self.get_target(h, label)?;
 
            let target = &h[h[target].body];
 
            if !target.is_while() {
 
                return Err((
 
                    h[stmt].position,
 
                    "Illegal continue: target not a while statement".to_string(),
 
                ));
 
            }
 
            the_while = target.as_while();
 
            // TODO: check if continue is nested under while
 
        } else {
 
            if self.while_enclosure.is_none() {
 
                return Err((
 
                    h[stmt].position,
 
                    "Illegal continue: no surrounding while statement".to_string(),
 
                ));
 
            }
 
            the_while = &h[self.while_enclosure.unwrap()];
 
            // continue is always nested under while, by recursive vistor
 
        }
 
        if the_while.in_sync != self.sync_enclosure {
 
            return Err((
 
                h[stmt].position,
 
                "Illegal continue: synchronous statement escape".to_string(),
 
            ));
 
        }
 
        h[stmt].target = Some(the_while.this);
 
        Ok(())
 
    }
 
    fn visit_synchronous_statement(
 
        &mut self,
 
        h: &mut Heap,
 
        stmt: SynchronousStatementId,
 
    ) -> VisitorResult {
 
        assert!(self.sync_enclosure.is_none());
 
        self.sync_enclosure = Some(stmt);
 
        recursive_synchronous_statement(self, h, stmt)?;
 
        self.sync_enclosure = None;
 
        Ok(())
 
    }
 
    fn visit_goto_statement(&mut self, h: &mut Heap, stmt: GotoStatementId) -> VisitorResult {
 
        let target = self.get_target(h, &h[stmt].label)?;
 
        if h[target].in_sync != self.sync_enclosure {
 
            return Err((
 
                h[stmt].position,
 
                "Illegal goto: synchronous statement escape".to_string(),
 
            ));
 
        }
 
        h[stmt].target = Some(target);
 
        Ok(())
 
    }
 
    fn visit_expression(&mut self, _h: &mut Heap, _expr: ExpressionId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct AssignableExpressions {
 
    assignable: bool,
 
}
 

	
 
impl AssignableExpressions {
 
    pub(crate) fn new() -> Self {
 
        AssignableExpressions { assignable: false }
 
    }
 
    fn error(&self, position: InputPosition) -> VisitorResult {
 
        Err((position, "Unassignable expression".to_string()))
 
    }
 
}
 

	
 
impl Visitor for AssignableExpressions {
 
    fn visit_assignment_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: AssignmentExpressionId,
 
    ) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            self.assignable = true;
 
            self.visit_expression(h, h[expr].left)?;
 
            self.assignable = false;
 
            self.visit_expression(h, h[expr].right)
 
        }
 
    }
 
    fn visit_conditional_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: ConditionalExpressionId,
 
    ) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_conditional_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_binary_expression(&mut self, h: &mut Heap, expr: BinaryExpressionId) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_binary_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_unary_expression(&mut self, h: &mut Heap, expr: UnaryExpressionId) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            match h[expr].operation {
 
                UnaryOperation::PostDecrement
 
                | UnaryOperation::PreDecrement
 
                | UnaryOperation::PostIncrement
 
                | UnaryOperation::PreIncrement => {
 
                    self.assignable = true;
 
                    recursive_unary_expression(self, h, expr)?;
 
                    self.assignable = false;
 
                    Ok(())
 
                }
 
                _ => recursive_unary_expression(self, h, expr),
 
            }
 
        }
 
    }
 
    fn visit_indexing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: IndexingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.assignable;
 
        self.assignable = false;
 
        recursive_indexing_expression(self, h, expr)?;
 
        self.assignable = old;
 
        Ok(())
 
    }
 
    fn visit_slicing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: SlicingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.assignable;
 
        self.assignable = false;
 
        recursive_slicing_expression(self, h, expr)?;
 
        self.assignable = old;
 
        Ok(())
 
    }
 
    fn visit_select_expression(&mut self, h: &mut Heap, expr: SelectExpressionId) -> VisitorResult {
 
        if h[expr].field.is_length() && self.assignable {
 
            return self.error(h[expr].position);
 
        }
 
        let old = self.assignable;
 
        self.assignable = false;
 
        recursive_select_expression(self, h, expr)?;
 
        self.assignable = old;
 
        Ok(())
 
    }
 
    fn visit_array_expression(&mut self, h: &mut Heap, expr: ArrayExpressionId) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_array_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_call_expression(&mut self, h: &mut Heap, expr: CallExpressionId) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_call_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_constant_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: LiteralExpressionId,
 
    ) -> VisitorResult {
 
        if self.assignable {
 
            self.error(h[expr].position)
 
        } else {
 
            Ok(())
 
        }
 
    }
 
    fn visit_variable_expression(
 
        &mut self,
 
        _h: &mut Heap,
 
        _expr: VariableExpressionId,
 
    ) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
pub(crate) struct IndexableExpressions {
 
    indexable: bool,
 
}
 

	
 
impl IndexableExpressions {
 
    pub(crate) fn new() -> Self {
 
        IndexableExpressions { indexable: false }
 
    }
 
    fn error(&self, position: InputPosition) -> VisitorResult {
 
        Err((position, "Unindexable expression".to_string()))
 
    }
 
}
 

	
 
impl Visitor for IndexableExpressions {
 
    fn visit_assignment_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: AssignmentExpressionId,
 
    ) -> VisitorResult {
 
        if self.indexable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_assignment_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_conditional_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: ConditionalExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = false;
 
        self.visit_expression(h, h[expr].test)?;
 
        self.indexable = old;
 
        self.visit_expression(h, h[expr].true_expression)?;
 
        self.visit_expression(h, h[expr].false_expression)
 
    }
 
    fn visit_binary_expression(&mut self, h: &mut Heap, expr: BinaryExpressionId) -> VisitorResult {
 
        if self.indexable && h[expr].operation != BinaryOperator::Concatenate {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_binary_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_unary_expression(&mut self, h: &mut Heap, expr: UnaryExpressionId) -> VisitorResult {
 
        if self.indexable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_unary_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_indexing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: IndexingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = true;
 
        self.visit_expression(h, h[expr].subject)?;
 
        self.indexable = false;
 
        self.visit_expression(h, h[expr].index)?;
 
        self.indexable = old;
 
        Ok(())
 
    }
 
    fn visit_slicing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: SlicingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = true;
 
        self.visit_expression(h, h[expr].subject)?;
 
        self.indexable = false;
 
        self.visit_expression(h, h[expr].from_index)?;
 
        self.visit_expression(h, h[expr].to_index)?;
 
        self.indexable = old;
 
        Ok(())
 
    }
 
    fn visit_select_expression(&mut self, h: &mut Heap, expr: SelectExpressionId) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = false;
 
        recursive_select_expression(self, h, expr)?;
 
        self.indexable = old;
 
        Ok(())
 
    }
 
    fn visit_array_expression(&mut self, h: &mut Heap, expr: ArrayExpressionId) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = false;
 
        recursive_array_expression(self, h, expr)?;
 
        self.indexable = old;
 
        Ok(())
 
    }
 
    fn visit_call_expression(&mut self, h: &mut Heap, expr: CallExpressionId) -> VisitorResult {
 
        let old = self.indexable;
 
        self.indexable = false;
 
        recursive_call_expression(self, h, expr)?;
 
        self.indexable = old;
 
        Ok(())
 
    }
 
    fn visit_constant_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: LiteralExpressionId,
 
    ) -> VisitorResult {
 
        if self.indexable {
 
            self.error(h[expr].position)
 
        } else {
 
            Ok(())
 
        }
 
    }
 
}
 

	
 
pub(crate) struct SelectableExpressions {
 
    selectable: bool,
 
}
 

	
 
impl SelectableExpressions {
 
    pub(crate) fn new() -> Self {
 
        SelectableExpressions { selectable: false }
 
    }
 
    fn error(&self, position: InputPosition) -> VisitorResult {
 
        Err((position, "Unselectable expression".to_string()))
 
    }
 
}
 

	
 
impl Visitor for SelectableExpressions {
 
    fn visit_assignment_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: AssignmentExpressionId,
 
    ) -> VisitorResult {
 
        // left-hand side of assignment can be skipped
 
        let old = self.selectable;
 
        self.selectable = false;
 
        self.visit_expression(h, h[expr].right)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_conditional_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: ConditionalExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        self.visit_expression(h, h[expr].test)?;
 
        self.selectable = old;
 
        self.visit_expression(h, h[expr].true_expression)?;
 
        self.visit_expression(h, h[expr].false_expression)
 
    }
 
    fn visit_binary_expression(&mut self, h: &mut Heap, expr: BinaryExpressionId) -> VisitorResult {
 
        if self.selectable && h[expr].operation != BinaryOperator::Concatenate {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_binary_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_unary_expression(&mut self, h: &mut Heap, expr: UnaryExpressionId) -> VisitorResult {
 
        if self.selectable {
 
            self.error(h[expr].position)
 
        } else {
 
            recursive_unary_expression(self, h, expr)
 
        }
 
    }
 
    fn visit_indexing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: IndexingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        recursive_indexing_expression(self, h, expr)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_slicing_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: SlicingExpressionId,
 
    ) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        recursive_slicing_expression(self, h, expr)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_select_expression(&mut self, h: &mut Heap, expr: SelectExpressionId) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        recursive_select_expression(self, h, expr)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_array_expression(&mut self, h: &mut Heap, expr: ArrayExpressionId) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        recursive_array_expression(self, h, expr)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_call_expression(&mut self, h: &mut Heap, expr: CallExpressionId) -> VisitorResult {
 
        let old = self.selectable;
 
        self.selectable = false;
 
        recursive_call_expression(self, h, expr)?;
 
        self.selectable = old;
 
        Ok(())
 
    }
 
    fn visit_constant_expression(
 
        &mut self,
 
        h: &mut Heap,
 
        expr: LiteralExpressionId,
 
    ) -> VisitorResult {
 
        if self.selectable {
 
            self.error(h[expr].position)
 
        } else {
 
            Ok(())
 
        }
 
    }
 
}
src/protocol/parser/mod.rs
Show inline comments
 
mod depth_visitor;
 
pub(crate) mod symbol_table;
 
pub(crate) mod symbol_table2;
 
pub(crate) mod type_table;
 
pub(crate) mod tokens;
 
pub(crate) mod token_parsing;
 
pub(crate) mod pass_tokenizer;
 
pub(crate) mod pass_symbols;
 
pub(crate) mod pass_imports;
 
pub(crate) mod pass_definitions;
 
mod type_resolver;
 
mod visitor;
 
mod visitor_linker;
 
mod utils;
 

	
 
use depth_visitor::*;
 
use tokens::*;
 
use crate::collections::*;
 
use symbol_table2::SymbolTable;
 
use visitor::Visitor2;
 
use visitor_linker::ValidityAndLinkerVisitor;
 
use type_resolver::{TypeResolvingVisitor, ResolveQueue};
 
use type_table::{TypeTable, TypeCtx};
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource};
 
use crate::protocol::lexer::*;
 

	
 
use std::collections::HashMap;
 
use crate::protocol::ast_printer::ASTWriter;
 

	
 
pub(crate) const LIMIT_NUM_TYPE_NODES: usize = 64;
 
pub(crate) const LIMIT_NUM_POLY_VARS: usize = 64;
 
pub(crate) const LIMIT_NUM_PROC_ARGS: usize = 64;
 

	
 
#[derive(PartialEq, Eq)]
 
pub enum ModuleCompilationPhase {
 
    Source,                 // only source is set
 
    Tokenized,              // source is tokenized
 
    SymbolsScanned,         // all definitions are linked to their type class
 
    ImportsResolved,        // all imports are added to the symbol table
 
    DefinitionsParsed,      // produced the AST for the entire module
 
    TypesParsed,            // added all definitions to the type table
 
    ValidatedAndLinked,     // AST is traversed and has linked the required AST nodes
 
    Typed,                  // Type inference and checking has been performed
 
}
 

	
 
pub struct Module {
 
    // Buffers
 
    source: InputSource,
 
    tokens: TokenBuffer,
 
    // Identifiers
 
    root_id: RootId,
 
    name: Option<(PragmaId, StringRef<'static>)>,
 
    version: Option<(PragmaId, i64)>,
 
    phase: ModuleCompilationPhase,
 
}
 

	
 
pub struct PassCtx<'a> {
 
    heap: &'a mut Heap,
 
    symbols: &'a mut SymbolTable,
 
    pool: &'a mut StringPool,
 
}
 

	
 
// TODO: @fixme, pub qualifier
 
pub(crate) struct LexedModule {
 
    pub(crate) source: InputSource,
 
    module_name: Vec<u8>,
 
    version: Option<u64>,
 
    pub(crate) root_id: RootId,
 
}
 

	
 
pub struct Parser {
 
    pub(crate) heap: Heap,
 
    pub(crate) modules: Vec<LexedModule>,
 
    pub(crate) module_lookup: HashMap<Vec<u8>, usize>, // from (optional) module name to `modules` idx
 
    pub(crate) symbol_table: SymbolTable,
 
    pub(crate) type_table: TypeTable,
 
}
 

	
 
impl Parser {
 
    pub fn new() -> Self {
 
        Parser{
 
            heap: Heap::new(),
 
            modules: Vec::new(),
 
            module_lookup: HashMap::new(),
 
            symbol_table: SymbolTable::new(),
 
            type_table: TypeTable::new(),
 
        }
 
    }
 

	
 
    pub fn feed(&mut self, mut source: InputSource) -> Result<RootId, ParseError> {
 
        // Lex the input source
 
        let mut lex = Lexer::new(&mut source);
 
        let pd = lex.consume_protocol_description(&mut self.heap)?;
 

	
 
        // Seek the module name and version
 
        let root = &self.heap[pd];
 
        let mut module_name_pos = InputPosition::default();
 
        let mut module_name = Vec::new();
 
        let mut module_version_pos = InputPosition::default();
 
        let mut module_version = None;
 

	
 
        for pragma in &root.pragmas {
 
            match &self.heap[*pragma] {
 
                Pragma::Module(module) => {
 
                    if !module_name.is_empty() {
 
                        return Err(
 
                            ParseError::new_error(&source, module.position, "Double definition of module name in the same file")
 
                                .with_postfixed_info(&source, module_name_pos, "Previous definition was here")
 
                        )
 
                    }
 

	
 
                    module_name_pos = module.position.clone();
 
                    module_name = module.value.clone();
 
                },
 
                Pragma::Version(version) => {
 
                    if module_version.is_some() {
 
                        return Err(
 
                            ParseError::new_error(&source, version.position, "Double definition of module version")
 
                                .with_postfixed_info(&source, module_version_pos, "Previous definition was here")
 
                        )
 
                    }
 

	
 
                    module_version_pos = version.position.clone();
 
                    module_version = Some(version.version);
 
                },
 
            }
 
        }
 

	
 
        // Add module to list of modules and prevent naming conflicts
 
        let cur_module_idx = self.modules.len();
 
        if let Some(prev_module_idx) = self.module_lookup.get(&module_name) {
 
            // Find `#module` statement in other module again
 
            let prev_module = &self.modules[*prev_module_idx];
 
            let prev_module_pos = self.heap[prev_module.root_id].pragmas
 
                .iter()
 
                .find_map(|p| {
 
                    match &self.heap[*p] {
 
                        Pragma::Module(module) => Some(module.position.clone()),
 
                        _ => None
 
                    }
 
                })
 
                .unwrap_or(InputPosition::default());
 

	
 
            let module_name_msg = if module_name.is_empty() {
 
                format!("a nameless module")
 
            } else {
 
                format!("module '{}'", String::from_utf8_lossy(&module_name))
 
            };
 

	
 
            return Err(
 
                ParseError::new_error(&source, module_name_pos, &format!("Double definition of {} across files", module_name_msg))
 
                    .with_postfixed_info(&prev_module.source, prev_module_pos, "Other definition was here")
 
            );
 
        }
 

	
 
        self.modules.push(LexedModule{
 
            source,
 
            module_name: module_name.clone(),
 
            version: module_version,
 
            root_id: pd
 
        });
 
        self.module_lookup.insert(module_name, cur_module_idx);
 
        Ok(pd)
 
    }
 

	
 
    fn resolve_symbols_and_types(&mut self) -> Result<(), ParseError> {
 
        // Construct the symbol table to resolve any imports and/or definitions,
 
        // then use the symbol table to actually annotate all of the imports.
 
        // If the type table is constructed correctly then all imports MUST be
 
        // resolvable.
 
        self.symbol_table.build(&self.heap, &self.modules)?;
 

	
 
        // Not pretty, but we need to work around rust's borrowing rules, it is
 
        // totally safe to mutate the contents of an AST element that we are
 
        // not borrowing anywhere else.
 
        let mut module_index = 0;
 
        let mut import_index = 0;
 
        loop {
 
            if module_index >= self.modules.len() {
 
                break;
 
            }
 

	
 
            let module_root_id = self.modules[module_index].root_id;
 
            let import_id = {
 
                let root = &self.heap[module_root_id];
 
                if import_index >= root.imports.len() {
 
                    module_index += 1;
 
                    import_index = 0;
 
                    continue
 
                }
 
                root.imports[import_index]
 
            };
 

	
 
            let import = &mut self.heap[import_id];
 
            match import {
 
                Import::Module(import) => {
 
                    debug_assert!(import.module_id.is_none(), "module import already resolved");
 
                    let target_module_id = self.symbol_table.resolve_module(&import.module)
 
                        .expect("module import is resolved by symbol table");
 
                    import.module_id = Some(target_module_id)
 
                },
 
                Import::Symbols(import) => {
 
                    debug_assert!(import.module_id.is_none(), "module of symbol import already resolved");
 
                    let target_module_id = self.symbol_table.resolve_module(&import.module)
 
                        .expect("symbol import's module is resolved by symbol table");
 
                    import.module_id = Some(target_module_id);
 

	
 
                    for symbol in &mut import.symbols {
 
                        debug_assert!(symbol.definition_id.is_none(), "symbol import already resolved");
 
                        let (_, target_definition_id) = self.symbol_table.resolve_identifier(module_root_id, &symbol.alias)
 
                            .expect("symbol import is resolved by symbol table")
 
                            .as_definition()
 
                            .expect("symbol import does not resolve to namespace symbol");
 
                        symbol.definition_id = Some(target_definition_id);
 
                    }
 
                }
 
            }
 

	
 
            import_index += 1;
 
        }
 

	
 
        // All imports in the AST are now annotated. We now use the symbol table
 
        // to construct the type table.
 
        let mut type_ctx = TypeCtx::new(&self.symbol_table, &mut self.heap, &self.modules);
 
        self.type_table.build_base_types(&mut type_ctx)?;
 

	
 
        Ok(())
 
    }
 

	
 
    pub fn parse(&mut self) -> Result<(), ParseError> {
 
        self.resolve_symbols_and_types()?;
 

	
 
        // Validate and link all modules
 
        let mut visit = ValidityAndLinkerVisitor::new();
 
        for module in &self.modules {
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module,
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            visit.visit_module(&mut ctx)?;
 
        }
 

	
 
        // Perform typechecking on all modules
 
        let mut visit = TypeResolvingVisitor::new();
 
        let mut queue = ResolveQueue::new();
 
        for module in &self.modules {
 
            let ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module,
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            TypeResolvingVisitor::queue_module_definitions(&ctx, &mut queue);   
 
        };
 
        while !queue.is_empty() {
 
            let top = queue.pop().unwrap();
 
            let mut ctx = visitor::Ctx{
 
                heap: &mut self.heap,
 
                module: &self.modules[top.root_id.index as usize],
 
                symbols: &mut self.symbol_table,
 
                types: &mut self.type_table,
 
            };
 
            visit.handle_module_definition(&mut ctx, &mut queue, top)?;
 
        }
 

	
 
        // Perform remaining steps
 
        // TODO: Phase out at some point
 
        for module in &self.modules {
 
            let root_id = module.root_id;
 
            if let Err((position, message)) = Self::parse_inner(&mut self.heap, root_id) {
 
                return Err(ParseError::new_error(&self.modules[0].source, position, &message))
 
            }
 
        }
 

	
 
        // let mut writer = ASTWriter::new();
 
        // let mut file = std::fs::File::create(std::path::Path::new("ast.txt")).unwrap();
 
        // writer.write_ast(&mut file, &self.heap);
 

	
 
        Ok(())
 
    }
 

	
 
    pub fn parse_inner(h: &mut Heap, pd: RootId) -> VisitorResult {
 
        // TODO: @cleanup, slowly phasing out old compiler
 
        // NestedSynchronousStatements::new().visit_protocol_description(h, pd)?;
 
        // ChannelStatementOccurrences::new().visit_protocol_description(h, pd)?;
 
        // FunctionStatementReturns::new().visit_protocol_description(h, pd)?;
 
        // ComponentStatementReturnNew::new().visit_protocol_description(h, pd)?;
 
        // CheckBuiltinOccurrences::new().visit_protocol_description(h, pd)?;
 
        // BuildSymbolDeclarations::new().visit_protocol_description(h, pd)?;
 
        // LinkCallExpressions::new().visit_protocol_description(h, pd)?;
 
        // BuildScope::new().visit_protocol_description(h, pd)?;
 
        // ResolveVariables::new().visit_protocol_description(h, pd)?;
 
        LinkStatements::new().visit_protocol_description(h, pd)?;
 
        // BuildLabels::new().visit_protocol_description(h, pd)?;
 
        // ResolveLabels::new().visit_protocol_description(h, pd)?;
 
        AssignableExpressions::new().visit_protocol_description(h, pd)?;
 
        IndexableExpressions::new().visit_protocol_description(h, pd)?;
 
        SelectableExpressions::new().visit_protocol_description(h, pd)?;
 

	
 
        Ok(())
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/pass_definitions.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::symbol_table2::*;
 
use super::{Module, ModuleCompilationPhase, PassCtx};
 
use super::tokens::*;
 
use super::token_parsing::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource, InputPosition2 as InputPosition, InputSpan, ParseError};
 
use crate::collections::*;
 

	
 
/// Parses all the tokenized definitions into actual AST nodes.
 
pub(crate) struct PassDefinitions {
 
    // State
 
    cur_definition: DefinitionId,
 
    // Temporary buffers of various kinds
 
    buffer: String,
 
    identifiers: Vec<Identifier>,
 
    struct_fields: Vec<StructFieldDefinition>,
 
    enum_variants: Vec<EnumVariantDefinition>,
 
    union_variants: Vec<UnionVariantDefinition>,
 
    parameters: Vec<ParameterId>,
 
    parameters: ScopedBuffer<ParameterId>,
 
    expressions: ScopedBuffer<ExpressionId>,
 
    statements: ScopedBuffer<StatementId>,
 
    parser_types: Vec<ParserType>,
 
}
 

	
 
impl PassDefinitions {
 
    pub(crate) fn parse(&mut self, modules: &mut [Module], module_idx: usize, ctx: &mut PassCtx) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let module_range = &module.tokens.ranges[0];
 
        debug_assert_eq!(module.phase, ModuleCompilationPhase::ImportsResolved);
 
        debug_assert_eq!(module_range.range_kind, TokenRangeKind::Module);
 

	
 
        // TODO: Very important to go through ALL ranges of the module so that we parse the entire
 
        //  input source. Only skip the ones we're certain we've handled before.
 
        // Although we only need to parse the definitions, we want to go through
 
        // code ranges as well such that we can throw errors if we get
 
        // unexpected tokens at the module level of the source.
 
        let mut range_idx = module_range.first_child_idx;
 
        loop {
 
            let range_idx_usize = range_idx as usize;
 
            let cur_range = &module.tokens.ranges[range_idx_usize];
 

	
 
            if cur_range.range_kind == TokenRangeKind::Definition {
 
                self.visit_definition_range(modules, module_idx, ctx, range_idx_usize)?;
 
            match cur_range.range_kind {
 
                TokenRangeKind::Module => unreachable!(), // should not be reachable
 
                TokenRangeKind::Pragma | TokenRangeKind::Import => continue, // already fully parsed
 
                TokenRangeKind::Definition | TokenRangeKind::Code => {}
 
            }
 

	
 
            self.visit_range(modules, module_idx, ctx, range_idx_usize)?;
 

	
 
            match cur_range.next_sibling_idx {
 
                Some(idx) => { range_idx = idx; },
 
                None => { break; },
 
            }
 
        }
 

	
 

	
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_definition_range(
 
    fn visit_range(
 
        &mut self, modules: &[Module], module_idx: usize, ctx: &mut PassCtx, range_idx: usize
 
    ) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let cur_range = &module.tokens.ranges[range_idx];
 
        debug_assert_eq!(cur_range.range_kind, TokenRangeKind::Definition);
 
        debug_assert!(cur_range.range_kind == TokenRangeKind::Definition || cur_range.range_kind == TokenRangeKind::Code);
 

	
 
        // Detect which definition we're parsing
 
        let mut iter = module.tokens.iter_range(cur_range);
 
        let keyword = peek_ident(&module.source, &mut iter).unwrap();
 
        match keyword {
 
            KW_STRUCT => {
 

	
 
            },
 
            KW_ENUM => {
 

	
 
            },
 
            KW_UNION => {
 

	
 
            },
 
            KW_FUNCTION => {
 

	
 
            },
 
            KW_PRIMITIVE => {
 

	
 
            },
 
            KW_COMPOSITE => {
 

	
 
            },
 
            _ => unreachable!("encountered keyword '{}' in definition range", String::from_utf8_lossy(keyword)),
 
        };
 
        loop {
 
            let next = iter.next();
 
            if next.is_none() {
 
                return Ok(())
 
            }
 

	
 
        Ok(())
 
            // Token was not None, so peek_ident returns None if not an ident
 
            let ident = peek_ident(&module.source, &mut iter);
 
            match ident {
 
                Some(KW_STRUCT) => self.visit_struct_definition(module, &mut iter, ctx)?,
 
                Some(KW_ENUM) => self.visit_enum_definition(module, &mut iter, ctx)?,
 
                Some(KW_FUNCTION) => self.visit_function_definition(module, &mut iter, ctx)?,
 
                Some(KW_PRIMITIVE) | Some(KW_COMPOSITE) => self.visit_component_definition(module, &mut iter, ctx)?,
 
                _ => return Err(ParseError::new_error_str_at_pos(
 
                    &module.source, iter.last_valid_pos(),
 
                    "unexpected symbol, expected some kind of type or procedure definition"
 
                )),
 
            }
 
        }
 
    }
 

	
 
    fn visit_struct_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_STRUCT)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse struct definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.struct_fields.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let start_pos = iter.last_valid_pos();
 
                let parser_type = consume_parser_type(
 
                    source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope,
 
                    definition_id, false, 0
 
                )?;
 
                let field = consume_ident_interned(source, iter, ctx)?;
 
                Ok(StructFieldDefinition{
 
                    span: InputSpan::from_positions(start_pos, field.span.end),
 
                    field, parser_type
 
                })
 
            },
 
            &mut self.struct_fields, "a struct field", "a list of struct fields", None
 
        )?;
 

	
 
        // Transfer to preallocated definition
 
        let struct_def = ctx.heap[definition_id].as_struct_mut();
 
        struct_def.fields.clone_from(&self.struct_fields);
 
        self.struct_fields.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_enum_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_ENUM)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse enum definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.enum_variants.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let value = if iter.next() == Some(TokenKind::Equal) {
 
                    iter.consume();
 
                    let (variant_number, _) = consume_integer_literal(source, iter, &mut self.buffer)?;
 
                    EnumVariantValue::Integer(variant_number as i64) // TODO: @int
 
                } else {
 
                    EnumVariantValue::None
 
                };
 
                Ok(EnumVariantDefinition{ identifier, value })
 
            },
 
            &mut self.enum_variants, "an enum variant", "a list of enum variants", None
 
        )?;
 

	
 
        // Transfer to definition
 
        let enum_def = ctx.heap[definition_id].as_enum_mut();
 
        enum_def.variants.clone_from(&self.enum_variants);
 
        self.enum_variants.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_union_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_UNION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse union definition
 
        consume_polymorphic_vars_spilled(source, iter)?;
 
        debug_assert!(self.union_variants.is_empty());
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, source, iter,
 
            |source, iter| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let mut close_pos = identifier.span.end;
 
                let has_embedded = maybe_consume_comma_separated(
 
                    TokenKind::OpenParen, TokenKind::CloseParen, source, iter,
 
                    |source, iter| {
 
                        consume_parser_type(
 
                            source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
                            module_scope, definition_id, false, 0
 
                        )
 
                    },
 
                    &mut self.parser_types, "an embedded type", Some(&mut close_pos)
 
                )?;
 
                let value = if has_embedded {
 
                    UnionVariantValue::Embedded(self.parser_types.clone())
 
                } else {
 
                    UnionVariantValue::None
 
                };
 
                self.parser_types.clear();
 

	
 
                Ok(UnionVariantDefinition{
 
                    span: InputSpan::from_positions(identifier.span.begin, close_pos),
 
                    identifier,
 
                    value
 
                })
 
            },
 
            &mut self.union_variants, "a union variant", "a list of union variants", None
 
        )?;
 

	
 
        // Transfer to AST
 
        let union_def = ctx.heap[definition_id].as_union_mut();
 
        union_def.variants.clone_from(&self.union_variants);
 
        self.union_variants.clear();
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_function_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        consume_exact_ident(&module.source, iter, KW_FUNCTION)?;
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated DefinitionId
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse function's argument list
 
        let mut parameter_section = self.parameters.start_section();
 
        consume_parameter_list(
 
            source, iter, ctx, &mut self.parameters, poly_vars, module_scope, definition_id
 
            source, iter, ctx, &mut parameter_section, poly_vars, module_scope, definition_id
 
        )?;
 
        let parameters = self.parameters.clone();
 
        self.parameters.clear();
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume return types
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let mut open_curly_pos = iter.last_valid_pos();
 
        consume_comma_separated_until(
 
            TokenKind::OpenCurly, &module.source, iter,
 
            |source, iter| {
 
                consume_parser_type(source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope, definition_id, false)
 
                consume_parser_type(source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope, definition_id, false, 0)
 
            },
 
            &mut self.parser_types, "a return type", None
 
            &mut self.parser_types, "a return type", Some(&mut open_curly_pos)
 
        )?;
 
        let return_types = self.parser_types.clone();
 
        self.parser_types.clear();
 

	
 
        // TODO: @ReturnValues
 
        match return_types.len() {
 
            0 => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "expected a return type")),
 
            1 => {},
 
            _ => return Err(ParseError::new_error_str_at_pos(&module.source, open_curly_pos, "multiple return types are not (yet) allowed")),
 
        }
 

	
 
        // Consume block
 
        let body = self.consume_block_statement_without_leading_curly(module, iter, ctx, open_curly_pos)?;
 

	
 
        // Assign everything in the preallocated AST node
 
        let function = ctx.heap[definition_id].as_function_mut();
 
        function.return_types = return_types;
 
        function.parameters = parameters;
 
        function.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_component_definition(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(), ParseError> {
 
        let (_variant_text, _) = consume_any_ident(&module.source, iter)?;
 
        debug_assert!(variant_text == KW_PRIMITIVE || variant_text == KW_COMPOSITE);
 
        let (ident_text, _) = consume_ident(&module.source, iter)?;
 

	
 
        // Retrieve preallocated definition
 
        let module_scope = SymbolScope::Module(module.root_id);
 
        let definition_id = ctx.symbols.get_symbol_by_name_defined_in_scope(module_scope, ident_text)
 
            .unwrap().variant.as_definition().definition_id;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        // Parse component's argument list
 
        let mut parameter_section = self.parameters.start_section();
 
        consume_parameter_list(
 
            source, iter, ctx, &mut parameter_section, poly_vars, module_scope, definition_id
 
        )?;
 
        let parameters = parameter_section.into_vec();
 

	
 
        // Consume block
 
        let body = self.consume_block_statement(module, iter, ctx)?;
 

	
 
        // Assign everything in the AST node
 
        let component = ctx.heap[definition_id].as_component_mut();
 
        component.parameters = parameters;
 
        component.body = body;
 

	
 
        Ok(())
 
    }
 

	
 
    /// Consumes a block statement. If the resulting statement is not a block
 
    /// (e.g. for a shorthand "if (expr) single_statement") then it will be
 
    /// wrapped in one
 
    fn consume_block_or_wrapped_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        if Some(TokenKind::OpenCurly) == iter.next() {
 
            // This is a block statement
 
            self.consume_block_statement(module, iter, ctx)
 
        } else {
 
            // Not a block statement, so wrap it in one
 
            let mut statements = self.statements.start_section();
 
            let wrap_begin_pos = iter.last_valid_pos();
 
            self.consume_statement(module, iter, ctx, &mut statements)?;
 
            let wrap_end_pos = iter.last_valid_pos();
 

	
 
            debug_assert_eq!(statements.len(), 1);
 
            let statements = statements.into_vec();
 

	
 
            ctx.heap.alloc_block_statement(|this| BlockStatement{
 
                this,
 
                is_implicit: true,
 
                span: InputSpan::from_positions(wrap_begin_pos, wrap_end_pos), // TODO: @Span
 
                statements,
 
                parent_scope: None,
 
                relative_pos_in_parent: 0,
 
                locals: Vec::new(),
 
                labels: Vec::new()
 
            })
 
        }
 
    }
 

	
 
    /// Consumes a statement and returns a boolean indicating whether it was a
 
    /// block or not.
 
    fn consume_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<(StatementId, bool), ParseError> {
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let next = iter.next().expect("consume_statement has a next token");
 

	
 
        let mut was_block = false;
 
        let statement = if next == TokenKind::OpenCurly {
 
            was_block = true;
 
            self.consume_block_statement(module, iter, ctx)?.upcast()
 
        if next == TokenKind::OpenCurly {
 
            let id = self.consume_block_statement(module, iter, ctx)?;
 
            section.push(id.upcast());
 
        } else if next == TokenKind::Ident {
 
            let (ident, _) = consume_any_ident(source, iter)?;
 
            if ident == KW_STMT_IF {
 
                self.consume_if_statement(module, iter, ctx)?
 
                // Consume if statement and place end-if statement directly
 
                // after it.
 
                let id = self.consume_if_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_if = ctx.heap.alloc_end_if_statement(|this| EndIfStatement{
 
                    this, start_if: id, next: None
 
                });
 
                section.push(id.upcast());
 

	
 
                let if_stmt = &mut ctx.heap[id];
 
                if_stmt.end_if = Some(end_if);
 
            } else if ident == KW_STMT_WHILE {
 
                self.consume_while_statement(module, iter, ctx)?
 
                let id = self.consume_while_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_while = ctx.heap.alloc_end_while_statement(|this| EndWhileStatement{
 
                    this, start_while: id, next: None
 
                });
 
                section.push(id.upcast());
 

	
 
                let while_stmt = &mut ctx.heap[id];
 
                while_stmt.end_while = Some(end_while);
 
            } else if ident == KW_STMT_BREAK {
 
                self.consume_break_statement(module, iter, ctx)?
 
                let id = self.consume_break_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CONTINUE {
 
                self.consume_continue_statement(module, iter, ctx)?
 
                let id = self.consume_continue_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_SYNC {
 
                self.consume_synchronous_statement(module, iter, ctx)?
 
                let id = self.consume_synchronous_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 

	
 
                let end_sync = ctx.heap.alloc_end_synchronous_statement(|this| EndSynchronousStatement{
 
                    this, start_sync: id, next: None
 
                });
 

	
 
                let sync_stmt = &mut ctx.heap[id];
 
                sync_stmt.end_sync = Some(end_sync);
 
            } else if ident == KW_STMT_RETURN {
 
                self.consume_return_statement(module, iter, ctx)?
 
                let id = self.consume_return_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_GOTO {
 
                self.consume_goto_statement(module, iter, ctx)?
 
                let id = self.consume_goto_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_NEW {
 
                self.consume_new_statement(module, iter, ctx)?
 
                let id = self.consume_new_statement(module, iter, ctx)?;
 
                section.push(id.upcast());
 
            } else if ident == KW_STMT_CHANNEL {
 
                self.consume_channel_statement(module, iter, ctx)?
 
                let id = self.consume_channel_statement(module, iter, ctx)?;
 
                section.push(id.upcast().upcast());
 
            } else if iter.peek() == Some(TokenKind::Colon) {
 
                self.consume_labeled_statement(module, iter, ctx)?
 
                self.consume_labeled_statement(module, iter, ctx, section)?;
 
            } else {
 
                // Two fallback possibilities: the first one is a memory
 
                // declaration, the other one is to parse it as a regular
 
                // expression. This is a bit ugly
 
                if let Some((memory_stmt_id, assignment_stmt_id)) = self.maybe_consume_memory_statement(module, iter, ctx)? {
 
                    section.push(memory_stmt_id.upcast().upcast());
 
                    section.push(assignment_stmt_id.upcast());
 
                } else {
 
                // Attempt to parse as expression
 
                self.consume_expression_statement(module, iter, ctx)?
 
                    let id = self.consume_expression_statement(module, iter, ctx)?;
 
                    section.push(id.upcast());
 
                }
 
            }
 
        };
 

	
 
        return Ok((statement, was_block));
 
        return Ok(());
 
    }
 

	
 
    fn consume_block_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let open_span = consume_token(source, iter, TokenKind::OpenCurly)?;
 
        self.consume_block_statement_without_leading_curly(module, iter, ctx, open_span.begin)
 
    }
 

	
 
    fn consume_block_statement_without_leading_curly(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, open_curly_pos: InputPosition
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let mut statements = Vec::new();
 
        let mut next = iter.next();
 
        while next.is_some() && next != Some(TokenKind::CloseCurly) {
 

	
 
        }
 

	
 
        let mut block_span = consume_token(&module.source, iter, TokenKind::CloseCurly)?;
 
        block_span.begin = open_curly_pos;
 

	
 
        Ok(ctx.heap.alloc_block_statement(|this| BlockStatement{
 
            this,
 
            is_implicit: false,
 
            span: block_span,
 
            statements,
 
            parent_scope: None,
 
            relative_pos_in_parent: 0,
 
            locals: Vec::new(),
 
            labels: Vec::new(),
 
        }))
 
    }
 

	
 
    fn consume_if_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<IfStatementId, ParseError> {
 
        let if_span = consume_exact_ident(&module.source, iter, KW_STMT_IF)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let (true_body, was_block) = self.consume_statement(module, iter, ctx)?;
 
        let true_body = Self::wrap_in_block(ctx, true_body, was_block);
 
        let true_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        let false_body = if has_ident(source, iter, KW_STMT_ELSE) {
 
            iter.consume();
 
            let (false_body, was_block) = self.consume_statement(module, iter, ctx)?;
 
            Some(Self::wrap_in_block(ctx, false_body, was_block))
 
            let false_body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 
            Some(false_body)
 
        } else {
 
            None
 
        };
 

	
 
        Ok(ctx.heap.alloc_if_statement(|this| IfStatement{
 
            this,
 
            span: if_span,
 
            test,
 
            true_body,
 
            false_body,
 
            end_if: None,
 
        }))
 
    }
 

	
 
    fn consume_while_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<WhileStatementId, ParseError> {
 
        let while_span = consume_exact_ident(&module.source, iter, KW_STMT_WHILE)?;
 
        consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
        let test = self.consume_expression(module, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::CloseParen)?;
 
        let (body, was_block) = self.consume_statement(module, iter, ctx)?;
 
        let body = Self::wrap_in_block(ctx, body, was_block);
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_while_statement(|this| WhileStatement{
 
            this,
 
            span: while_span,
 
            test,
 
            body,
 
            end_while: None,
 
            in_sync: None,
 
        }))
 
    }
 

	
 
    fn consume_break_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<BreakStatementId, ParseError> {
 
        let break_span = consume_exact_ident(&module.source, iter, KW_STMT_BREAK)?;
 
        let label = if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_break_statement(|this| BreakStatement{
 
            this,
 
            span: break_span,
 
            label,
 
            target: None,
 
        }))
 
    }
 

	
 
    fn consume_continue_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ContinueStatementId, ParseError> {
 
        let continue_span = consume_exact_ident(&module.source, iter, KW_STMT_CONTINUE)?;
 
        let label=  if Some(TokenKind::Ident) == iter.next() {
 
            let label = consume_ident_interned(&module.source, iter, ctx)?;
 
            Some(label)
 
        } else {
 
            None
 
        };
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_continue_statement(|this| ContinueStatement{
 
            this,
 
            span: continue_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_synchronous_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<SynchronousStatementId, ParseError> {
 
        let synchronous_span = consume_exact_ident(&module.source, iter, KW_STMT_SYNC)?;
 
        let (body, was_block) = self.consume_statement(module, iter, ctx)?;
 
        let body = Self::wrap_in_block(ctx, body, was_block);
 
        let body = self.consume_block_or_wrapped_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_synchronous_statement(|this| SynchronousStatement{
 
            this,
 
            span: synchronous_span,
 
            body,
 
            end_sync: None,
 
            parent_scope: None,
 
        }))
 
    }
 

	
 
    fn consume_return_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ReturnStatementId, ParseError> {
 
        let return_span = consume_exact_ident(&module.source, iter, KW_STMT_RETURN)?;
 
        let mut scoped_section = self.expressions.start_section();
 

	
 
        consume_comma_separated_until(
 
            TokenKind::SemiColon, &module.source, iter,
 
            |source, iter| self.consume_expression(module, iter, ctx),
 
            &mut scoped_section, "a return expression", None
 
        )?;
 
        let expressions = scoped_section.into_vec();
 

	
 
        if expressions.is_empty() {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "expected at least one return value"));
 
        }
 

	
 
        Ok(ctx.heap.alloc_return_statement(|this| ReturnStatement{
 
            this,
 
            span: return_span,
 
            expressions
 
        }))
 
    }
 

	
 
    fn consume_goto_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<GotoStatementId, ParseError> {
 
        let goto_span = consume_exact_ident(&module.source, iter, KW_STMT_GOTO)?;
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 
        Ok(ctx.heap.alloc_goto_statement(|this| GotoStatement{
 
            this,
 
            span: goto_span,
 
            label,
 
            target: None
 
        }))
 
    }
 

	
 
    fn consume_new_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<NewStatementId, ParseError> {
 
        let new_span = consume_exact_ident(&module.source, iter, KW_STMT_NEW)?;
 

	
 
        // TODO: @Cleanup, should just call something like consume_component_expression-ish
 
        let start_pos = iter.last_valid_pos();
 
        let expression_id = self.consume_primary_expression(module, iter, ctx)?;
 
        let expression = &ctx.heap[expression_id];
 
        let mut valid = false;
 

	
 
        let mut call_id = CallExpressionId.new_invalid();
 
        if let Expression::Call(expression) = expression {
 
            if expression.method == Method::UserComponent {
 
                call_id = expression.this;
 
                valid = true;
 
            }
 
        }
 

	
 
        if !valid {
 
            return Err(ParseError::new_error_str_at_span(
 
                source, InputSpan::from_positions(start_pos, iter.last_valid_pos()),
 
                "expected a call to a component"
 
            ));
 
        }
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        debug_assert!(!call_id.is_invalid());
 
        Ok(ctx.heap.alloc_new_statement(|this| NewStatement{
 
            this,
 
            span: new_span,
 
            expression: call_id,
 
            next: None
 
        }))
 
    }
 

	
 
    fn consume_channel_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ChannelStatementId, ParseError> {
 
        // Consume channel specification
 
        let channel_span = consume_exact_ident(&module.source, iter, KW_STMT_CHANNEL)?;
 
        let channel_type = if Some(TokenKind::OpenAngle) = iter.next() {
 
            // Retrieve the type of the channel, we're cheating a bit here by
 
            // consuming the first '<' and setting the initial angle depth to 1
 
            // such that our final '>' will be consumed as well.
 
            iter.consume();
 
            consume_parser_type(
 
                &module.source, iter, &ctx.symbols, &ctx.heap,
 
                poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                true, 1
 
            )?
 
        } else {
 
            // Assume inferred
 
            ParserType{ elements: vec![ParserTypeElement{
 
                full_span: channel_span, // TODO: @Span fix
 
                variant: ParserTypeVariant::Inferred
 
            }]}
 
        };
 

	
 
        let from_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let to_identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        // Construct ports
 
        let from = ctx.heap.alloc_local(|this| Local{
 
            this,
 
            identifier: from_identifier,
 
            parser_type: channel_type.clone(),
 
            relative_pos_in_block: 0,
 
        });
 
        let to = ctx.heap.alloc_local(|this| Local{
 
            this,
 
            identifier: to_identifier,
 
            parser_type: channel_type,
 
            relative_pos_in_block: 0,
 
        });
 

	
 
        // Construct the channel
 
        Ok(ctx.heap.alloc_channel_statement(|this| ChannelStatement{
 
            this,
 
            span: channel_span,
 
            from, to,
 
            relative_pos_in_block: 0,
 
            next: None,
 
        }))
 
    }
 

	
 
    fn consume_labeled_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<LabeledStatementId, ParseError> {
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, section: &mut ScopedSection<StatementId>
 
    ) -> Result<(), ParseError> {
 
        let label = consume_ident_interned(&module.source, iter, ctx)?;
 
        consume_token(&module.source, iter, TokenKind::Colon)?;
 
        let (body, _) = self.consume_statement(module, iter, ctx)?;
 

	
 
        Ok(ctx.heap.alloc_labeled_statement(|this| LabeledStatement{
 
            this, label, body,
 
        // Not pretty: consume_statement may produce more than one statement.
 
        // The values in the section need to be in the correct order if some
 
        // kind of outer block is consumed, so we take another section, push
 
        // the expressions in that one, and then allocate the labeled statement.
 
        let mut inner_section = self.statements.start_section();
 
        self.consume_statement(module, iter, ctx, &mut inner_section)?;
 
        debug_assert!(inner_section.len() >= 1);
 

	
 
        let stmt_id = ctx.heap.alloc_labeled_statement(|this| LabeledStatement {
 
            this,
 
            label,
 
            body: *inner_section[0],
 
            relative_pos_in_block: 0,
 
            in_sync: None
 
        }))
 
            in_sync: None,
 
        });
 

	
 
        if inner_section.len() == 1 {
 
            // Produce the labeled statement pointing to the first statement.
 
            // This is by far the most common case.
 
            inner_section.forget();
 
            section.push(stmt_id.upcast());
 
        } else {
 
            // Produce the labeled statement using the first statement, and push
 
            // the remaining ones at the end.
 
            let inner_statements = inner_section.into_vec();
 
            section.push(stmt_id.upcast());
 
            for idx in 1..inner_statements.len() {
 
                section.push(inner_statements[idx])
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn maybe_consume_memory_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<Option<(MemoryStatementId, ExpressionStatementId)>, ParseError> {
 
        // This is a bit ugly. It would be nicer if we could somehow
 
        // consume the expression with a type hint if we do get a valid
 
        // type, but we don't get an identifier following it
 
        let iter_state = iter.save();
 
        let definition_id = self.cur_definition;
 
        let poly_vars = ctx.heap[definition_id].poly_vars();
 

	
 
        let parser_type = consume_parser_type(
 
            &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
            SymbolScope::Definition(definition_id), definition_id, true, 0
 
        );
 

	
 
        if let Ok(parser_type) = parser_type {
 
            if Some(TokenKind::Ident) == iter.next() {
 
                // Assume this is a proper memory statement
 
                let identifier = consume_ident_interned(&module.source, iter, ctx)?;
 
                let memory_span = InputSpan::from_positions(parser_type.elements[0].full_span.begin, identifier.span.end);
 
                let assign_span = consume_token(&module.source, iter, TokenKind::Equal)?;
 

	
 
                let initial_expr_begin_pos = iter.last_valid_pos();
 
                let initial_expr_id = self.consume_expression(module, iter, ctx)?;
 
                let initial_expr_end_pos = iter.last_valid_pos();
 
                consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
                // Allocate the memory statement with the variable
 
                let local_id = ctx.heap.alloc_local(|this| Local{
 
                    this,
 
                    identifier: identifier.clone(),
 
                    parser_type,
 
                    relative_pos_in_block: 0,
 
                });
 
                let memory_stmt_id = ctx.heap.alloc_memory_statement(|this| MemoryStatement{
 
                    this,
 
                    span: memory_span,
 
                    variable: local_id,
 
                    next: None
 
                });
 

	
 
                // Allocate the initial assignment
 
                let variable_expr_id = ctx.heap.alloc_variable_expression(|this| VariableExpression{
 
                    this,
 
                    identifier,
 
                    declaration: None,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: Default::default()
 
                });
 
                let assignment_expr_id = ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                    this,
 
                    span: assign_span,
 
                    left: variable_expr_id.upcast(),
 
                    operation: AssignmentOperator::Set,
 
                    right: initial_expr_id,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: Default::default(),
 
                });
 
                let assignment_stmt_id = ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
                    this,
 
                    span: InputSpan::from_positions(initial_expr_begin_pos, initial_expr_end_pos),
 
                    expression: assignment_expr_id.upcast(),
 
                    next: None,
 
                });
 

	
 
                return Ok(Some((memory_stmt_id, assignment_stmt_id)))
 
            }
 
        }
 

	
 
        // If here then one of the preconditions for a memory statement was not
 
        // met. So recover the iterator and return
 
        iter.load(iter_state);
 
        Ok(None)
 
    }
 

	
 
    fn consume_expression_statement(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionStatementId, ParseError> {
 
        let start_pos = iter.last_valid_pos();
 
        let expression = self.consume_expression(module, iter, ctx)?;
 
        let end_pos = iter.last_valid_pos();
 
        consume_token(&module.source, iter, TokenKind::SemiColon)?;
 

	
 
        Ok(ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
            this,
 
            span: InputSpan::from_positions(start_pos, end_pos),
 
            expression,
 
            next: None,
 
        }))
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression Parsing
 
    //--------------------------------------------------------------------------
 

	
 
    fn consume_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_assignment_expression(module, iter, ctx)
 
    }
 

	
 
    fn consume_assignment_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        // Utility to convert token into assignment operator
 
        fn parse_assignment_operator(token: Option<TokenKind>) -> Option<AssignmentOperator> {
 
            use TokenKind as TK;
 
            use AssignmentOperator as AO;
 

	
 
            if token.is_none() {
 
                return None
 
            }
 

	
 
            match token.unwrap() {
 
                TK::Equal               => Some(AO::Set),
 
                TK::StarEquals          => Some(AO::Multiplied),
 
                TK::SlashEquals         => Some(AO::Divided),
 
                TK::PercentEquals       => Some(AO::Remained),
 
                TK::PlusEquals          => Some(AO::Added),
 
                TK::MinusEquals         => Some(AO::Subtracted),
 
                TK::ShiftLeftEquals     => Some(AO::ShiftedLeft),
 
                TK::ShiftRightEquals    => Some(AO::ShiftedRight),
 
                TK::AndEquals           => Some(AO::BitwiseAnded),
 
                TK::CaretEquals         => Some(AO::BitwiseXored),
 
                TK::OrEquals            => Some(AO::BitwiseOred),
 
                _                       => None
 
            }
 
        }
 

	
 
        let expr = self.consume_conditional_expression(module, iter, ctx)?;
 
        if let Some(operation) = parse_assignment_operator(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let left = expr;
 
            let right = self.consume_expression(module, iter, ctx)?;
 

	
 
            Ok(ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast())
 
        } else {
 
            Ok(expr)
 
        }
 
    }
 

	
 
    fn consume_conditional_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let result = self.consume_concat_expression(module, iter, ctx)?;
 
        if let Some(TokenKind::Question) = iter.next() {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let test = result;
 
            let true_expression = self.consume_expression(module, iter, ctx)?;
 
            consume_token(source, iter, TokenKind::Colon)?;
 
            let false_expression = self.consume_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_conditional_expression(|this| ConditionalExpression{
 
                this, span, test, true_expression, false_expression,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast())
 
        } else {
 
            Ok(result)
 
        }
 
    }
 

	
 
    fn consume_concat_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::At) => Some(BinaryOperator::Concatenate),
 
                _ => None
 
            },
 
            Self::consume_logical_or_expression
 
        )
 
    }
 

	
 
    fn consume_logical_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OrOr) => Some(BinaryOperator::LogicalOr),
 
                _ => None
 
            },
 
            Self::consume_logical_and_expression
 
        )
 
    }
 

	
 
    fn consume_logical_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::AndAnd) => Some(BinaryOperator::LogicalAnd),
 
                _ => None
 
            },
 
            Self::consume_bitwise_or_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_or_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Or) => Some(BinaryOperator::BitwiseOr),
 
                _ => None
 
            },
 
            Self::consume_bitwise_xor_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_xor_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Caret) => Some(BinaryOperator::BitwiseXor),
 
                _ => None
 
            },
 
            Self::consume_bitwise_and_expression
 
        )
 
    }
 

	
 
    fn consume_bitwise_and_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::And) => Some(BinaryOperator::BitwiseAnd),
 
                _ => None
 
            },
 
            Self::consume_equality_expression
 
        )
 
    }
 

	
 
    fn consume_equality_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::EqualEqual) => Some(BinaryOperator::Equality),
 
                Some(TokenKind::NotEqual) => Some(BinaryOperator::Inequality),
 
                _ => None
 
            },
 
            Self::consume_relational_expression
 
        )
 
    }
 

	
 
    fn consume_relational_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::OpenAngle) => Some(BinaryOperator::LessThan),
 
                Some(TokenKind::CloseAngle) => Some(BinaryOperator::GreaterThan),
 
                Some(TokenKind::LessEquals) => Some(BinaryOperator::LessThanEqual),
 
                Some(TokenKind::GreaterEquals) => Some(BinaryOperator::GreaterThanEqual),
 
                _ => None
 
            },
 
            Self::consume_shift_expression
 
        )
 
    }
 

	
 
    fn consume_shift_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::ShiftLeft) => Some(BinaryOperator::ShiftLeft),
 
                Some(TokenKind::ShiftRight) => Some(BinaryOperator::ShiftRight),
 
                _ => None
 
            },
 
            Self::consume_add_or_subtract_expression
 
        )
 
    }
 

	
 
    fn consume_add_or_subtract_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Plus) => Some(BinaryOperator::Add),
 
                Some(TokenKind::Minus) => Some(BinaryOperator::Subtract),
 
                _ => None,
 
            },
 
            Self::consume_multiply_divide_or_modulus_expression
 
        )
 
    }
 

	
 
    fn consume_multiply_divide_or_modulus_expression(
 
        &mut self, module: &Module, iter: &mut Tokeniter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_generic_binary_expression(
 
            module, iter, ctx,
 
            |token| match token {
 
                Some(TokenKind::Star) => Some(BinaryOperator::Multiply),
 
                Some(TokenKind::Slash) => Some(BinaryOperator::Divide),
 
                Some(TokenKind::Percent) => Some(BinaryOperator::Remainder),
 
                _ => None
 
            },
 
            Self::consume_prefix_expression
 
        )
 
    }
 

	
 
    fn consume_prefix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn parse_prefix_token(token: Option<TokenKind>) -> Some(UnaryOperation) {
 
            use TokenKind as TK;
 
            use UnaryOperation as UO;
 
            match token {
 
                Some(TK::Plus) => Some(UO::Positive),
 
                Some(TK::Minus) => Some(UO::Negative),
 
                Some(TK::PlusPlus) => Some(UO::PreIncrement),
 
                Some(TK::MinusMinus) => Some(UO::PreDecrement),
 
                Some(TK::Tilde) => Some(UO::BitwiseNot),
 
                Some(TK::Exclamation) => Some(UO::LogicalNot),
 
                _ => None
 
            }
 
        }
 

	
 
        if let Some(operation) = parse_prefix_token(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this, span, operation, expression,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default()
 
            }).upcast())
 
        } else {
 
            self.consume_postfix_expression(module, iter, ctx)
 
        }
 
    }
 

	
 
    fn consume_postfix_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        fn has_matching_postfix_token(token: Option<TokenKind>) -> bool {
 
            use TokenKind as TK;
 

	
 
            if token.is_none() { return false; }
 
            match token.unwrap() {
 
                TK::PlusPlus | TK::MinusMinus | TK::OpenSquare | TK::Dot => true,
 
                _ => false
 
            }
 
        }
 

	
 
        let mut result = self.consume_primary_expression(module, iter, ctx)?;
 
        let mut next = iter.next();
 
        while has_matching_postfix_token(next) {
 
            let token = next.unwrap();
 
            let mut span = iter.next_span();
 
            iter.consume();
 

	
 
            if token == TokenKind::PlusPlus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperation::PostIncrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            } else if token == TokenKind::MinusMinus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperation::PostDecrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            } else if token == TokenKind::OpenSquare {
 
                let subject = result;
 
                let from_index = self.consume_expression(module, iter, ctx)?;
 

	
 
                // Check if we have an indexing or slicing operation
 
                next = iter.next();
 
                if Some(TokenKind::DotDot) = next {
 
                    iter.consume();
 

	
 
                    let to_index = self.consume_expression(module, iter, ctx)?;
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this, span, subject, from_index, to_index,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default()
 
                    }).upcast();
 
                } else if Some(TokenKind::CloseSquare) {
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, span, subject,
 
                        index: from_index,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default()
 
                    }).upcast();
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected ']' or '..'"
 
                    ));
 
                }
 
            } else {
 
                debug_assert_eq!(token, TokenKind::Dot);
 
                let subject = result;
 
                let (field_text, field_span) = consume_ident(&module.source, iter)?;
 
                let field = if field_text == b"length" {
 
                    Field::Length
 
                } else {
 
                    let value = ctx.pool.intern(field_text);
 
                    let identifier = Identifier{ value, span: field_span };
 
                    Field::Symbolic(FieldSymbolic{ identifier, definition: None, field_idx: 0 });
 
                };
 

	
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, span, subject, field,
 
                    parent: ExpressionParent::None,
 
                    concrete_type: ConcreteType::default()
 
                }).upcast();
 
            }
 

	
 
            next = iter.next();
 
        }
 

	
 
        Ok(result)
 
    }
 

	
 
    fn consume_primary_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        let next = iter.next();
 

	
 
        let result = if next == Some(TokenKind::OpenParen) {
 
            // Expression between parentheses
 
            iter.consume();
 
            let result = self.consume_expression(module, iter, ctx)?;
 
            consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
            result
 
        } else if next == Some(TokenKind::OpenCurly) {
 
            // Array literal
 
            let (start_pos, mut end_pos) = iter.next_positions();
 
            let mut scoped_section = self.expressions.start_section();
 
            consume_comma_separated(
 
                TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter,
 
                |source, iter| self.consume_expression(module, iter, ctx),
 
                &mut scoped_section, "an expression", "a list of expressions", Some(&mut end_pos)
 
            )?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this,
 
                span: InputSpan::from_positions(start_pos, end_pos),
 
                value: Literal::Array(scoped_section.into_vec()),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Integer) {
 
            let (literal, span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Integer(LiteralInteger{ unsigned_value: literal, negated: false }),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::String) {
 
            let span = consume_string_literal(&module.source, iter, &mut self.buffer)?;
 
            let interned = ctx.pool.intern(self.buffer.as_bytes());
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::String(interned),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Character) {
 
            let (character, span) = consume_character_literal(&module.source, iter)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Character(character),
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default(),
 
            }).upcast()
 
        } else if next == Some(TokenKind::Ident) {
 
            // May be a variable, a type instantiation or a function call. If we
 
            // have a single identifier that we cannot find in the type table
 
            // then we're going to assume that we're dealing with a variable.
 
            let ident_span = iter.next_span();
 
            let ident_text = module.source.section_at_span(ident_span);
 
            let symbol = ctx.symbols.get_symbol_by_name(SymbolScope::Module(module.root_id), ident_text);
 

	
 
            if symbol.is_some() {
 
                // The first bit looked like a symbol, so we're going to follow
 
                // that all the way through, assume we arrive at some kind of
 
                // function call or type instantiation
 
                use ParserTypeVariant as PTV;
 

	
 
                let symbol_scope = SymbolScope::Definition(self.cur_definition);
 
                let poly_vars = ctx.heap[self.cur_definition].poly_vars();
 
                let parser_type = consume_parser_type(
 
                    &module.source, iter, &ctx.symbols, &ctx.heap, poly_vars, symbol_scope,
 
                    self.cur_definition, true, 0
 
                )?;
 
                debug_assert!(!parser_type.elements.is_empty());
 
                match parser_type.elements[0].variant {
 
                    PTV::Definition(target_definition_id, _) => {
 
                        let definition = &ctx.heap[target_definition_id];
 
                        match definition {
 
                            Definition::Struct(_) => {
 
                                // Struct literal
 
                                let mut last_token = iter.last_valid_pos();
 
                                let mut struct_fields = Vec::new();
 
                                consume_comma_separated(
 
                                    TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter,
 
                                    |source, iter| {
 
                                        let identifier = consume_ident_interned(source, iter, ctx)?;
 
                                        consume_token(source, iter, TokenKind::Colon)?;
 
                                        let value = self.consume_expression(module, iter, ctx)?;
 
                                        Ok(LiteralStructField{ identifier, value, field_idx: 0 })
 
                                    },
 
                                    &mut struct_fields, "a struct field", "a list of struct field", Some(&mut last_token)
 
                                )?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, last_token),
 
                                    value: Literal::Struct(LiteralStruct{
 
                                        parser_type,
 
                                        fields: struct_fields,
 
                                        definition: target_definition_id,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            },
 
                            Definition::Enum(_) => {
 
                                // Enum literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, variant.span.end),
 
                                    value: Literal::Enum(LiteralEnum{
 
                                        parser_type,
 
                                        variant,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                }).upcast()
 
                            },
 
                            Definition::Union(_) => {
 
                                // Union literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                // Consume any possible embedded values
 
                                let mut end_pos = iter.last_valid_pos();
 
                                let values = self.consume_expression_list(module, iter, ctx, Some(&mut end_pos))?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, end_pos),
 
                                    value: Literal::Union(LiteralUnion{
 
                                        parser_type, variant, values,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                }).upcast()
 
                            },
 
                            Definition::Component(_) => {
 
                                // Component instantiation
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method: Method::UserComponent,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            },
 
                            Definition::Function(function_definition) => {
 
                                // Function call: consume the arguments
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                // Check whether it is a builtin function
 
                                let method = if function_definition.builtin {
 
                                    match function_definition.identifier.value.as_str() {
 
                                        "get" => Method::Get,
 
                                        "put" => Method::Put,
 
                                        "fires" => Method::Fires,
 
                                        "create" => Method::Create,
 
                                        "length" => Method::Length,
 
                                        "assert" => Method::Assert,
 
                                        _ => unreachable!(),
 
                                    }
 
                                } else {
 
                                    Method::UserFunction
 
                                };
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default(),
 
                                }).upcast()
 
                            }
 
                        }
 
                    },
 
                    _ => {
 
                        // TODO: Casting expressions
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, parser_type.elements[0].full_span,
 
                            "unexpected type in expression, note that casting expressions are not yet implemented"
 
                        ))
 
                    }
 
                }
 
            } else {
 
                // Check for builtin keywords or builtin functions
 
                if ident_text == KW_LIT_NULL || ident_text == KW_LIT_TRUE || ident_text == KW_LIT_FALSE {
 
                    // Parse builtin literal
 
                    let value = match ident_text {
 
                        KW_LIT_NULL => Literal::Null,
 
                        KW_LIT_TRUE => Literal::True,
 
                        KW_LIT_FALSE => Literal::False,
 
                        _ => unreachable!(),
 
                    };
 

	
 
                    ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                        this,
 
                        span: ident_span,
 
                        value,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default(),
 
                    }).upcast()
 
                } else {
 
                    // I'm a bit unsure about this. One may as well have wrongfully
 
                    // typed `TypeWithTypo<Subtype>::`, then we assume that
 
                    // `TypeWithTypo` is a variable. So might want to come back to
 
                    // this later to do some silly heuristics.
 
                    iter.consume();
 
                    if Some(TokenKind::ColonColon) == iter.next() {
 
                        return Err(ParseError::new_error_str_at_span(&module.source, ident_span, "unknown identifier"));
 
                    }
 

	
 
                    let ident_text = ctx.pool.intern(ident_text);
 
                    let identifier = Identifier { span: ident_span, value: ident_text };
 

	
 
                    ctx.heap.alloc_variable_expression(|this| VariableExpression {
 
                        this,
 
                        identifier,
 
                        declaration: NJone,
 
                        parent: ExpressionParent::None,
 
                        concrete_type: ConcreteType::default()
 
                    }).upcast()
 
                }
 
            }
 
        };
 

	
 
        Ok(result)
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression Utilities
 
    //--------------------------------------------------------------------------
 

	
 
    #[inline]
 
    fn consume_generic_binary_expression<
 
        M: Fn(Option<TokenKind>) -> Option<BinaryOperator>,
 
        F: Fn(&mut PassDefinitions, &Module, &mut TokenIter, &mut PassCtx) -> Result<ExpressionId, ParseError>
 
    >(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, match_fn: M, higher_precedence_fn: F
 
    ) -> Result<ExpressionId, ParseError> {
 
        let mut result = higher_precedence_fn(self, module, iter, ctx)?;
 
        while let Some(operation) = match_fn(iter.next()) {
 
            let span = iter.next_span();
 
            iter.consume();
 

	
 
            let left = result;
 
            let right = higher_precedence_fn(self, module, iter, ctx)?;
 

	
 
            result = ctx.heap.alloc_binary_expression(|this| BinaryExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                concrete_type: ConcreteType::default()
 
            }).upcast();
 
        }
 

	
 
        Ok(result)
 
    }
 

	
 
    #[inline]
 
    fn consume_expression_list(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, end_pos: Option<&mut InputPosition>
 
    ) -> Result<Vec<ExpressionId>, ParseError> {
 
        let mut section = self.expressions.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenParen, TokenKind::CloseParen, &module.source, iter,
 
            |source, iter| self.consume_expression(module, iter, ctx),
 
            &mut section, "an expression", "a list of expressions", end_pos
 
        )?;
 
        Ok(section.into_vec())
 
    }
 

	
 
    fn wrap_in_block(ctx: &mut PassCtx, statement: StatementId, was_block: bool) -> BlockStatementId {
 
        debug_assert_eq!(was_block, ctx.heap[statement].is_block());
 
        if was_block {
 
            return BlockStatementId(StatementId::new(statement.index)); // Yucky
 
        }
 

	
 
        ctx.heap.alloc_block_statement(|this| BlockStatement{
 
            this,
 
            is_implicit: true,
 
            span: ctx.heap[statement].span(),
 
            statements: vec![statement],
 
            parent_scope: None,
 
            relative_pos_in_parent: 0,
 
            locals: Vec::new(),
 
            labels: Vec::new(),
 
        })
 
    }
 
}
 

	
 
/// Consumes a type. A type always starts with an identifier which may indicate
 
/// a builtin type or a user-defined type. The fact that it may contain
 
/// polymorphic arguments makes it a tree-like structure. Because we cannot rely
 
/// on knowing the exact number of polymorphic arguments we do not check for
 
/// these.
 
///
 
/// Note that the first depth index is used as a hack.
 
// TODO: @Optimize, @Span fix
 
fn consume_parser_type(
 
    source: &InputSource, iter: &mut TokenIter, symbols: &SymbolTable, heap: &Heap, poly_vars: &[Identifier],
 
    cur_scope: SymbolScope, wrapping_definition: DefinitionId, allow_inference: bool, first_angle_depth: i32,
 
) -> Result<ParserType, ParseError> {
 
    struct Entry{
 
        element: ParserTypeElement,
 
        depth: i32,
 
    }
 

	
 
    fn insert_array_before(elements: &mut Vec<Entry>, depth: i32, span: InputSpan) {
 
        let index = elements.iter().rposition(|e| e.depth == depth).unwrap();
 
        elements.insert(index, Entry{
 
            element: ParserTypeElement{ full_span: span, variant: ParserTypeVariant::Array },
 
            depth,
 
        });
 
    }
 

	
 
    // Most common case we just have one type, perhaps with some array
 
    // annotations.
 
    let element = consume_parser_type_ident(source, iter, symbols, heap, poly_vars, cur_scope, wrapping_definition, allow_inference)?;
 
    if iter.next() != Some(TokenKind::OpenAngle) {
 
        let mut num_array = 0;
 
        while iter.next() == Some(TokenKind::OpenSquare) {
 
            iter.consume();
 
            consume_token(source, iter, TokenKind::CloseSquare)?;
 
            num_array += 1;
 
        }
 

	
 
        let array_span = element.full_span;
 
        let mut elements = Vec::with_capacity(num_array + 1);
 
        for _ in 0..num_array {
 
            elements.push(ParserTypeElement{ full_span: array_span, variant: ParserTypeVariant::Array });
 
        }
 
        elements.push(element);
 

	
 
        return Ok(ParserType{ elements });
 
    };
 

	
 
    // We have a polymorphic specification. So we start by pushing the item onto
 
    // our stack, then start adding entries together with the angle-brace depth
 
    // at which they're found.
 
    let mut elements = Vec::new();
 
    elements.push(Entry{ element, depth: 0 });
 

	
 
    // Start out with the first '<' consumed.
 
    iter.consume();
 
    enum State { Ident, Open, Close, Comma };
 
    let mut state = State::Open;
 
    let mut angle_depth = first_angle_depth + 1;
 

	
 
    loop {
 
        let next = iter.next();
 

	
 
        match state {
 
            State::Ident => {
 
                // Just parsed an identifier, may expect comma, angled braces,
 
                // or the tokens indicating an array
 
                if Some(TokenKind::OpenAngle) == next {
 
                    angle_depth += 1;
 
                    state = State::Open;
 
                } else if Some(TokenKind::CloseAngle) == next {
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    angle_depth -= 2;
 
                    state = State::Close;
 
                } else if Some(TokenKind::Comma) == next {
 
                    state = State::Comma;
 
                } else if Some(TokenKind::OpenSquare) == next {
 
                    let (start_pos, _) = iter.next_positions();
 
                    iter.consume(); // consume opening square
 
                    if iter.next() != Some(TokenKind::CloseSquare) {
 
                        return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected ']'"
 
                        ));
 
                    }
 
                    let (_, end_pos) = iter.next_positions();
 
                    let array_span = InputSpan::from_positions(start_pos, end_pos);
 
                    insert_array_before(&mut elements, angle_depth, array_span);
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        source, iter.last_valid_pos(),
 
                        "unexpected token: expected '<', '>', ',' or '['")
 
                    );
 
                }
 

	
 
                iter.consume();
 
            },
 
            State::Open => {
 
                // Just parsed an opening angle bracket, expecting an identifier
 
                let element = consume_parser_type_ident(source, iter, symbols, heap, poly_vars, cur_scope, wrapping_definition, allow_inference)?;
 
                elements.push(Entry{ element, depth: angle_depth });
 
                state = State::Ident;
 
            },
 
            State::Close => {
 
                // Just parsed 1 or 2 closing angle brackets, expecting comma,
 
                // more closing brackets or the tokens indicating an array
 
                if Some(TokenKind::Comma) == next {
 
                    state = State::Comma;
 
                } else if Some(TokenKind::CloseAngle) == next {
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    angle_depth -= 2;
 
                    state = State::Close;
 
                } else if Some(TokenKind::OpenSquare) == next {
 
                    let (start_pos, _) = iter.next_positions();
 
                    iter.consume();
 
                    if iter.next() != Some(TokenKind::CloseSquare) {
 
                        return Err(ParseError::new_error_str_at_pos(
 
                            source, iter.last_valid_pos(),
 
                            "unexpected token: expected ']'"
 
                        ));
 
                    }
 
                    let (_, end_pos) = iter.next_positions();
 
                    let array_span = InputSpan::from_positions(start_pos, end_pos);
 
                    insert_array_before(&mut elements, angle_depth, array_span);
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        source, iter.last_valid_pos(),
 
                        "unexpected token: expected ',', '>', or '['")
 
                    );
 
                }
 

	
 
                iter.consume();
 
            },
 
            State::Comma => {
 
                // Just parsed a comma, expecting an identifier or more closing
 
                // braces
 
                if Some(TokenKind::Ident) == next {
 
                    let element = consume_parser_type_ident(source, iter, symbols, heap, poly_vars, cur_scope, wrapping_definition, allow_inference)?;
 
                    elements.push(Entry{ element, depth: angle_depth });
 
                    state = State::Ident;
 
                } else if Some(TokenKind::CloseAngle) == next {
 
                    iter.consume();
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    iter.consume();
 
                    angle_depth -= 2;
 
                    state = State::Close;
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        source, iter.last_valid_pos(),
 
                        "unexpected token: expected '>' or a type name"
 
                    ));
 
                }
 
            }
 
        }
 

	
 
        if angle_depth < 0 {
 
            return Err(ParseError::new_error_str_at_pos(source, iter.last_valid_pos(), "unmatched '>'"));
 
        } else if angle_depth == 0 {
 
            break;
 
        }
 
    }
 

	
 
    // If here then we found the correct number of angle braces. But we still
 
    // need to make sure that each encountered type has the correct number of
 
    // embedded types.
 
    let mut idx = 0;
 
    while idx < elements.len() {
 
        let cur_element = &elements[idx];
 
        let expected_subtypes = cur_element.element.variant.num_embedded();
 
        let mut encountered_subtypes = 0;
 
        for peek_idx in idx + 1..elements.len() {
 
            let peek_element = &elements[peek_idx];
 
            if peek_element.depth == cur_element.depth + 1 {
 
                encountered_subtypes += 1;
 
            } else if peek_element.depth <= cur_element.depth {
 
                break;
 
            }
 
        }
 

	
 
        if expected_subtypes != encountered_subtypes {
 
            if encountered_subtypes == 0 {
 
                // Case where we have elided the embedded types, all of them
 
                // should be inferred.
 
                if !allow_inference {
 
                    return Err(ParseError::new_error_str_at_span(
 
                        source, cur_element.element.full_span,
 
                        "type inference is not allowed here"
 
                    ));
 
                }
 

	
 
                // Insert the missing types
 
                let inserted_span = cur_element.element.full_span;
 
                let inserted_depth = cur_element.depth + 1;
 
                elements.reserve(expected_subtypes);
 
                for _ in 0..expected_subtypes {
 
                    elements.insert(idx + 1, Entry{
 
                        element: ParserTypeElement{ full_span: inserted_span, variant: ParserTypeVariant::Inferred },
 
                        depth: inserted_depth,
 
                    });
 
                }
 
            } else {
 
                // Mismatch in number of embedded types
 
                let expected_args_text = if expected_subtypes == 1 {
 
                    "polymorphic argument"
 
                } else {
 
                    "polymorphic arguments"
 
                };
 

	
 
                let maybe_infer_text = if allow_inference {
 
                    " (or none, to perform implicit type inference)"
 
                } else {
 
                    ""
 
                };
 

	
 
                return Err(ParseError::new_error_at_span(
 
                    source, cur_element.element.full_span,
 
                    format!(
 
                        "expected {} {}{}, but {} were provided",
 
                        expected_subtypes, expected_args_text, maybe_infer_text, encountered_subtypes
 
                    )
 
                ));
 
            }
 
        }
 

	
 
        idx += 1;
 
    }
 

	
 
    let mut constructed_elements = Vec::with_capacity(elements.len());
 
    for element in elements.into_iter() {
 
        constructed_elements.push(element.element);
 
    }
 

	
 
    Ok(ParserType{ elements: constructed_elements })
 
}
 

	
 
/// Consumes an identifier for which we assume that it resolves to some kind of
 
/// type. Once we actually arrive at a type we will stop parsing. Hence there
 
/// may be trailing '::' tokens in the iterator.
 
fn consume_parser_type_ident(
 
    source: &InputSource, iter: &mut TokenIter, symbols: &SymbolTable, heap: &Heap, poly_vars: &[Identifier],
 
    mut scope: SymbolScope, wrapping_definition: DefinitionId, allow_inference: bool,
 
) -> Result<ParserTypeElement, ParseError> {
 
    use ParserTypeVariant as PTV;
 
    let (mut type_text, mut type_span) = consume_any_ident(source, iter)?;
 

	
 
    let variant = match type_text {
 
        KW_TYPE_MESSAGE => PTV::Message,
 
        KW_TYPE_BOOL => PTV::Bool,
 
        KW_TYPE_UINT8 => PTV::UInt8,
 
        KW_TYPE_UINT16 => PTV::UInt16,
 
        KW_TYPE_UINT32 => PTV::UInt32,
 
        KW_TYPE_UINT64 => PTV::UInt64,
 
        KW_TYPE_SINT8 => PTV::SInt8,
 
        KW_TYPE_SINT16 => PTV::SInt16,
 
        KW_TYPE_SINT32 => PTV::SInt32,
 
        KW_TYPE_SINT64 => PTV::SInt64,
 
        KW_TYPE_IN_PORT => PTV::Input,
 
        KW_TYPE_OUT_PORT => PTV::Output,
 
        KW_TYPE_CHAR => PTV::Character,
 
        KW_TYPE_STRING => PTV::String,
 
        KW_TYPE_INFERRED => {
 
            if !allow_inference {
 
                return Err(ParseError::new_error_str_at_span(source, type_span, "type inference is not allowed here"));
 
            }
 

	
 
            PTV::Inferred
 
        },
 
        _ => {
 
            // Must be some kind of symbolic type
 
            let mut type_kind = None;
 
            for (poly_idx, poly_var) in poly_vars.iter().enumerate() {
 
                if poly_var.value.as_bytes() == type_text {
 
                    type_kind = Some(PTV::PolymorphicArgument(wrapping_definition, poly_idx));
 
                }
 
            }
 

	
 
            if type_kind.is_none() {
 
                // Check symbol table for definition. To be fair, the language
 
                // only allows a single namespace for now. That said:
 
                let last_symbol = symbols.get_symbol_by_name(scope, type_text);
 
                if last_symbol.is_none() {
 
                    return Err(ParseError::new_error_str_at_span(source, type_span, "unknown type"));
 
                }
 
                let mut last_symbol = last_symbol.unwrap();
 

	
 
                loop {
 
                    match &last_symbol.variant {
 
                        SymbolVariant::Module(symbol_module) => {
 
                            // Expecting more identifiers
 
                            if Some(TokenKind::ColonColon) != iter.next() {
 
                                return Err(ParseError::new_error_str_at_span(source, type_span, "expected type but got module"));
 
                            }
 

	
 
                            consume_token(source, iter, TokenKind::ColonColon)?;
 

	
 
                            // Consume next part of type and prepare for next
 
                            // lookup loop
 
                            let (next_text, next_span) = consume_any_ident(source, iter)?;
 
                            let old_text = type_text;
 
                            type_text = next_text;
 
                            type_span.end = next_span.end;
 
                            scope = SymbolScope::Module(symbol_module.root_id);
 

	
 
                            let new_symbol = symbols.get_symbol_by_name_defined_in_scope(scope, type_text);
 
                            if new_symbol.is_none() {
 
                                return Err(ParseError::new_error_at_span(
 
                                    source, next_span,
 
                                    format!(
 
                                        "unknown type '{}' in module '{}'",
 
                                        String::from_utf8_lossy(type_text),
 
                                        String::from_utf8_lossy(old_text)
 
                                    )
 
                                ));
 
                            }
 

	
 
                            last_symbol = new_symbol.unwrap();
 
                        },
 
                        SymbolVariant::Definition(symbol_definition) => {
 
                            let num_poly_vars = heap[symbol_definition.definition_id].poly_vars().len();
 
                            type_kind = Some(PTV::Definition(symbol_definition.definition_id, num_poly_vars));
 
                            break;
 
                        }
 
                    }
 
                }
 
            }
 

	
 
            debug_assert!(type_kind.is_some());
 
            type_kind.unwrap()
 
        },
 
    };
 

	
 
    Ok(ParserTypeElement{ full_span: type_span, variant })
 
}
 

	
 
/// Consumes polymorphic variables and throws them on the floor.
 
fn consume_polymorphic_vars_spilled(source: &InputSource, iter: &mut TokenIter) -> Result<(), ParseError> {
 
    maybe_consume_comma_separated_spilled(
 
        TokenKind::OpenAngle, TokenKind::CloseAngle, source, iter,
 
        |source, iter| {
 
            consume_ident(source, iter)?;
 
            Ok(())
 
        }, "a polymorphic variable"
 
    )?;
 
    Ok(())
 
}
 

	
 
/// Consumes the parameter list to functions/components
 
fn consume_parameter_list(
 
    source: &InputSource, iter: &mut TokenIter, ctx: &mut PassCtx, target: &mut Vec<ParameterId>,
 
    source: &InputSource, iter: &mut TokenIter, ctx: &mut PassCtx, target: &mut ScopedSection<ParameterId>,
 
    poly_vars: &[Identifier], scope: SymbolScope, definition_id: DefinitionId
 
) -> Result<(), ParseError> {
 
    consume_comma_separated(
 
        TokenKind::OpenParen, TokenKind::CloseParen, source, iter,
 
        |source, iter| {
 
            let (start_pos, _) = iter.next_positions();
 
            let parser_type = consume_parser_type(
 
                source, iter, &ctx.symbols, &ctx.heap, poly_vars, scope,
 
                definition_id, false, 0
 
            )?;
 
            let identifier = consume_ident_interned(source, iter, ctx)?;
 
            let parameter_id = ctx.heap.alloc_parameter(|this| Parameter{
 
                this,
 
                span: InputSpan::from_positions(start_pos, identifier.span.end),
 
                parser_type,
 
                identifier
 
            });
 
            Ok(parameter_id)
 
        },
 
        target, "a parameter", "a parameter list", None
 
    )
 
}
 
\ No newline at end of file
src/protocol/parser/pass_imports.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::symbol_table2::*;
 
use super::{Module, ModuleCompilationPhase, PassCtx};
 
use super::tokens::*;
 
use super::token_parsing::*;
 
use crate::protocol::input_source2::{InputSource2 as InputSource, InputSpan, ParseError};
 
use crate::collections::*;
 

	
 
/// Parses all the imports in the module tokens. Is applied after the
 
/// definitions and name of modules are resolved. Hence we should be able to
 
/// resolve all symbols to their appropriate module/definition.
 
pub(crate) struct PassImport {
 
    imports: Vec<ImportId>,
 
    found_symbols: Vec<(AliasedSymbol, SymbolDefinition)>,
 
    scoped_symbols: Vec<Symbol>,
 
}
 

	
 
impl PassImport {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            imports: Vec::with_capacity(32),
 
            found_symbols: Vec::with_capacity(32),
 
            scoped_symbols: Vec::with_capacity(32),
 
        }
 
    }
 
    pub(crate) fn parse(&mut self, modules: &mut [Module], module_idx: usize, ctx: &mut PassCtx) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let module_range = &module.tokens.ranges[0];
 
        debug_assert!(modules.iter().all(|m| m.phase >= ModuleCompilationPhase::SymbolsScanned));
 
        debug_assert_eq!(module.phase, ModuleCompilationPhase::SymbolsScanned);
 
        debug_assert_eq!(module_range.range_kind, TokenRangeKind::Module);
 

	
 
        let mut range_idx = module_range.first_child_idx;
 
        loop {
 
            let range_idx_usize = range_idx as usize;
 
            let cur_range = &module.tokens.ranges[range_idx_usize];
 

	
 
            if cur_range.range_kind == TokenRangeKind::Import {
 
                self.visit_import_range(modules, module_idx, ctx, range_idx_usize)?;
 
            }
 

	
 
            match cur_range.next_sibling_idx {
 
                Some(idx) => { range_idx = idx; },
 
                None => { break; }
 
            }
 
        }
 

	
 
        let root = &mut ctx.heap[module.root_id];
 
        root.imports.extend(self.imports.drain(..));
 

	
 
        let module = &mut modules[module_idx];
 
        module.phase = ModuleCompilationPhase::ImportsResolved;
 

	
 
        Ok(())
 
    }
 

	
 
    pub(crate) fn visit_import_range(
 
        &mut self, modules: &mut [Module], module_idx: usize, ctx: &mut PassCtx, range_idx: usize
 
    ) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let import_range = &module.tokens.ranges[range_idx];
 
        debug_assert_eq!(import_range.range_kind, TokenRangeKind::Import);
 

	
 
        let mut iter = module.tokens.iter_range(import_range);
 

	
 
        // Consume "import"
 
        let (_import_ident, import_span) =
 
            consume_any_ident(&module.source, &mut iter)?;
 
        debug_assert_eq!(_import_ident, KW_IMPORT);
 

	
 
        // Consume module name
 
        let (module_name, module_name_span) = consume_domain_ident(&module.source, &mut iter)?;
 
        let target_root_id = ctx.symbols.get_module_by_name(module_name);
 
        if target_root_id.is_none() {
 
            return Err(ParseError::new_error_at_span(
 
                &module.source, module_name_span,
 
                format!("could not resolve module '{}'", String::from_utf8_lossy(module_name))
 
            ));
 
        }
 
        let module_name = ctx.pool.intern(module_name);
 
        let module_identifier = Identifier{ span: module_name_span, value: module_name };
 
        let target_root_id = target_root_id.unwrap();
 

	
 
        // Check for subsequent characters (alias, multiple imported symbols)
 
        let next = iter.next();
 
        let import_id;
 

	
 
        if has_ident(&module.source, &mut iter, b"as") {
 
            // Alias for module
 
            iter.consume();
 
            let alias_identifier = consume_ident_interned(&module.source, &mut iter, ctx)?;
 
            let alias_name = alias_identifier.value.clone();
 

	
 
            import_id = ctx.heap.alloc_import(|this| Import::Module(ImportModule{
 
                this,
 
                span: import_span,
 
                module: module_identifier,
 
                alias: alias_identifier,
 
                module_id: target_root_id
 
            }));
 
            ctx.symbols.insert_symbol(SymbolScope::Module(module.root_id), Symbol{
 
                name: alias_name,
 
                variant: SymbolVariant::Module(SymbolModule{
 
                    root_id: target_root_id,
 
                    introduced_at: import_id,
 
                }),
 
            });
 
        } else if Some(TokenKind::ColonColon) == next {
 
            iter.consume();
 

	
 
            // Helper function to consume symbols, their alias, and the
 
            // definition the symbol is pointing to.
 
            fn consume_symbol_and_maybe_alias<'a>(
 
                source: &'a InputSource, iter: &mut TokenIter, ctx: &mut PassCtx,
 
                module_name: &StringRef<'static>, module_root_id: RootId,
 
            ) -> Result<(AliasedSymbol, SymbolDefinition), ParseError> {
 
                // Consume symbol name and make sure it points to an existing definition
 
                let symbol_identifier = consume_ident_interned(source, iter, ctx)?;
 
                let target = ctx.symbols.get_symbol_by_name_defined_in_scope(
 
                    SymbolScope::Module(module_root_id), symbol
 
                );
 

	
 
                if target.is_none() {
 
                    return Err(ParseError::new_error_at_span(
 
                        source, symbol_span,
 
                        format!(
 
                            "could not find symbol '{}' within module '{}'",
 
                            symbol_identifier.value.as_str(), module_name.as_str()
 
                        )
 
                    ));
 
                }
 
                let target = target.unwrap();
 
                debug_assert_ne!(target.class(), SymbolClass::Module);
 
                let target_definition = target.variant.as_definition();
 

	
 
                // Consume alias text if specified
 
                let alias_identifier = if peek_ident(source, iter) == b"as" {
 
                    // Consume alias
 
                    iter.consume();
 
                    Some(consume_ident_interned(source, iter, ctx)?)
 
                } else {
 
                    None
 
                };
 

	
 
                Ok((
 
                    AliasedSymbol{
 
                        name: symbol_identifier,
 
                        alias: alias_identifier,
 
                        definition_id: target_definition.definition_id,
 
                    },
 
                    target_definition.clone()
 
                ))
 
            }
 

	
 
            let next = iter.next();
 

	
 
            if Some(TokenKind::Ident) = next {
 
                // Importing a single symbol
 
                iter.consume();
 
                let (imported_symbol, symbol_definition) = consume_symbol_and_maybe_alias(
 
                    &module.source, &mut iter, ctx, &module_identifier.value, target_root_id
 
                )?;
 
                let alias_identifier = imported_symbol.alias.unwrap_or_else(|| { imported_symbol.name.clone() });
 
                import_id = ctx.heap.alloc_import(|this| Import::Symbols(ImportSymbols{
 
                    this,
 
                    span: InputSpan::from_positions(import_span.begin, alias_identifier.span.end),
 
                    module: module_identifier,
 
                    module_id: target_root_id,
 
                    symbols: vec![imported_symbol],
 
                }));
 
                if let Err((new_symbol, old_symbol)) = ctx.symbols.insert_symbol(
 
                    SymbolScope::Module(module.root_id),
 
                    Symbol{
 
                        name: alias_identifier.value,
 
                        variant: SymbolVariant::Definition(symbol_definition.into_imported(import_id))
 
                    }
 
                ) {
 
                    return Err(construct_symbol_conflict_error(
 
                        modules, module_idx, ctx, &new_symbol, old_symbol
 
                    ));
 
                }
 
            } else if Some(TokenKind::OpenCurly) = next {
 
                // Importing multiple symbols
 
                let mut end_of_list = iter.last_valid_pos();
 
                consume_comma_separated(
 
                    TokenKind::OpenCurly, TokenKind::CloseCurly, source, &mut iter,
 
                    |source, iter| consume_symbol_and_maybe_alias(
 
                        source, iter, ctx, &module_identifier.value, target_root_id
 
                    ),
 
                    &mut self.found_symbols, "a symbol", "a list of symbols to import"
 
                    &mut self.found_symbols, "a symbol", "a list of symbols to import", Some(&mut end_of_list)
 
                )?;
 
                let end_of_list = iter.last_valid_pos();
 

	
 
                // Preallocate import
 
                import_id = ctx.heap.alloc_import(|this| Import::Symbols(ImportSymbols {
 
                    this,
 
                    span: InputSpan::from_positions(import_span.begin, end_of_list),
 
                    module: module_identifier,
 
                    module_id: target_root_id,
 
                    symbols: Vec::with_capacity(self.found_symbols.len()),
 
                }));
 

	
 
                // Fill import symbols while inserting symbols in the
 
                // appropriate scope in the symbol table.
 
                let import = ctx.heap[import_id].as_symbols_mut();
 

	
 
                for (imported_symbol, symbol_definition) in self.found_symbols.drain(..) {
 
                    let import_name = imported_symbol.alias.map_or_else(
 
                        || imported_symbol.name.value.clone(),
 
                        |v| v.value.clone()
 
                    );
 
                    import.symbols.push(imported_symbol);
 
                    if let Err((new_symbol, old_symbol)) = ctx.symbols.insert_symbol(
 
                        SymbolScope::Module(module.root_id), Symbol{
 
                            name: import_name,
 
                            variant: SymbolVariant::Definition(symbol_definition.into_imported(import_id))
 
                        }
 
                    ) {
 
                        return Err(construct_symbol_conflict_error(modules, module_idx, ctx, &new_symbol, old_symbol));
 
                    }
 
                }
 
            } else if Some(TokenKind::Star) = next {
 
                // Import all symbols from the module
 
                let star_span = iter.next_span();
 

	
 
                iter.consume();
 
                self.scoped_symbols.clear();
 
                let _found = ctx.symbols.get_all_symbols_defined_in_scope(
 
                    SymbolScope::Module(target_root_id),
 
                    &mut self.scoped_symbols
 
                );
 
                debug_assert!(_found); // even modules without symbols should have a scope
 

	
 
                // Preallocate import
 
                import_id = ctx.heap.alloc_import(|this| Import::Symbols(ImportSymbols{
 
                    this,
 
                    span: InputSpan::from_positions(import_span.begin, star_span.end),
 
                    module: module_identifier,
 
                    module_id: target_root_id,
 
                    symbols: Vec::with_capacity(self.scoped_symbols.len())
 
                }));
 

	
 
                // Fill import AST node and symbol table
 
                let import = ctx.heap[import_id].as_symbols_mut();
 

	
 
                for symbol in self.scoped_symbols.drain(..) {
 
                    let symbol_name = symbol.name;
 
                    match symbol.variant {
 
                        SymbolVariant::Definition(symbol_definition) => {
 
                            import.symbols.push(AliasedSymbol{
 
                                name: Identifier{ span: star_span, value: symbol.name.clone() },
 
                                alias: None,
 
                                definition_id: symbol_definition.definition_id,
 
                            });
 

	
 
                            if let Err((new_symbol, old_symbol)) = ctx.symbols.insert_symbol(
 
                                SymbolScope::Module(module.root_id),
 
                                Symbol{
 
                                    name: symbol_name,
 
                                    variant: SymbolVariant::Definition(symbol_definition.into_imported(import_id))
 
                                }
 
                            ) {
 
                                return Err(construct_symbol_conflict_error(modules, module_idx, ctx, &new_symbol, old_symbol));
 
                            }
 
                        },
 
                        _ => unreachable!(),
 
                    }
 
                }
 
            } else {
 
                return Err(ParseError::new_error_str_at_pos(
 
                    &module.source, iter.last_valid_pos(), "expected symbol name, '{' or '*'"
 
                ));
 
            }
 
        } else {
 
            // Assume implicit alias
 
            let module_name_str = module_identifier.value.clone();
 
            let last_ident_start = module_name_str.rfind('.').map_or(0, |v| v + 1);
 
            let alias_text = &module_name_str.as_bytes()[last_ident_start..];
 
            let alias = ctx.pool.intern(alias_text);
 
            let alias_span = InputSpan::from_positions(
 
                module_name_span.begin.with_offset(last_ident_start as u32),
 
                module_name_span.end
 
            );
 
            let alias_identifier = Identifier{ span: alias_span, value: alias.clone() };
 

	
 
            import_id = ctx.heap.alloc_import(|this| Import::Module(ImportModule{
 
                this,
 
                span: InputSpan::from_positions(import_span.begin, module_identifier.span.end),
 
                module: module_identifier,
 
                alias: alias_identifier,
 
                module_id: target_root_id,
 
            }));
 
            ctx.symbols.insert_symbol(SymbolScope::Module(module.root_id), Symbol{
 
                name: alias,
 
                variant: SymbolVariant::Module(SymbolModule{
 
                    root_id: target_root_id,
 
                    introduced_at: import_id
 
                })
 
            });
 
        }
 

	
 
        // By now the `import_id` is set, just need to make sure that the import
 
        // properly ends with a semicolon
 
        consume_token(&module.source, &mut iter, TokenKind::SemiColon)?;
 
        self.imports.push(import_id);
 

	
 
        Ok(())
 
    }
 
}
src/protocol/parser/pass_symbols.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::symbol_table2::*;
 
use crate::protocol::input_source2::{ParseError, InputSpan};
 
use super::tokens::*;
 
use super::token_parsing::*;
 
use super::{Module, ModuleCompilationPhase, PassCtx};
 

	
 
/// Scans the module and finds all module-level type definitions. These will be
 
/// added to the symbol table such that during AST-construction we know which
 
/// identifiers point to types. Will also parse all pragmas to determine module
 
/// names.
 
pub(crate) struct PassSymbols {
 
    symbols: Vec<Symbol>,
 
    pragmas: Vec<PragmaId>,
 
    imports: Vec<ImportId>,
 
    definitions: Vec<DefinitionId>,
 
    buffer: String,
 
    has_pragma_version: bool,
 
    has_pragma_module: bool,
 
}
 

	
 
impl PassSymbols {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            symbols: Vec::with_capacity(128),
 
            pragmas: Vec::with_capacity(8),
 
            imports: Vec::with_capacity(32),
 
            definitions: Vec::with_capacity(128),
 
            buffer: String::with_capacity(128),
 
            has_pragma_version: false,
 
            has_pragma_module: false,
 
        }
 
    }
 

	
 
    fn reset(&mut self) {
 
        self.symbols.clear();
 
        self.pragmas.clear();
 
        self.imports.clear();
 
        self.definitions.clear();
 
        self.has_pragma_version = false;
 
        self.has_pragma_module = false;
 
    }
 

	
 
    pub(crate) fn parse(&mut self, modules: &mut [Module], module_idx: usize, ctx: &mut PassCtx) -> Result<(), ParseError> {
 
        self.reset();
 

	
 
        let module = &mut modules[module_idx];
 
        let module_range = &module.tokens.ranges[0];
 

	
 
        debug_assert_eq!(module.phase, ModuleCompilationPhase::Tokenized);
 
        debug_assert_eq!(module_range.range_kind, TokenRangeKind::Module);
 
        debug_assert!(module.root_id.is_invalid()); // not set yet,
 

	
 
        // Preallocate root in the heap
 
        let root_id = ctx.heap.alloc_protocol_description(|this| {
 
            Root{
 
                this,
 
                pragmas: Vec::new(),
 
                imports: Vec::new(),
 
                definitions: Vec::new(),
 
            }
 
        });
 
        module.root_id = root_id;
 

	
 
        // Visit token ranges to detect definitions and pragmas
 
        let mut range_idx = module_range.first_child_idx;
 
        loop {
 
            let range_idx_usize = range_idx as usize;
 
            let cur_range = &module.tokens.ranges[range_idx_usize];
 

	
 
            // Parse if it is a definition or a pragma
 
            if cur_range.range_kind == TokenRangeKind::Definition {
 
                self.visit_definition_range(modules, module_idx, ctx, range_idx_usize)?;
 
            } else if cur_range.range_kind == TokenRangeKind::Pragma {
 
                self.visit_pragma_range(modules, module_idx, ctx, range_idx_usize)?;
 
            }
 

	
 
            match cur_range.next_sibling_idx {
 
                Some(idx) => { range_idx = idx; },
 
                None => { break; },
 
            }
 
        }
 

	
 
        // Add the module's symbol scope and the symbols we just parsed
 
        let module_scope = SymbolScope::Module(root_id);
 
        ctx.symbols.insert_scope(None, module_scope);
 
        for symbol in self.symbols.drain(..) {
 
            if let Err((new_symbol, old_symbol)) = ctx.symbols.insert_symbol(module_scope, symbol) {
 
                return Err(construct_symbol_conflict_error(modules, module_idx, ctx, &new_symbol, old_symbol))
 
            }
 
        }
 

	
 
        // Modify the preallocated root
 
        let root = &mut ctx.heap[root_id];
 
        root.pragmas.extend(self.pragmas.drain(..));
 
        root.definitions.extend(self.definitions.drain(..));
 
        module.phase = ModuleCompilationPhase::SymbolsScanned;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_pragma_range(&mut self, modules: &[Module], module_idx: usize, ctx: &mut PassCtx, range_idx: usize) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let range = &module.tokens.ranges[range_idx];
 
        let mut iter = module.tokens.iter_range(range);
 

	
 
        // Consume pragma name
 
        let (pragma_section, pragma_start, _) = consume_pragma(&self.source, &mut iter)?;
 

	
 
        // Consume pragma values
 
        if pragma_section == "#module" {
 
            // Check if name is defined twice within the same file
 
            if self.has_pragma_module {
 
                return Err(ParseError::new_error(&module.source, pragma_start, "module name is defined twice"));
 
            }
 

	
 
            // Consume the domain-name
 
            let (module_name, module_span) = consume_domain_ident(&module.source, &mut iter)?;
 
            if iter.next().is_some() {
 
                return Err(ParseError::new_error(&module.source, iter.last_valid_pos(), "expected end of #module pragma after module name"));
 
            }
 

	
 
            // Add to heap and symbol table
 
            let pragma_span = InputSpan::from_positions(pragma_start, module_span.end);
 
            let module_name = ctx.pool.intern(module_name);
 
            let pragma_id = ctx.heap.alloc_pragma(|this| Pragma::Module(PragmaModule{
 
                this,
 
                span: pragma_span,
 
                value: Identifier{ span: module_span, value: module_name.clone() },
 
            }));
 
            self.pragmas.push(pragma_id);
 

	
 
            if let Err(other_module_root_id) = ctx.symbols.insert_module(module_name, module.root_id) {
 
                // Naming conflict
 
                let this_module = &modules[module_idx];
 
                let other_module = seek_module(modules, other_module_root_id).unwrap();
 
                let (other_module_pragma_id, _) = other_module.name.unwrap();
 
                let other_pragma = ctx.heap[other_module_pragma_id].as_module();
 
                return Err(ParseError::new_error_str_at_span(
 
                    &this_module.source, pragma_span, "conflict in module name"
 
                ).with_info_str_at_span(
 
                    &other_module.source, other_pragma.span, "other module is defined here"
 
                ));
 
            }
 
            self.has_pragma_module = true;
 
        } else if pragma_section == "#version" {
 
            // Check if version is defined twice within the same file
 
            if self.has_pragma_version {
 
                return Err(ParseError::new_error(&module.source, pragma_start, "module version is defined twice"));
 
            }
 

	
 
            // Consume the version pragma
 
            let (version, version_span) = consume_integer_literal(&module.source, &mut iter, &mut self.buffer)?;
 
            let pragma_id = ctx.heap.alloc_pragma(|this| Pragma::Version(PragmaVersion{
 
                this,
 
                span: InputSpan::from_positions(pragma_start, version_span.end),
 
                version,
 
            }));
 
            self.pragmas.push(pragma_id);
 
            self.has_pragma_version = true;
 
        } else {
 
            // Custom pragma, maybe we support this in the future, but for now
 
            // we don't.
 
            return Err(ParseError::new_error(&module.source, pragma_start, "illegal pragma name"));
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_definition_range(&mut self, modules: &[Module], module_idx: usize, ctx: &mut PassCtx, range_idx: usize) -> Result<(), ParseError> {
 
        let module = &modules[module_idx];
 
        let range = &module.tokens.ranges[range_idx];
 
        let definition_span = InputSpan::from_positions(
 
            module.tokens.start_pos(range),
 
            module.tokens.end_pos(range)
 
        );
 
        let mut iter = module.tokens.iter_range(range);
 

	
 
        // First ident must be type of symbol
 
        let (kw_text, _) = consume_any_ident(&module.source, &mut iter).unwrap();
 

	
 
        // Retrieve identifier of definition
 
        let identifier = consume_ident_interned(&module.source, &mut iter, ctx)?;
 
        let mut poly_vars = Vec::new();
 
        maybe_consume_comma_separated(
 
            TokenKind::OpenAngle, TokenKind::CloseAngle, &module.source, &mut iter,
 
            |source, iter| consume_ident_interned(source, iter, ctx),
 
            &mut poly_vars, "a polymorphic variable"
 
            &mut poly_vars, "a polymorphic variable", None
 
        )?;
 
        let ident_text = identifier.value.clone(); // because we need it later
 

	
 
        // Reserve space in AST for definition and add it to the symbol table
 
        let definition_class;
 
        let ast_definition_id;
 
        match kw_text {
 
            KW_STRUCT => {
 
                let struct_def_id = ctx.heap.alloc_struct_definition(|this| {
 
                    StructDefinition::new_empty(this, definition_span, identifier, poly_vars)
 
                });
 
                definition_class = DefinitionClass::Struct;
 
                ast_definition_id = struct_def_id.upcast();
 
            },
 
            KW_ENUM => {
 
                let enum_def_id = ctx.heap.alloc_enum_definition(|this| {
 
                    EnumDefinition::new_empty(this, definition_span, identifier, poly_vars)
 
                });
 
                definition_class = DefinitionClass::Enum;
 
                ast_definition_id = enum_def_id.upcast();
 
            },
 
            KW_UNION => {
 
                let union_def_id = ctx.heap.alloc_union_definition(|this| {
 
                    UnionDefinition::new_empty(this, definition_span, identifier, poly_vars)
 
                });
 
                definition_class = DefinitionClass::Union;
 
                ast_definition_id = union_def_id.upcast()
 
            },
 
            KW_FUNCTION => {
 
                let func_def_id = ctx.heap.alloc_function_definition(|this| {
 
                    FunctionDefinition::new_empty(this, definition_span, identifier, poly_vars)
 
                });
 
                definition_class = DefinitionClass::Function;
 
                ast_definition_id = func_def_id.upcast();
 
            },
 
            KW_PRIMITIVE | KW_COMPOSITE => {
 
                let component_variant = if kw_text == KW_PRIMITIVE {
 
                    ComponentVariant::Primitive
 
                } else {
 
                    ComponentVariant::Composite
 
                };
 
                let comp_def_id = ctx.heap.alloc_component_definition(|this| {
 
                    ComponentDefinition::new_empty(this, definition_span, component_variant, identifier, poly_vars)
 
                });
 
                definition_class = DefinitionClass::Component;
 
                ast_definition_id = comp_def_id.upcast();
 
            },
 
            _ => unreachable!("encountered keyword '{}' in definition range", String::from_utf8_lossy(kw_text)),
 
        }
 

	
 
        let symbol = Symbol{
 
            name: ident_text,
 
            variant: SymbolVariant::Definition(SymbolDefinition{
 
                defined_in_module: module.root_id,
 
                defined_in_scope: SymbolScope::Module(module.root_id),
 
                definition_span,
 
                identifier_span,
 
                imported_at: None,
 
                class: definition_class,
 
                definition_id: ast_definition_id,
 
            }),
 
        };
 
        self.symbols.push(symbol);
 
        self.definitions.push(ast_definition_id);
 

	
 
        Ok(())
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/symbol_table2.rs
Show inline comments
 
/// symbol_table.rs
 
///
 
/// The datastructure used to lookup symbols within particular scopes. Scopes
 
/// may be module-level or definition level, although imports and definitions
 
/// within definitions are currently not allowed.
 
///
 
/// TODO: Once the compiler has matured, find out ways to optimize to prevent
 
///     the repeated HashMap lookup.
 

	
 
use std::collections::HashMap;
 
use std::collections::hash_map::Entry;
 

	
 
use crate::protocol::input_source2::*;
 
use crate::protocol::ast::*;
 
use crate::collections::*;
 

	
 
const RESERVED_SYMBOLS: usize = 32;
 

	
 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 
pub enum SymbolScope {
 
    Global,
 
    Module(RootId),
 
    Definition(DefinitionId),
 
}
 

	
 
#[derive(Clone, Copy, PartialEq, Eq)]
 
pub enum SymbolClass {
 
    Module,
 
    Struct,
 
    Enum,
 
    Union,
 
    Function,
 
    Component
 
}
 

	
 
#[derive(Clone, Copy, PartialEq, Eq)]
 
pub enum DefinitionClass {
 
    Struct,
 
    Enum,
 
    Union,
 
    Function,
 
    Component,
 
}
 

	
 
impl DefinitionClass {
 
    fn as_symbol_class(&self) -> SymbolClass {
 
        match self {
 
            DefinitionClass::Struct => SymbolClass::Struct,
 
            DefinitionClass::Enum => SymbolClass::Enum,
 
            DefinitionClass::Union => SymbolClass::Union,
 
            DefinitionClass::Function => SymbolClass::Function,
 
            DefinitionClass::Component => SymbolClass::Component,
 
        }
 
    }
 
}
 

	
 
struct ScopedSymbols {
 
    scope: SymbolScope,
 
    parent_scope: Option<SymbolScope>,
 
    child_scopes: Vec<SymbolScope>,
 
    symbols: Vec<Symbol>,
 
}
 

	
 
impl ScopedSymbols {
 
    fn get_symbol<'a>(&'a self, name: &StringRef) -> Option<&'a Symbol> {
 
        for symbol in self.symbols.iter() {
 
            if symbol.name == *name {
 
                return Some(symbol);
 
            }
 
        }
 

	
 
        None
 
    }
 
}
 

	
 
impl SymbolDefinition {
 
    pub fn symbol_class(&self) -> SymbolClass {
 
        use SymbolDefinition as SD;
 
        use SymbolClass as SC;
 

	
 
        match self {
 
            SD::Module(_) => SC::Module,
 
            SD::Struct(_) => SC::Struct,
 
            SD::Enum(_) => SC::Enum,
 
            SD::Union(_) => SC::Union,
 
            SD::Function(_) => SC::Function,
 
            SD::Component(_) => SC::Component,
 
        }
 
    }
 
}
 

	
 
#[derive(Debug)]
 
pub struct SymbolModule {
 
    pub root_id: RootId,
 
    pub introduced_at: ImportId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SymbolDefinition {
 
    // Definition location (not necessarily the place where the symbol
 
    // is introduced, as it may be imported). Builtin symbols will have invalid
 
    // spans and module IDs
 
    pub defined_in_module: RootId,
 
    pub defined_in_scope: SymbolScope,
 
    pub definition_span: InputSpan, // full span of definition
 
    pub identifier_span: InputSpan, // span of just the identifier
 
    // Location where the symbol is introduced in its scope
 
    pub imported_at: Option<ImportId>,
 
    // Definition in the heap, with a utility enum to determine its
 
    // class if the ID is not needed.
 
    pub class: DefinitionClass,
 
    pub definition_id: DefinitionId,
 
}
 

	
 
impl SymbolDefinition {
 
    /// Clones the entire data structure, but replaces the `imported_at` field
 
    /// with the supplied `ImportId`.
 
    pub(crate) fn into_imported(mut self, imported_at: ImportId) -> Self {
 
        self.imported_at = Some(imported_at);
 
        self
 
    }
 
}
 

	
 
#[derive(Debug)]
 
pub enum SymbolVariant {
 
    Module(SymbolModule),
 
    Definition(SymbolDefinition),
 
}
 

	
 
impl SymbolVariant {
 
    /// Returns the span at which the item was introduced. For an imported
 
    /// item (all modules, and imported types) this returns the span of the
 
    /// import. For a defined type this returns the span of the identifier
 
    pub(crate) fn span_of_introduction(&self, heap: &Heap) -> InputSpan {
 
        match self {
 
            SymbolVariant::Module(v) => heap[v.introduced_at].span(),
 
            SymbolVariant::Definition(v) => if let Some(import_id) = v.imported_at {
 
                heap[import_id].span()
 
            } else {
 
                v.identifier_span
 
            },
 
        }
 
    }
 

	
 
    pub(crate) fn as_module(&self) -> &SymbolModule {
 
        match self {
 
            SymbolVariant::Module(v) => v,
 
            SymbolVariant::Definition(_) => unreachable!("called 'as_module' on {:?}", self),
 
        }
 
    }
 

	
 
    pub(crate) fn as_definition(&self) -> &SymbolDefinition {
 
        match self {
 
            SymbolVariant::Module(v) => unreachable!("called 'as_definition' on {:?}", self),
 
            SymbolVariant::Definition(v) => v,
 
        }
 
    }
 

	
 
    pub(crate) fn as_definition_mut(&mut self) -> &mut SymbolDefinition {
 
        match self {
 
            SymbolVariant::Module(v) => unreachable!("called 'as_definition_mut' on {:?}", self),
 
            SymbolVariant::Definition(v) => v,
 
        }
 
    }
 
}
 

	
 
#[derive(Clone)]
 
pub struct Symbol {
 
    pub name: StringRef<'static>,
 
    pub variant: SymbolVariant,
 
}
 

	
 
impl Symbol {
 
    pub(crate) fn class(&self) -> SymbolClass {
 
        match &self.variant {
 
            SymbolVariant::Module(_) => SymbolClass::Module,
 
            SymbolVariant::Definition(data) => data.class.as_symbol_class(),
 
        }
 
    }
 
}
 

	
 
pub struct SymbolTable {
 
    module_lookup: HashMap<StringRef<'static>, RootId>,
 
    scope_lookup: HashMap<SymbolScope, ScopedSymbols>,
 
}
 

	
 
impl SymbolTable {
 
    /// Inserts a new module by its name. Upon module naming conflict the
 
    /// previously associated `RootId` will be returned.
 
    pub(crate) fn insert_module(&mut self, module_name: StringRef<'static>, root_id: RootId) -> Result<(), RootId> {
 
        match self.module_lookup.entry(module_name) {
 
            Entry::Occupied(v) => {
 
                Err(*v.get())
 
            },
 
            Entry::Vacant(v) => {
 
                v.insert(root_id);
 
                Ok(())
 
            }
 
        }
 
    }
 

	
 
    /// Retrieves module `RootId` by name
 
    pub(crate) fn get_module_by_name(&mut self, name: &[u8]) -> Option<RootId> {
 
        let string_ref = StringRef::new(name);
 
        self.module_lookup.get(&string_ref).map(|v| *v)
 
    }
 

	
 
    /// Inserts a new symbol scope. The parent must have been added to the
 
    /// symbol table before.
 
    pub(crate) fn insert_scope(&mut self, parent_scope: Option<SymbolScope>, new_scope: SymbolScope) {
 
        debug_assert!(
 
            parent_scope.is_none() || self.scope_lookup.contains_key(parent_scope.as_ref().unwrap()),
 
            "inserting scope {:?} but parent {:?} does not exist", new_scope, parent_scope
 
        );
 
        debug_assert!(!self.scope_lookup.contains_key(&new_scope), "inserting scope {:?}, but it already exists", new_scope);
 

	
 
        if let Some(parent_scope) = parent_scope {
 
            let parent = self.scope_lookup.get_mut(&parent_scope).unwrap();
 
            parent.child_scopes.push(new_scope);
 
        }
 

	
 
        let scope = ScopedSymbols {
 
            scope: new_scope,
 
            parent_scope,
 
            child_scopes: Vec::with_capacity(RESERVED_SYMBOLS),
 
            symbols: Vec::with_capacity(RESERVED_SYMBOLS)
 
        };
 
        self.scope_lookup.insert(new_scope, scope);
 
    }
 

	
 
    /// Inserts a symbol into a particular scope. The symbol's name may not
 
    /// exist in the scope or any of its parents. If it does collide then the
 
    /// symbol will be returned, together with the symbol that has the same
 
    /// name.
 
    pub(crate) fn insert_symbol(&mut self, in_scope: SymbolScope, symbol: Symbol) -> Result<(), (Symbol, &Symbol)> {
 
        debug_assert!(self.scope_lookup.contains_key(&in_scope), "inserting symbol {}, but scope {:?} does not exist", symbol.name.as_str(), in_scope);
 
        let mut seek_scope = in_scope;
 
        loop {
 
            let scoped_symbols = self.scope_lookup.get(&seek_scope).unwrap();
 
            for existing_symbol in scoped_symbols.symbols.iter() {
 
                if symbol.name == existing_symbol.name {
 
                    return Err((symbol, existing_symbol))
 
                }
 
            }
 

	
 
            match scoped_symbols.parent_scope {
 
                Some(parent_scope) => { seek_scope = parent_scope; },
 
                None => { break; }
 
            }
 
        }
 

	
 
        // If here, then there is no collision
 
        let scoped_symbols = self.scope_lookup.get_mut(&in_scope).unwrap();
 
        scoped_symbols.symbols.push(symbol);
 
        Ok(())
 
    }
 

	
 
    /// Retrieves a symbol by name by searching in a particular scope and that scope's parents. The
 
    /// returned symbol may both be imported as defined within any of the searched scopes.
 
    pub(crate) fn get_symbol_by_name(
 
        &self, mut in_scope: SymbolScope, name: &[u8]
 
    ) -> Option<&Symbol> {
 
        let string_ref = StringRef::new(name);
 
        loop {
 
            let scope = self.scope_lookup.get(&in_scope);
 
            if scope.is_none() {
 
                return None;
 
            }
 
            let scope = scope.unwrap();
 

	
 
            if let Some(symbol) = scope.get_symbol(&string_ref) {
 
                return Some(symbol);
 
            } else {
 
                // Could not find symbol in current scope, seek in the parent scope if it exists
 
                match &scope.parent_scope {
 
                    Some(parent_scope) => { in_scope = *parent_scope; },
 
                    None => return None,
 
                }
 
            }
 
        }
 
    }
 

	
 
    /// Retrieves a symbol by name by searching in a particular scope and that scope's parents. The
 
    /// returned symbol must be defined within any of the searched scopes and may not be imported.
 
    /// In case such an imported symbol exists then this function still returns `None`.
 
    pub(crate) fn get_symbol_by_name_defined_in_scope(
 
        &self, in_scope: SymbolScope, name: &[u8]
 
    ) -> Option<&Symbol> {
 
        match self.get_symbol_by_name(in_scope, name) {
 
            Some(symbol) => {
 
                match &symbol.variant {
 
                    SymbolVariant::Module(_) => {
 
                        None // in-scope modules are always imported
 
                    },
 
                    SymbolVariant::Definition(variant) => {
 
                        if variant.imported_at.is_some() || variant.defined_in_scope == SymbolScope::Global {
 
                            // Symbol is imported or lives in the global scope.
 
                            // Things in the global scope are defined by the
 
                            // compiler.
 
                            None
 
                        } else {
 
                            Some(symbol)
 
                        }
 
                    }
 
                }
 
            },
 
            None => None,
 
        }
 
    }
 

	
 
    /// Retrieves all symbols that are defined within a particular scope. Imported symbols are
 
    /// ignored. Returns `true` if the scope was found (which may contain 0 defined symbols) and
 
    /// `false` if the scope was not found.
 
    pub(crate) fn get_all_symbols_defined_in_scope(&self, in_scope: SymbolScope, target: &mut Vec<Symbol>) -> bool {
 
        match self.scope_lookup.get(&in_scope) {
 
            Some(scope) => {
 
                for symbol in &scope.symbols {
 
                    if let SymbolVariant::Definition(definition) = &symbol.variant {
 
                        if definition.imported_at.is_some() {
 
                            continue;
 
                        }
 

	
 
                        // Defined in scope, so push onto target
 
                        target.push(symbol.clone());
 
                    }
 
                }
 

	
 
                true
 
            },
 
            None => false,
 
        }
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/tokens.rs
Show inline comments
 
use crate::protocol::input_source2::{
 
    InputPosition2 as InputPosition,
 
    InputSpan
 
};
 

	
 
/// Represents a particular kind of token. Some tokens represent
 
/// variable-character tokens. Such a token is always followed by a
 
/// `TokenKind::SpanEnd` token.
 
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 
pub(crate) enum TokenKind {
 
    // Variable-character tokens, followed by a SpanEnd token
 
    Ident,          // regular identifier
 
    Pragma,         // identifier with prefixed `#`, range includes `#`
 
    Integer,        // integer literal
 
    String,         // string literal, range includes `"`
 
    Character,      // character literal, range includes `'`
 
    LineComment,    // line comment, range includes leading `//`, but not newline
 
    BlockComment,   // block comment, range includes leading `/*` and trailing `*/`
 
    // Punctuation (single character)
 
    Exclamation,    // !
 
    Question,       // ?
 
    Pound,          // #
 
    OpenAngle,      // <
 
    OpenCurly,      // {
 
    OpenParen,      // (
 
    OpenSquare,     // [
 
    CloseAngle,     // >
 
    CloseCurly,     // }
 
    CloseParen,     // )
 
    CloseSquare,    // ]
 
    Colon,          // :
 
    Comma,          // ,
 
    Dot,            // .
 
    SemiColon,      // ;
 
    Quote,          // '
 
    DoubleQuote,    // "
 
    // Operator-like (single character)
 
    At,             // @
 
    Plus,           // +
 
    Minus,          // -
 
    Star,           // *
 
    Slash,          // /
 
    Percent,        // %
 
    Caret,          // ^
 
    And,            // &
 
    Or,             // |
 
    Tilde,          // ~
 
    Equal,          // =
 
    // Punctuation (two characters)
 
    ColonColon,     // ::
 
    DotDot,         // ..
 
    ArrowRight,     // ->
 
    // Operator-like (two characters)
 
    PlusPlus,       // ++
 
    PlusEquals,     // +=
 
    MinusMinus,     // --
 
    MinusEquals,    // -=
 
    StarEquals,     // *=
 
    SlashEquals,    // /=
 
    PercentEquals,  // %=
 
    CaretEquals,    // ^=
 
    AndAnd,         // &&
 
    AndEquals,      // &=
 
    OrOr,           // ||
 
    OrEquals,       // |=
 
    EqualEqual,     // ==
 
    NotEqual,       // !=
 
    ShiftLeft,      // <<
 
    LessEquals,     // <=
 
    ShiftRight,     // >>
 
    GreaterEquals,  // >=
 
    // Operator-like (three characters)
 
    ShiftLeftEquals,// <<=
 
    ShiftRightEquals, // >>=
 
    // Special marker token to indicate end of variable-character tokens
 
    SpanEnd,
 
}
 

	
 
impl TokenKind {
 
    /// Returns true if the next expected token is the special `TokenKind::SpanEnd` token. This is
 
    /// the case for tokens of variable length (e.g. an identifier).
 
    fn has_span_end(&self) -> bool {
 
        return *self <= TokenKind::BlockComment
 
    }
 

	
 
    /// Returns the number of characters associated with the token. May only be called on tokens
 
    /// that do not have a variable length.
 
    fn num_characters(&self) -> u32 {
 
        debug_assert!(!self.has_span_end() && *self != TokenKind::SpanEnd);
 
        if *self <= TokenKind::Equal {
 
            1
 
        } else if *self <= TokenKind::ShiftRight {
 
            2
 
        } else {
 
            3
 
        }
 
    }
 

	
 
    /// Returns the characters that are represented by the token, may only be called on tokens that
 
    /// do not have a variable length.
 
    pub fn token_chars(&self) -> &'static str {
 
        debug_assert!(!self.has_span_end() && *self != TokenKind::SpanEnd);
 
        use TokenKind as TK;
 
        match self {
 
            TK::Exclamation => "!",
 
            TK::Question => "?",
 
            TK::Pound => "#",
 
            TK::OpenAngle => "<",
 
            TK::OpenCurly => "{",
 
            TK::OpenParen => "(",
 
            TK::OpenSquare => "[",
 
            TK::CloseAngle => ">",
 
            TK::CloseCurly => "}",
 
            TK::CloseParen => ")",
 
            TK::CloseSquare => "]",
 
            TK::Colon => ":",
 
            TK::Comma => ",",
 
            TK::Dot => ".",
 
            TK::SemiColon => ";",
 
            TK::Quote => "'",
 
            TK::DoubleQuote => "\"",
 
            TK::At => "@",
 
            TK::Plus => "+",
 
            TK::Minus => "-",
 
            TK::Star => "*",
 
            TK::Slash => "/",
 
            TK::Percent => "%",
 
            TK::Caret => "^",
 
            TK::And => "&",
 
            TK::Or => "|",
 
            TK::Tilde => "~",
 
            TK::Equal => "=",
 
            TK::ColonColon => "::",
 
            TK::DotDot => "..",
 
            TK::ArrowRight => "->",
 
            TK::PlusPlus => "++",
 
            TK::PlusEquals => "+=",
 
            TK::MinusMinus => "--",
 
            TK::MinusEquals => "-=",
 
            TK::StarEquals => "*=",
 
            TK::SlashEquals => "/=",
 
            TK::PercentEquals => "%=",
 
            TK::CaretEquals => "^=",
 
            TK::AndAnd => "&&",
 
            TK::AndEquals => "&=",
 
            TK::OrOr => "||",
 
            TK::OrEquals => "|=",
 
            TK::EqualEqual => "==",
 
            TK::NotEqual => "!=",
 
            TK::ShiftLeft => "<<",
 
            TK::LessEquals => "<=",
 
            TK::ShiftRight => ">>",
 
            TK::GreaterEquals => ">=",
 
            TK::ShiftLeftEquals => "<<=",
 
            TK::ShiftRightEquals => ">>=",
 
            // Lets keep these in explicitly for now, in case we want to add more symbols
 
            TK::Ident | TK::Pragma | TK::Integer | TK::String | TK::Character |
 
            TK::LineComment | TK::BlockComment | TK::SpanEnd => unreachable!(),
 
        }
 
    }
 
}
 

	
 
/// Represents a single token at a particular position.
 
pub(crate) struct Token {
 
    pub kind: TokenKind,
 
    pub pos: InputPosition,
 
}
 

	
 
impl Token {
 
    pub(crate) fn new(kind: TokenKind, pos: InputPosition) -> Self {
 
        Self{ kind, pos }
 
    }
 
}
 

	
 
/// The kind of token ranges that are specially parsed by the tokenizer.
 
#[derive(Debug, PartialEq, Eq)]
 
pub(crate) enum TokenRangeKind {
 
    Module,
 
    Pragma,
 
    Import,
 
    Definition,
 
    Code,
 
}
 

	
 
/// A range of tokens with a specific meaning. Such a range is part of a tree
 
/// where each parent tree envelops all of its children.
 
#[derive(Debug)]
 
pub(crate) struct TokenRange {
 
    // Index of parent in `TokenBuffer.ranges`, does not have a parent if the
 
    // range kind is Module, in that case the parent index points to itself.
 
    pub parent_idx: usize,
 
    pub range_kind: TokenRangeKind,
 
    pub curly_depth: u32,
 
    // Offsets into `TokenBuffer.ranges`: the tokens belonging to this range.
 
    pub start: u32,             // first token (inclusive index)
 
    pub end: u32,               // last token (exclusive index)
 
    // Child ranges
 
    pub num_child_ranges: u32,  // Number of subranges
 
    pub first_child_idx: u32,   // First subrange (or points to self if no subranges)
 
    pub last_child_idx: u32,    // Last subrange (or points to self if no subranges)
 
    pub next_sibling_idx: Option<u32>,
 
}
 

	
 
pub(crate) struct TokenBuffer {
 
    pub tokens: Vec<Token>,
 
    pub ranges: Vec<TokenRange>,
 
}
 

	
 
impl TokenBuffer {
 
    pub(crate) fn new() -> Self {
 
        Self{ tokens: Vec::new(), ranges: Vec::new() }
 
    }
 

	
 
    pub(crate) fn iter_range<'a>(&'a self, range: &TokenRange) -> TokenIter<'a> {
 
        TokenIter::new(self, range.start as usize, range.end as usize)
 
    }
 

	
 
    pub(crate) fn start_pos(&self, range: &TokenRange) -> InputPosition {
 
        self.tokens[range.start].pos
 
    }
 

	
 
    pub(crate) fn end_pos(&self, range: &TokenRange) -> InputPosition {
 
        let last_token = &self.tokens[range.end - 1];
 
        if last_token.kind == TokenKind::SpanEnd {
 
            return last_token.pos
 
        } else {
 
            debug_assert!(!last_token.kind.has_span_end());
 
            return last_token.pos.with_offset(last_token.kind.num_characters());
 
        }
 
    }
 
}
 

	
 
/// Iterator over tokens within a specific `TokenRange`.
 
pub(crate) struct TokenIter<'a> {
 
    tokens: &'a Vec<Token>,
 
    cur: usize,
 
    end: usize,
 
}
 

	
 
impl<'a> TokenIter<'a> {
 
    fn new(buffer: &'a TokenBuffer, start: usize, end: usize) -> Self {
 
        Self{ tokens: &buffer.tokens, cur: start, end }
 
    }
 

	
 
    /// Returns the next token (may include comments), or `None` if at the end
 
    /// of the range.
 
    pub(crate) fn next_including_comments(&self) -> Option<TokenKind> {
 
        if self.cur >= self.end {
 
            return None;
 
        }
 

	
 
        let token = &self.tokens[self.cur];
 
        Some(token.kind)
 
    }
 

	
 
    /// Returns the next token (but skips over comments), or `None` if at the
 
    /// end of the range
 
    pub(crate) fn next(&mut self) -> Option<TokenKind> {
 
        while let Some(token_kind) = self.next_including_comments() {
 
            if token_kind != TokenKind::LineComment && token_kind != TokenKind::BlockComment {
 
                return Some(token_kind);
 
            }
 
            self.consume();
 
        }
 

	
 
        return None
 
    }
 

	
 
    /// Peeks ahead by one token (i.e. the one that comes after `next()`), and
 
    /// skips over comments
 
    pub(crate) fn peek(&self) -> Option<TokenKind> {
 
        for next_idx in self.cur + 1..self.end {
 
            let next_kind = self.tokens[next_idx].kind;
 
            if next_kind != TokenKind::LineComment && next_kind != TokenKind::BlockComment && next_kind != TokenKind::SpanEnd {
 
                return Some(next_kind);
 
            }
 
        }
 

	
 
        return None;
 
    }
 

	
 
    /// Returns the start position belonging to the token returned by `next`. If
 
    /// there is not a next token, then we return the end position of the
 
    /// previous token.
 
    pub(crate) fn last_valid_pos(&self) -> InputPosition {
 
        if self.cur < self.end {
 
            // Return token position
 
            return self.tokens[self.cur].pos
 
        }
 

	
 
        // Return previous token end
 
        let token = &self.tokens[self.cur - 1];
 
        return if token.kind == TokenKind::SpanEnd {
 
            token.pos
 
        } else {
 
            token.pos.with_offset(token.kind.num_characters());
 
        };
 
    }
 

	
 
    /// Returns the token range belonging to the token returned by `next`. This
 
    /// assumes that we're not at the end of the range we're iterating over.
 
    /// TODO: @cleanup Phase out?
 
    pub(crate) fn next_positions(&self) -> (InputPosition, InputPosition) {
 
        debug_assert!(self.cur < self.end);
 
        let token = &self.tokens[self.cur];
 
        if token.kind.has_span_end() {
 
            let span_end = &self.tokens[self.cur + 1];
 
            debug_assert_eq!(span_end.kind, TokenKind::SpanEnd);
 
            (token.pos, span_end.pos)
 
        } else {
 
            let offset = token.kind.num_characters();
 
            (token.pos, token.pos.with_offset(offset))
 
        }
 
    }
 

	
 
    /// See `next_positions`
 
    pub(crate) fn next_span(&self) -> InputSpan {
 
        let (begin, end) = self.next_positions();
 
        return InputSpan::from_positions(begin, end)
 
    }
 

	
 
    /// Advances the iterator to the next (meaningful) token.
 
    pub(crate) fn consume(&mut self) {
 
        if let Some(kind) = self.next() {
 
            if kind.has_span_end() {
 
                self.cur += 2;
 
            } else {
 
                self.cur += 1;
 
            }
 
        }
 
    }
 

	
 
    /// Saves the current iteration position, may be passed to `load` to return
 
    /// the iterator to a previous position.
 
    pub(crate) fn save(&self) -> (usize, usize) {
 
        (self.cur, self.end)
 
    }
 

	
 
    pub(crate) fn load(&mut self, saved: (usize, usize)) {
 
        self.cur = saved.0;
 
        self.end = saved.1;
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/type_table.rs
Show inline comments
 
/**
 
TypeTable
 

	
 
Contains the type table: a datastructure that, when compilation succeeds,
 
contains a concrete type definition for each AST type definition. In general
 
terms the type table will go through the following phases during the compilation
 
process:
 

	
 
1. The base type definitions are resolved after the parser phase has
 
    finished. This implies that the AST is fully constructed, but not yet
 
    annotated.
 
2. With the base type definitions resolved, the validation/linker phase will
 
    use the type table (together with the symbol table) to disambiguate
 
    terms (e.g. does an expression refer to a variable, an enum, a constant,
 
    etc.)
 
3. During the type checking/inference phase the type table is used to ensure
 
    that the AST contains valid use of types in expressions and statements.
 
    At the same time type inference will find concrete instantiations of
 
    polymorphic types, these will be stored in the type table as monomorphed
 
    instantiations of a generic type.
 
4. After type checking and inference (and possibly when constructing byte
 
    code) the type table will construct a type graph and solidify each
 
    non-polymorphic type and monomorphed instantiations of polymorphic types
 
    into concrete types.
 

	
 
So a base type is defined by its (optionally polymorphic) representation in the
 
AST. A concrete type has concrete types for each of the polymorphic arguments. A
 
struct, enum or union may have polymorphic arguments but not actually be a
 
polymorphic type. This happens when the polymorphic arguments are not used in
 
the type definition itself. Similarly for functions/components: but here we just
 
check the arguments/return type of the signature.
 

	
 
Apart from base types and concrete types, we also use the term "embedded type"
 
for types that are embedded within another type, such as a type of a struct
 
struct field or of a union variant. Embedded types may themselves have
 
polymorphic arguments and therefore form an embedded type tree.
 

	
 
NOTE: for now a polymorphic definition of a function/component is illegal if the
 
    polymorphic arguments are not used in the arguments/return type. It should
 
    be legal, but we disallow it for now.
 

	
 
TODO: Allow potentially cyclic datatypes and reject truly cyclic datatypes.
 
TODO: Allow for the full potential of polymorphism
 
TODO: Detect "true" polymorphism: for datatypes like structs/enum/unions this
 
    is simple. For functions we need to check the entire body. Do it here? Or
 
    do it somewhere else?
 
TODO: Do we want to check fn argument collision here, or in validation phase?
 
TODO: Make type table an on-demand thing instead of constructing all base types.
 
TODO: Cleanup everything, feels like a lot can be written cleaner and with less
 
    assumptions on each function call.
 
// TODO: Review all comments
 
*/
 

	
 
use std::fmt::{Formatter, Result as FmtResult};
 
use std::collections::{HashMap, VecDeque};
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::parser::symbol_table::{SymbolTable, Symbol};
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::symbol_table2::{SymbolTable, Symbol, SymbolScope};
 
use crate::protocol::input_source2::{InputSource2 as InputSource, ParseError};
 
use crate::protocol::parser::*;
 

	
 
//------------------------------------------------------------------------------
 
// Defined Types
 
//------------------------------------------------------------------------------
 

	
 
#[derive(Copy, Clone, PartialEq, Eq)]
 
pub enum TypeClass {
 
    Enum,
 
    Union,
 
    Struct,
 
    Function,
 
    Component
 
}
 

	
 
impl TypeClass {
 
    pub(crate) fn display_name(&self) -> &'static str {
 
        match self {
 
            TypeClass::Enum => "enum",
 
            TypeClass::Union => "union",
 
            TypeClass::Struct => "struct",
 
            TypeClass::Function => "function",
 
            TypeClass::Component => "component",
 
        }
 
    }
 

	
 
    pub(crate) fn is_data_type(&self) -> bool {
 
        *self == TypeClass::Enum || *self == TypeClass::Union || *self == TypeClass::Struct
 
    }
 

	
 
    pub(crate) fn is_proc_type(&self) -> bool {
 
        *self == TypeClass::Function || *self == TypeClass::Component
 
    }
 
}
 

	
 
impl std::fmt::Display for TypeClass {
 
    fn fmt(&self, f: &mut Formatter<'_>) -> FmtResult {
 
        write!(f, "{}", self.display_name())
 
    }
 
}
 

	
 
/// Struct wrapping around a potentially polymorphic type. If the type does not
 
/// have any polymorphic arguments then it will not have any monomorphs and
 
/// `is_polymorph` will be set to `false`. A type with polymorphic arguments
 
/// only has `is_polymorph` set to `true` if the polymorphic arguments actually
 
/// appear in the types associated types (function return argument, struct
 
/// field, enum variant, etc.). Otherwise the polymorphic argument is just a
 
/// marker and does not influence the bytesize of the type.
 
pub struct DefinedType {
 
    pub(crate) ast_root: RootId,
 
    pub(crate) ast_definition: DefinitionId,
 
    pub(crate) definition: DefinedTypeVariant,
 
    pub(crate) poly_vars: Vec<PolyVar>,
 
    pub(crate) poly_vars: Vec<PolymorphicVariable>,
 
    pub(crate) is_polymorph: bool,
 
    pub(crate) is_pointerlike: bool,
 
    // TODO: @optimize
 
    pub(crate) monomorphs: Vec<Vec<ConcreteType>>,
 
}
 

	
 
impl DefinedType {
 
    fn add_monomorph(&mut self, types: Vec<ConcreteType>) {
 
        debug_assert!(!self.has_monomorph(&types), "monomorph already exists");
 
        self.monomorphs.push(types);
 
    }
 

	
 
    pub(crate) fn has_any_monomorph(&self) -> bool {
 
        !self.monomorphs.is_empty()
 
    }
 

	
 
    pub(crate) fn has_monomorph(&self, types: &Vec<ConcreteType>) -> bool {
 
        debug_assert_eq!(self.poly_vars.len(), types.len(), "mismatch in number of polymorphic types");
 
        for monomorph in &self.monomorphs {
 
            if monomorph == types { return true; }
 
        }
 

	
 
        return false;
 
    }
 
}
 

	
 
pub enum DefinedTypeVariant {
 
    Enum(EnumType),
 
    Union(UnionType),
 
    Struct(StructType),
 
    Function(FunctionType),
 
    Component(ComponentType)
 
}
 

	
 
pub struct PolyVar {
 
    identifier: Identifier,
 
    /// Whether the polymorphic variables is used directly in the definition of
 
    /// the type (not including bodies of function/component types)
 
    is_in_use: bool,
 
}
 

	
 
impl DefinedTypeVariant {
 
    pub(crate) fn type_class(&self) -> TypeClass {
 
        match self {
 
            DefinedTypeVariant::Enum(_) => TypeClass::Enum,
 
            DefinedTypeVariant::Union(_) => TypeClass::Union,
 
            DefinedTypeVariant::Struct(_) => TypeClass::Struct,
 
            DefinedTypeVariant::Function(_) => TypeClass::Function,
 
            DefinedTypeVariant::Component(_) => TypeClass::Component
 
        }
 
    }
 

	
 
    pub(crate) fn as_struct(&self) -> &StructType {
 
        match self {
 
            DefinedTypeVariant::Struct(v) => v,
 
            _ => unreachable!("Cannot convert {} to struct variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_enum(&self) -> &EnumType {
 
        match self {
 
            DefinedTypeVariant::Enum(v) => v,
 
            _ => unreachable!("Cannot convert {} to enum variant", self.type_class())
 
        }
 
    }
 

	
 
    pub(crate) fn as_union(&self) -> &UnionType {
 
        match self {
 
            DefinedTypeVariant::Union(v) => v,
 
            _ => unreachable!("Cannot convert {} to union variant", self.type_class())
 
        }
 
    }
 
}
 

	
 
struct PolymorphicVariable {
 
    identifier: Identifier,
 
    is_in_use: bool, // a polymorphic argument may be defined, but not used by the type definition
 
}
 

	
 
/// `EnumType` is the classical C/C++ enum type. It has various variants with
 
/// an assigned integer value. The integer values may be user-defined,
 
/// compiler-defined, or a mix of the two. If a user assigns the same enum
 
/// value multiple times, we assume the user is an expert and we consider both
 
/// variants to be equal to one another.
 
pub struct EnumType {
 
    pub(crate) variants: Vec<EnumVariant>,
 
    pub(crate) representation: PrimitiveType,
 
}
 

	
 
// TODO: Also support maximum u64 value
 
pub struct EnumVariant {
 
    pub(crate) identifier: Identifier,
 
    pub(crate) value: i64,
 
}
 

	
 
/// `UnionType` is the algebraic datatype (or sum type, or discriminated union).
 
/// A value is an element of the union, identified by its tag, and may contain
 
/// a single subtype.
 
pub struct UnionType {
 
    pub(crate) variants: Vec<UnionVariant>,
 
    pub(crate) tag_representation: PrimitiveType
 
}
 

	
 
pub struct UnionVariant {
 
    pub(crate) identifier: Identifier,
 
    pub(crate) embedded: Vec<ParserTypeId>, // zero-length does not have embedded values
 
    pub(crate) embedded: Vec<ParserType>, // zero-length does not have embedded values
 
    pub(crate) tag_value: i64,
 
}
 

	
 
pub struct StructType {
 
    pub(crate) fields: Vec<StructField>,
 
}
 

	
 
pub struct StructField {
 
    pub(crate) identifier: Identifier,
 
    pub(crate) parser_type: ParserTypeId,
 
    pub(crate) parser_type: ParserType,
 
}
 

	
 
pub struct FunctionType {
 
    pub return_type: ParserTypeId,
 
    pub return_types: Vec<ParserType>,
 
    pub arguments: Vec<FunctionArgument>
 
}
 

	
 
pub struct ComponentType {
 
    pub variant: ComponentVariant,
 
    pub arguments: Vec<FunctionArgument>
 
}
 

	
 
pub struct FunctionArgument {
 
    identifier: Identifier,
 
    parser_type: ParserTypeId,
 
    parser_type: ParserType,
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Type table
 
//------------------------------------------------------------------------------
 

	
 
// TODO: @cleanup Do I really need this, doesn't make the code that much cleaner
 
struct TypeIterator {
 
    breadcrumbs: Vec<(RootId, DefinitionId)>
 
}
 

	
 
impl TypeIterator {
 
    fn new() -> Self {
 
        Self{ breadcrumbs: Vec::with_capacity(32) }
 
    }
 

	
 
    fn reset(&mut self, root_id: RootId, definition_id: DefinitionId) {
 
        self.breadcrumbs.clear();
 
        self.breadcrumbs.push((root_id, definition_id))
 
    }
 

	
 
    fn push(&mut self, root_id: RootId, definition_id: DefinitionId) {
 
        self.breadcrumbs.push((root_id, definition_id));
 
    }
 

	
 
    fn contains(&self, root_id: RootId, definition_id: DefinitionId) -> bool {
 
        for (stored_root_id, stored_definition_id) in self.breadcrumbs.iter() {
 
            if *stored_root_id == root_id && *stored_definition_id == definition_id { return true; }
 
        }
 

	
 
        return false
 
    }
 

	
 
    fn top(&self) -> Option<(RootId, DefinitionId)> {
 
        self.breadcrumbs.last().map(|(r, d)| (*r, *d))
 
    }
 

	
 
    fn pop(&mut self) {
 
        debug_assert!(!self.breadcrumbs.is_empty());
 
        self.breadcrumbs.pop();
 
    }
 
}
 

	
 
/// Result from attempting to resolve a `ParserType` using the symbol table and
 
/// the type table.
 
enum ResolveResult {
 
    /// ParserType is a builtin type
 
    BuiltIn,
 
    /// ParserType points to a polymorphic argument, contains the index of the
 
    /// polymorphic argument in the outermost definition (e.g. we may have 
 
    /// structs nested three levels deep, but in the innermost struct we can 
 
    /// only use the polyargs that are specified in the type definition of the
 
    /// outermost struct).
 
    PolyArg(usize),
 
    Builtin,
 
    PolymoprhicArgument,
 
    /// ParserType points to a user-defined type that is already resolved in the
 
    /// type table.
 
    Resolved((RootId, DefinitionId)),
 
    Resolved(RootId, DefinitionId),
 
    /// ParserType points to a user-defined type that is not yet resolved into
 
    /// the type table.
 
    Unresolved((RootId, DefinitionId))
 
    Unresolved(RootId, DefinitionId)
 
}
 

	
 
pub(crate) struct TypeTable {
 
    /// Lookup from AST DefinitionId to a defined type. Considering possible
 
    /// polymorphs is done inside the `DefinedType` struct.
 
    lookup: HashMap<DefinitionId, DefinedType>,
 
    /// Iterator over `(module, definition)` tuples used as workspace to make sure
 
    /// that each base definition of all a type's subtypes are resolved.
 
    iter: TypeIterator,
 
    /// Iterator over `parser type`s during the process where `parser types` are
 
    /// resolved into a `(module, definition)` tuple.
 
    parser_type_iter: VecDeque<ParserTypeId>,
 
}
 

	
 
pub(crate) struct TypeCtx<'a> {
 
    symbols: &'a SymbolTable,
 
    heap: &'a mut Heap,
 
    modules: &'a [LexedModule]
 
    modules: &'a [Module]
 
}
 

	
 
impl<'a> TypeCtx<'a> {
 
    pub(crate) fn new(symbols: &'a SymbolTable, heap: &'a mut Heap, modules: &'a [LexedModule]) -> Self {
 
    pub(crate) fn new(symbols: &'a SymbolTable, heap: &'a mut Heap, modules: &'a [Module]) -> Self {
 
        Self{ symbols, heap, modules }
 
    }
 
}
 

	
 
impl TypeTable {
 
    /// Construct a new type table without any resolved types.
 
    pub(crate) fn new() -> Self {
 
        Self{ 
 
            lookup: HashMap::new(), 
 
            iter: TypeIterator::new(), 
 
            parser_type_iter: VecDeque::with_capacity(64), 
 
        }
 
    }
 

	
 
    pub(crate) fn build_base_types(&mut self, ctx: &mut TypeCtx) -> Result<(), ParseError> {
 
        // Make sure we're allowed to cast root_id to index into ctx.modules
 
        debug_assert!(self.lookup.is_empty());
 
        debug_assert!(self.iter.top().is_none());
 
        debug_assert!(self.parser_type_iter.is_empty());
 

	
 
        if cfg!(debug_assertions) {
 
            for (index, module) in ctx.modules.iter().enumerate() {
 
                debug_assert_eq!(index, module.root_id.index as usize);
 
            }
 
        }
 

	
 
        // Use context to guess hashmap size
 
        let reserve_size = ctx.heap.definitions.len();
 
        self.lookup.reserve(reserve_size);
 

	
 
        // TODO: @cleanup Rework this hack
 
        for root_idx in 0..ctx.modules.len() {
 
            let last_definition_idx = ctx.heap[ctx.modules[root_idx].root_id].definitions.len();
 
            for definition_idx in 0..last_definition_idx {
 
                let definition_id = ctx.heap[ctx.modules[root_idx].root_id].definitions[definition_idx];
 
                self.resolve_base_definition(ctx, definition_id)?;
 
            }
 
        }
 

	
 
        debug_assert_eq!(self.lookup.len(), reserve_size, "mismatch in reserved size of type table");
 

	
 
        Ok(())
 
    }
 

	
 
    /// Retrieves base definition from type table. We must be able to retrieve
 
    /// it as we resolve all base types upon type table construction (for now).
 
    /// However, in the future we might do on-demand type resolving, so return
 
    /// an option anyway
 
    pub(crate) fn get_base_definition(&self, definition_id: &DefinitionId) -> Option<&DefinedType> {
 
        self.lookup.get(&definition_id)
 
    }
 

	
 
    /// Instantiates a monomorph for a given base definition.
 
    pub(crate) fn add_monomorph(&mut self, definition_id: &DefinitionId, types: Vec<ConcreteType>) {
 
        debug_assert!(
 
            self.lookup.contains_key(definition_id),
 
            "attempting to instantiate monomorph of definition unknown to type table"
 
        );
 

	
 
        let definition = self.lookup.get_mut(definition_id).unwrap();
 
        definition.add_monomorph(types);
 
    }
 

	
 
    /// Checks if a given definition already has a specific monomorph
 
    pub(crate) fn has_monomorph(&mut self, definition_id: &DefinitionId, types: &Vec<ConcreteType>) -> bool {
 
        debug_assert!(
 
            self.lookup.contains_key(definition_id),
 
            "attempting to check monomorph existence of definition unknown to type table"
 
        );
 

	
 
        let definition = self.lookup.get(definition_id).unwrap();
 
        definition.has_monomorph(types)
 
    }
 

	
 
    /// This function will resolve just the basic definition of the type, it
 
    /// will not handle any of the monomorphized instances of the type.
 
    fn resolve_base_definition<'a>(&'a mut self, ctx: &mut TypeCtx, definition_id: DefinitionId) -> Result<(), ParseError> {
 
        // Check if we have already resolved the base definition
 
        if self.lookup.contains_key(&definition_id) { return Ok(()); }
 

	
 
        let root_id = Self::find_root_id(ctx, definition_id);
 
        self.iter.reset(root_id, definition_id);
 

	
 
        while let Some((root_id, definition_id)) = self.iter.top() {
 
            // We have a type to resolve
 
            let definition = &ctx.heap[definition_id];
 

	
 
            let can_pop_breadcrumb = match definition {
 
                // TODO: @cleanup Borrow rules hax
 
                Definition::Enum(_) => self.resolve_base_enum_definition(ctx, root_id, definition_id),
 
                Definition::Union(_) => self.resolve_base_union_definition(ctx, root_id, definition_id),
 
                Definition::Struct(_) => self.resolve_base_struct_definition(ctx, root_id, definition_id),
 
                Definition::Component(_) => self.resolve_base_component_definition(ctx, root_id, definition_id),
 
                Definition::Function(_) => self.resolve_base_function_definition(ctx, root_id, definition_id),
 
            }?;
 

	
 
            // Otherwise: `ingest_resolve_result` has pushed a new breadcrumb
 
            // that we must follow before we can resolve the current type
 
            if can_pop_breadcrumb {
 
                self.iter.pop();
 
            }
 
        }
 

	
 
        // We must have resolved the type
 
        debug_assert!(self.lookup.contains_key(&definition_id), "base type not resolved");
 
        Ok(())
 
    }
 

	
 
    /// Resolve the basic enum definition to an entry in the type table. It will
 
    /// not instantiate any monomorphized instances of polymorphic enum
 
    /// definitions. If a subtype has to be resolved first then this function
 
    /// will return `false` after calling `ingest_resolve_result`.
 
    fn resolve_base_enum_definition(&mut self, ctx: &mut TypeCtx, root_id: RootId, definition_id: DefinitionId) -> Result<bool, ParseError> {
 
        debug_assert!(ctx.heap[definition_id].is_enum());
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base enum already resolved");
 
        
 
        let definition = ctx.heap[definition_id].as_enum();
 

	
 
        let mut enum_value = -1;
 
        let mut min_enum_value = 0;
 
        let mut max_enum_value = 0;
 
        let mut variants = Vec::with_capacity(definition.variants.len());
 
        for variant in &definition.variants {
 
            enum_value += 1;
 
            match &variant.value {
 
                EnumVariantValue::None => {
 
                    variants.push(EnumVariant{
 
                        identifier: variant.identifier.clone(),
 
                        value: enum_value,
 
                    });
 
                },
 
                EnumVariantValue::Integer(override_value) => {
 
                    enum_value = *override_value;
 
                    variants.push(EnumVariant{
 
                        identifier: variant.identifier.clone(),
 
                        value: enum_value,
 
                    });
 
                }
 
            }
 
            if enum_value < min_enum_value { min_enum_value = enum_value; }
 
            else if enum_value > max_enum_value { max_enum_value = enum_value; }
 
        }
 

	
 
        // Ensure enum names and polymorphic args do not conflict
 
        self.check_identifier_collision(
 
            ctx, root_id, &variants, |variant| &variant.identifier, "enum variant"
 
        )?;
 

	
 
        // Because we're parsing an enum, the programmer cannot put the
 
        // polymorphic variables inside the variants. But the polymorphic
 
        // variables might still be present as "marker types"
 
        self.check_poly_args_collision(ctx, root_id, &definition.poly_vars)?;
 
        let poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 

	
 
        // Note: although we cannot have embedded type dependent on the
 
        // polymorphic variables, they might still be present as tokens
 
        let definition_id = definition.this.upcast();
 
        self.lookup.insert(definition_id, DefinedType {
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Enum(EnumType{
 
                variants,
 
                representation: Self::enum_tag_type(min_enum_value, max_enum_value)
 
            }),
 
            poly_vars: self.create_initial_poly_vars(&definition.poly_vars),
 
            poly_vars,
 
            is_polymorph: false,
 
            is_pointerlike: false,
 
            monomorphs: Vec::new()
 
        });
 

	
 
        Ok(true)
 
    }
 

	
 
    /// Resolves the basic union definiton to an entry in the type table. It
 
    /// will not instantiate any monomorphized instances of polymorphic union
 
    /// definitions. If a subtype has to be resolved first then this function
 
    /// will return `false` after calling `ingest_resolve_result`.
 
    fn resolve_base_union_definition(&mut self, ctx: &mut TypeCtx, root_id: RootId, definition_id: DefinitionId) -> Result<bool, ParseError> {
 
        debug_assert!(ctx.heap[definition_id].is_union());
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base union already resolved");
 

	
 
        let definition = ctx.heap[definition_id].as_union();
 

	
 
        // Make sure all embedded types are resolved
 
        for variant in &definition.variants {
 
            match &variant.value {
 
                UnionVariantValue::None => {},
 
                UnionVariantValue::Embedded(embedded) => {
 
                    for embedded_id in embedded {
 
                        let resolve_result = self.resolve_base_parser_type(ctx, &definition.poly_vars, root_id, *embedded_id)?;
 
                    for parser_type in embedded {
 
                        let resolve_result = self.resolve_base_parser_type(ctx, root_id, parser_type)?;
 
                        if !self.ingest_resolve_result(ctx, resolve_result)? {
 
                            return Ok(false)
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        // If here then all embedded types are resolved
 

	
 
        // Determine the union variants
 
        let mut tag_value = -1;
 
        let mut variants = Vec::with_capacity(definition.variants.len());
 
        for variant in &definition.variants {
 
            tag_value += 1;
 
            let embedded = match &variant.value {
 
                UnionVariantValue::None => { Vec::new() },
 
                UnionVariantValue::Embedded(embedded) => {
 
                    // Type should be resolvable, we checked this above
 
                    embedded.clone()
 
                },
 
            };
 

	
 
            variants.push(UnionVariant{
 
                identifier: variant.identifier.clone(),
 
                embedded,
 
                tag_value,
 
            })
 
        }
 

	
 
        // Ensure union names and polymorphic args do not conflict
 
        self.check_identifier_collision(
 
            ctx, root_id, &variants, |variant| &variant.identifier, "union variant"
 
        )?;
 
        self.check_poly_args_collision(ctx, root_id, &definition.poly_vars)?;
 

	
 
        let mut poly_args = self.create_initial_poly_vars(&definition.poly_vars);
 
        // Construct polymorphic variables and mark the ones that are in use
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for variant in &variants {
 
            for embedded_id in &variant.embedded {
 
                self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, definition_id, &mut poly_args, root_id, *embedded_id)?;
 
            for parser_type in &variant.embedded {
 
                Self::mark_used_polymorphic_variables(&mut poly_vars, parser_type);
 
            }
 
        }
 
        let is_polymorph = poly_args.iter().any(|arg| arg.is_in_use);
 

	
 
        // Insert base definition in type table
 
        self.lookup.insert(definition_id, DefinedType {
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Union(UnionType{
 
                variants,
 
                tag_representation: Self::enum_tag_type(-1, tag_value),
 
            }),
 
            poly_vars: poly_args,
 
            is_polymorph,
 
            is_pointerlike: false, // TODO: @cyclic_types
 
            monomorphs: Vec::new()
 
        });
 

	
 
        Ok(true)
 
    }
 

	
 
    /// Resolves the basic struct definition to an entry in the type table. It
 
    /// will not instantiate any monomorphized instances of polymorphic struct
 
    /// definitions.
 
    fn resolve_base_struct_definition(&mut self, ctx: &mut TypeCtx, root_id: RootId, definition_id: DefinitionId) -> Result<bool, ParseError> {
 
        debug_assert!(ctx.heap[definition_id].is_struct());
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base struct already resolved");
 

	
 
        let definition = ctx.heap[definition_id].as_struct();
 

	
 
        // Make sure all fields point to resolvable types
 
        for field_definition in &definition.fields {
 
            let resolve_result = self.resolve_base_parser_type(ctx, &definition.poly_vars, root_id, field_definition.parser_type)?;
 
            let resolve_result = self.resolve_base_parser_type(ctx, root_id, &field_definition.parser_type)?;
 
            if !self.ingest_resolve_result(ctx, resolve_result)? {
 
                return Ok(false)
 
            }
 
        }
 

	
 
        // All fields types are resolved, construct base type
 
        let mut fields = Vec::with_capacity(definition.fields.len());
 
        for field_definition in &definition.fields {
 
            fields.push(StructField{
 
                identifier: field_definition.field.clone(),
 
                parser_type: field_definition.parser_type,
 
                parser_type: field_definition.parser_type.clone(),
 
            })
 
        }
 

	
 
        // And make sure no conflicts exist in field names and/or polymorphic args
 
        self.check_identifier_collision(
 
            ctx, root_id, &fields, |field| &field.identifier, "struct field"
 
        )?;
 
        self.check_poly_args_collision(ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct representation of polymorphic arguments
 
        let mut poly_args = self.create_initial_poly_vars(&definition.poly_vars);
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for field in &fields {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, definition_id, &mut poly_args, root_id, field.parser_type)?;
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &field.parser_type);
 
        }
 

	
 
        let is_polymorph = poly_args.iter().any(|arg| arg.is_in_use);
 

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Struct(StructType{
 
                fields,
 
            }),
 
            poly_vars: poly_args,
 
            is_polymorph,
 
            is_pointerlike: false, // TODO: @cyclic
 
            monomorphs: Vec::new(),
 
        });
 

	
 
        Ok(true)
 
    }
 

	
 
    /// Resolves the basic function definition to an entry in the type table. It
 
    /// will not instantiate any monomorphized instances of polymorphic function
 
    /// definitions.
 
    fn resolve_base_function_definition(&mut self, ctx: &mut TypeCtx, root_id: RootId, definition_id: DefinitionId) -> Result<bool, ParseError> {
 
        debug_assert!(ctx.heap[definition_id].is_function());
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base function already resolved");
 

	
 
        let definition = ctx.heap[definition_id].as_function();
 
        let return_type = definition.return_type;
 

	
 
        // Check the return type
 
        let resolve_result = self.resolve_base_parser_type(
 
            ctx, &definition.poly_vars, root_id, definition.return_type
 
        )?;
 
        debug_assert_eq!(definition.return_types.len(), 1, "not one return type"); // TODO: @ReturnValues
 
        let resolve_result = self.resolve_base_parser_type(ctx, root_id, &definition.return_types[0])?;
 
        if !self.ingest_resolve_result(ctx, resolve_result)? {
 
            return Ok(false)
 
        }
 

	
 
        // Check the argument types
 
        for param_id in &definition.parameters {
 
            let param = &ctx.heap[*param_id];
 
            let resolve_result = self.resolve_base_parser_type(
 
                ctx, &definition.poly_vars, root_id, param.parser_type
 
            )?;
 
            let resolve_result = self.resolve_base_parser_type(ctx, root_id, &param.parser_type)?;
 
            if !self.ingest_resolve_result(ctx, resolve_result)? {
 
                return Ok(false)
 
            }
 
        }
 

	
 
        // Construct arguments to function
 
        let mut arguments = Vec::with_capacity(definition.parameters.len());
 
        for param_id in &definition.parameters {
 
            let param = &ctx.heap[*param_id];
 
            arguments.push(FunctionArgument{
 
                identifier: param.identifier.clone(),
 
                parser_type: param.parser_type,
 
                parser_type: param.parser_type.clone(),
 
            })
 
        }
 

	
 
        // Check conflict of argument and polyarg identifiers
 
        self.check_identifier_collision(
 
            ctx, root_id, &arguments, |arg| &arg.identifier, "function argument"
 
        )?;
 
        self.check_poly_args_collision(ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct polymorphic arguments
 
        let mut poly_args = self.create_initial_poly_vars(&definition.poly_vars);
 
        let return_type_id = definition.return_type;
 
        self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, definition_id, &mut poly_args, root_id, return_type_id)?;
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        Self::mark_used_polymorphic_variables(&mut poly_vars, &definition.return_types[0]);
 
        for argument in &arguments {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, definition_id, &mut poly_args, root_id, argument.parser_type)?;
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &argument.parser_type);
 
        }
 

	
 
        let is_polymorph = poly_args.iter().any(|arg| arg.is_in_use);
 

	
 
        // Construct entry in type table
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Function(FunctionType{
 
                return_type,
 
                return_types: definition.return_types.clone(),
 
                arguments,
 
            }),
 
            poly_vars: poly_args,
 
            is_polymorph,
 
            is_pointerlike: false, // TODO: @cyclic
 
            monomorphs: Vec::new(),
 
        });
 

	
 
        Ok(true)
 
    }
 

	
 
    /// Resolves the basic component definition to an entry in the type table.
 
    /// It will not instantiate any monomorphized instancees of polymorphic
 
    /// component definitions.
 
    fn resolve_base_component_definition(&mut self, ctx: &mut TypeCtx, root_id: RootId, definition_id: DefinitionId) -> Result<bool, ParseError> {
 
        debug_assert!(ctx.heap[definition_id].is_component());
 
        debug_assert!(!self.lookup.contains_key(&definition_id), "base component already resolved");
 

	
 
        let definition = ctx.heap[definition_id].as_component();
 
        let component_variant = definition.variant;
 

	
 
        // Check argument types
 
        for param_id in &definition.parameters {
 
            let param = &ctx.heap[*param_id];
 
            let resolve_result = self.resolve_base_parser_type(
 
                ctx, &definition.poly_vars, root_id, param.parser_type
 
            )?;
 
            let resolve_result = self.resolve_base_parser_type(ctx, root_id, &param.parser_type)?;
 
            if !self.ingest_resolve_result(ctx, resolve_result)? {
 
                return Ok(false)
 
            }
 
        }
 

	
 
        // Construct argument types
 
        let mut arguments = Vec::with_capacity(definition.parameters.len());
 
        for param_id in &definition.parameters {
 
            let param = &ctx.heap[*param_id];
 
            arguments.push(FunctionArgument{
 
                identifier: param.identifier.clone(),
 
                parser_type: param.parser_type
 
                parser_type: param.parser_type.clone()
 
            })
 
        }
 

	
 
        // Check conflict of argument and polyarg identifiers
 
        self.check_identifier_collision(
 
            ctx, root_id, &arguments, |arg| &arg.identifier, "component argument"
 
        )?;
 
        self.check_poly_args_collision(ctx, root_id, &definition.poly_vars)?;
 

	
 
        // Construct polymorphic arguments
 
        let mut poly_args = self.create_initial_poly_vars(&definition.poly_vars);
 
        let mut poly_vars = Self::create_polymorphic_variables(&definition.poly_vars);
 
        for argument in &arguments {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, definition_id, &mut poly_args, root_id, argument.parser_type)?;
 
            Self::mark_used_polymorphic_variables(&mut poly_vars, &argument.parser_type)?;
 
        }
 

	
 
        let is_polymorph = poly_args.iter().any(|v| v.is_in_use);
 
        let is_polymorph = poly_vars.iter().any(|v| v.is_in_use);
 

	
 
        // Construct entry in type table
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_root: root_id,
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Component(ComponentType{
 
                variant: component_variant,
 
                arguments,
 
            }),
 
            poly_vars: poly_args,
 
            poly_vars,
 
            is_polymorph,
 
            is_pointerlike: false, // TODO: @cyclic
 
            monomorphs: Vec::new(),
 
        });
 

	
 
        Ok(true)
 
    }
 

	
 
    /// Takes a ResolveResult and returns `true` if the caller can happily
 
    /// continue resolving its current type, or `false` if the caller must break
 
    /// resolving the current type and exit to the outer resolving loop. In the
 
    /// latter case the `result` value was `ResolveResult::Unresolved`, implying
 
    /// that the type must be resolved first.
 
    fn ingest_resolve_result(&mut self, ctx: &TypeCtx, result: ResolveResult) -> Result<bool, ParseError> {
 
        match result {
 
            ResolveResult::BuiltIn | ResolveResult::PolyArg(_) => Ok(true),
 
            ResolveResult::Resolved(_) => Ok(true),
 
            ResolveResult::Unresolved((root_id, definition_id)) => {
 
            ResolveResult::Builtin | ResolveResult::PolymoprhicArgument => Ok(true),
 
            ResolveResult::Resolved(_, _) => Ok(true),
 
            ResolveResult::Unresolved(root_id, definition_id) => {
 
                if self.iter.contains(root_id, definition_id) {
 
                    // Cyclic dependency encountered
 
                    // TODO: Allow this
 
                    let mut error = ParseError::new_error(
 
                        &ctx.modules[root_id.index as usize].source, ctx.heap[definition_id].position(),
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 
                    let mut error = ParseError::new_error_str_at_span(
 
                        module_source, ctx.heap[definition_id].identifier().span,
 
                        "Evaluating this type definition results in a cyclic type"
 
                    );
 

	
 
                    for (breadcrumb_idx, (root_id, definition_id)) in self.iter.breadcrumbs.iter().enumerate() {
 
                        let msg = if breadcrumb_idx == 0 {
 
                            "The cycle started with this definition"
 
                        } else {
 
                            "Which depends on this definition"
 
                        };
 

	
 
                        error = error.with_postfixed_info(
 
                            &ctx.modules[root_id.index as usize].source,
 
                            ctx.heap[*definition_id].position(), msg
 
                        );
 
                        let module_source = &ctx.modules[root_id.index as usize].source;
 
                        error = error.with_info_str_at_span(module_source, ctx.heap[*definition_id].identifier().span, msg);
 
                    }
 

	
 
                    Err(error)
 
                } else {
 
                    // Type is not yet resolved, so push IDs on iterator and
 
                    // continue the resolving loop
 
                    self.iter.push(root_id, definition_id);
 
                    Ok(false)
 
                }
 
            }
 
        }
 
    }
 

	
 
    /// Each type definition may consist of several embedded subtypes. This
 
    /// function checks whether that embedded type is a builtin, a direct
 
    /// reference to a polymorphic argument, or an (un)resolved type definition.
 
    /// If the embedded type's symbol cannot be found then this function returns
 
    /// an error.
 
    /// Each type may consist of embedded types. If this type does not have a
 
    /// fixed implementation (e.g. an input port may have an embedded type
 
    /// indicating the type of messages, but it always exists in the runtime as
 
    /// a port identifier, so it has a fixed implementation) then this function
 
    /// will traverse the embedded types to ensure all of them are resolved.
 
    ///
 
    /// If the embedded type is resolved, then one always receives the type's
 
    /// (module, definition) tuple. If any of the types in the embedded type's
 
    /// tree is not yet resolved, then one may receive a (module, definition)
 
    /// tuple that does not correspond to the `parser_type_id` passed into this
 
    /// function.
 
    fn resolve_base_parser_type(&mut self, ctx: &TypeCtx, poly_vars: &Vec<Identifier>, root_id: RootId, parser_type_id: ParserTypeId) -> Result<ResolveResult, ParseError> {
 
    /// Hence if one checks a particular parser type for being resolved, one may
 
    /// get back a result value indicating an embedded type (with a different
 
    /// DefinitionId) is unresolved.
 
    fn resolve_base_parser_type(&mut self, ctx: &TypeCtx, root_id: RootId, parser_type: &ParserType) -> Result<ResolveResult, ParseError> {
 
        // Note that as we iterate over the elements of a
 
        use ParserTypeVariant as PTV;
 

	
 
        // Prepping iterator
 
        self.parser_type_iter.clear();
 
        self.parser_type_iter.push_back(parser_type_id);
 

	
 
        // Result for the very first time we resolve a
 
        // Result for the very first time we resolve a type (i.e the outer type
 
        // that we're actually looking up)
 
        let mut resolve_result = None;
 
        let mut set_resolve_result = |v: ResolveResult| {
 
            if resolve_result.is_none() { resolve_result = Some(v); }
 
        };
 

	
 
        'resolve_loop: while let Some(parser_type_id) = self.parser_type_iter.pop_back() {
 
            let parser_type = &ctx.heap[parser_type_id];
 

	
 
            match &parser_type.variant {
 
                // Builtin types. An array is a builtin as it is implemented as a
 
                // couple of pointers, so we do not require the subtype to be fully
 
                // resolved. Similar for input/output ports.
 
                PTV::Array(_) | PTV::Input(_) | PTV::Output(_) | PTV::Message |
 
                PTV::Bool | PTV::Byte | PTV::Short | PTV::Int | PTV::Long |
 
                PTV::String => {
 
                    set_resolve_result(ResolveResult::BuiltIn);
 
        for element in parser_type.elements.iter() {
 
            match element.variant {
 
                PTV::Message | PTV::Bool |
 
                PTV::UInt8 | PTV::UInt16 | PTV::UInt32 | PTV::UInt64 |
 
                PTV::SInt8 | PTV::SInt16 | PTV::SInt32 | PTV::SInt64 |
 
                PTV::Character | PTV::String |
 
                PTV::Array | PTV::Input | PTV::Output => {
 
                    // Nothing to do: these are builtin types or types with a
 
                    // fixed implementation
 
                    set_resolve_result(ResolveResult::Builtin);
 
                },
 
                // IntegerLiteral types and the inferred marker are not allowed in
 
                // definitions of types
 
                PTV::IntegerLiteral |
 
                PTV::Inferred => {
 
                    debug_assert!(false, "Encountered illegal ParserTypeVariant within type definition");
 
                    unreachable!();
 
                PTV::IntegerLiteral | PTV::Inferred => {
 
                    // As we're parsing the type definitions where these kinds
 
                    // of types are impossible/disallowed to express:
 
                    unreachable!("illegal ParserTypeVariant within type definition");
 
                },
 
                // Symbolic type, make sure its base type, and the base types
 
                // of all members of the embedded type tree are resolved. We
 
                // don't care about monomorphs yet.
 
                PTV::Symbolic(symbolic) => {
 
                    // Check if the symbolic type is one of the definition's
 
                    // polymorphic arguments. If so then we can halt the
 
                    // execution
 
                    for (poly_arg_idx, poly_arg) in poly_vars.iter().enumerate() {
 
                        if symbolic.identifier.matches_identifier(poly_arg) {
 
                            set_resolve_result(ResolveResult::PolyArg(poly_arg_idx));
 
                            continue 'resolve_loop;
 
                        }
 
                    }
 

	
 
                    // Lookup the definition in the symbol table
 
                    let (symbol, mut ident_iter) = ctx.symbols.resolve_namespaced_identifier(root_id, &symbolic.identifier);
 
                    if symbol.is_none() {
 
                        return Err(ParseError::new_error(
 
                            &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                            "Could not resolve type"
 
                        ))
 
                    }
 

	
 
                    let symbol_value = symbol.unwrap();
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 

	
 
                    match symbol_value.symbol {
 
                        Symbol::Namespace(_) => {
 
                            // Reference to a namespace instead of a type
 
                            let last_ident = ident_iter.prev();
 
                            return if ident_iter.num_remaining() == 0 {
 
                                // Could also have polymorphic args, but we 
 
                                // don't care, just throw this error: 
 
                                Err(ParseError::new_error(
 
                                    module_source, symbolic.identifier.position,
 
                                    "Expected a type, got a module name"
 
                                ))
 
                            } else if last_ident.is_some() && last_ident.map(|(_, poly_args)| poly_args.is_some()).unwrap() {
 
                                // Halted at a namespaced because we encountered
 
                                // polymorphic arguments
 
                                Err(ParseError::new_error(
 
                                    module_source, symbolic.identifier.position,
 
                                    "Illegal specification of polymorphic arguments to a module name"
 
                                ))
 
                            } else {
 
                                // Impossible (with the current implementation 
 
                                // of the symbol table)
 
                                unreachable!(
 
                                    "Got namespace symbol with {} returned symbols from {}",
 
                                    ident_iter.num_returned(),
 
                                    &String::from_utf8_lossy(&symbolic.identifier.value)
 
                                );
 
                            }
 
                PTV::PolymorphicArgument(_, _) => {
 
                    set_resolve_result(ResolveResult::PolymoprhicArgument);
 
                },
 
                        Symbol::Definition((root_id, definition_id)) => {
 
                            let definition = &ctx.heap[definition_id];
 
                            if ident_iter.num_remaining() > 0 {
 
                                // Namespaced identifier is longer than the type
 
                                // we found. Return the appropriate message
 
                                return if definition.is_struct() || definition.is_enum() {
 
                                    Err(ParseError::new_error(
 
                                        module_source, symbolic.identifier.position,
 
                                        &format!(
 
                                            "Unknown type '{}', did you mean to use '{}'?",
 
                                            String::from_utf8_lossy(&symbolic.identifier.value),
 
                                            String::from_utf8_lossy(&definition.identifier().value)
 
                                        )
 
                                    ))
 
                                } else {
 
                                    Err(ParseError::new_error(
 
                                        module_source, symbolic.identifier.position,
 
                                        "Unknown datatype"
 
                                    ))
 
                                }
 
                            }
 

	
 
                            // Found a match, make sure it is a datatype
 
                PTV::Definition(embedded_id, _) => {
 
                    let definition = &ctx.heap[embedded_id];
 
                    if !(definition.is_struct() || definition.is_enum() || definition.is_union()) {
 
                                return Err(ParseError::new_error(
 
                                    module_source, symbolic.identifier.position,
 
                                    "Embedded types must be datatypes (structs or enums)"
 
                        let module_source = &ctx.modules[root_id.index as usize].source;
 
                        return Err(ParseError::new_error_str_at_span(
 
                            module_source, element.full_span, "expected a datatype (struct, enum or union)"
 
                        ))
 
                    }
 

	
 
                            // Found a struct/enum definition
 
                            if !self.lookup.contains_key(&definition_id) {
 
                                // Type is not yet resoled, immediately return
 
                                // this
 
                                return Ok(ResolveResult::Unresolved((root_id, definition_id)));
 
                            }
 

	
 
                            // Type is resolved, so set as result, but continue
 
                            // iterating over the parser types in the embedded
 
                            // type's tree
 
                            set_resolve_result(ResolveResult::Resolved((root_id, definition_id)));
 

	
 
                            // Note: because we're resolving parser types, not
 
                            // embedded types, we're parsing a tree, so we can't
 
                            // get stuck in a cyclic loop.
 
                            let last_ident = ident_iter.prev();
 
                            if let Some((_, Some(poly_args))) = last_ident {
 
                                for poly_arg_type_id in poly_args {
 
                                    self.parser_type_iter.push_back(*poly_arg_type_id);
 
                                }
 
                            }
 
                        }
 
                    if self.lookup.contains_key(&embedded_id) {
 
                        set_resolve_result(ResolveResult::Resolved(definition.defined_in(), embedded_id))
 
                    } else {
 
                        return Ok(ResolveResult::Unresolved(definition.defined_in(), embedded_id))
 
                    }
 
                }
 
            }
 
        }
 

	
 
        // If here then all types in the embedded type's tree were resolved.
 
        debug_assert!(resolve_result.is_some(), "faulty logic in ParserType resolver");
 
        return Ok(resolve_result.unwrap())
 
    }
 

	
 
    fn create_initial_poly_vars(&self, poly_args: &[Identifier]) -> Vec<PolyVar> {
 
        poly_args
 
            .iter()
 
            .map(|v| PolyVar{ identifier: v.clone(), is_in_use: false })
 
            .collect()
 
    }
 

	
 
    /// This function modifies the passed `poly_args` by checking the embedded
 
    /// type tree. This should be called after `resolve_base_parser_type` is
 
    /// called on each node in this tree: we assume that each symbolic type was
 
    /// resolved to either a polymorphic arg or a definition.
 
    ///
 
    /// This function will also make sure that if the embedded type has
 
    /// polymorphic variables itself, that the number of polymorphic variables
 
    /// matches the number of arguments in the associated definition.
 
    ///
 
    /// Finally, for all embedded types (which includes function/component 
 
    /// arguments and return types) in type definitions we will modify the AST
 
    /// when the embedded type is a polymorphic variable or points to another
 
    /// user-defined type.
 
    fn check_and_resolve_embedded_type_and_modify_poly_args(
 
        &mut self, ctx: &mut TypeCtx, 
 
        type_definition_id: DefinitionId, poly_args: &mut [PolyVar], 
 
        root_id: RootId, embedded_type_id: ParserTypeId,
 
    ) -> Result<(), ParseError> {
 
        use ParserTypeVariant as PTV;
 

	
 
        self.parser_type_iter.clear();
 
        self.parser_type_iter.push_back(embedded_type_id);
 

	
 
        'type_loop: while let Some(embedded_type_id) = self.parser_type_iter.pop_back() {
 
            let embedded_type = &mut ctx.heap[embedded_type_id];
 

	
 
            match &mut embedded_type.variant {
 
                PTV::Message | PTV::Bool | 
 
                PTV::Byte | PTV::Short | PTV::Int | PTV::Long |
 
                PTV::String => {
 
                    // Builtins, no modification/iteration required
 
                },
 
                PTV::IntegerLiteral | PTV::Inferred => {
 
                    // TODO: @hack Allowed for now so we can continue testing 
 
                    //  the parser/lexer
 
                    // debug_assert!(false, "encountered illegal parser type during ParserType/PolyArg modification");
 
                    // unreachable!();
 
                },
 
                PTV::Array(subtype_id) |
 
                PTV::Input(subtype_id) |
 
                PTV::Output(subtype_id) => {
 
                    // Outer type is fixed, but inner type might be symbolic
 
                    self.parser_type_iter.push_back(*subtype_id);
 
                },
 
                PTV::Symbolic(symbolic) => {
 
                    for (poly_arg_idx, poly_arg) in poly_args.iter_mut().enumerate() {
 
                        if symbolic.identifier.matches_identifier(&poly_arg.identifier) {
 
                            poly_arg.is_in_use = true;
 
                            // TODO: If we allow higher-kinded types in the future,
 
                            //  then we can't continue here, but must resolve the
 
                            //  polyargs as well
 
                            debug_assert!(symbolic.identifier.get_poly_args().is_none(), "got polymorphic arguments to a polymorphic variable");
 
                            debug_assert!(symbolic.variant.is_none(), "symbolic parser type's variant already resolved");
 
                            symbolic.variant = Some(SymbolicParserTypeVariant::PolyArg(type_definition_id, poly_arg_idx));
 
                            continue 'type_loop;
 
                        }
 
                    }
 

	
 
                    // Must match a definition
 
                    let (symbol, ident_iter) = ctx.symbols.resolve_namespaced_identifier(root_id, &symbolic.identifier);
 
                    debug_assert!(symbol.is_some(), "could not resolve symbolic parser type when determining poly args");
 
                    let symbol = symbol.unwrap();
 
                    debug_assert_eq!(ident_iter.num_remaining(), 0, "no exact symbol match when determining poly args");
 
                    let (_root_id, definition_id) = symbol.as_definition().unwrap();
 
    
 
                    // Must be a struct, enum, or union, we checked this
 
                    let defined_type = self.lookup.get(&definition_id).unwrap();
 
                    let (_, poly_args) = ident_iter.prev().unwrap();
 
                    let poly_args = poly_args.unwrap_or_default();
 

	
 
                    if cfg!(debug_assertions) {
 
                        // Everything here should already be checked in 
 
                        // `resolve_base_parser_type`.
 
                        let type_class = defined_type.definition.type_class();
 
                        debug_assert!(
 
                            type_class == TypeClass::Struct || type_class == TypeClass::Enum || type_class == TypeClass::Union,
 
                            "embedded type's class is not struct, enum or union"
 
                        );
 
                        debug_assert_eq!(poly_args.len(), symbolic.identifier.poly_args.len());
 
                    }
 
    
 
                    if poly_args.len() != defined_type.poly_vars.len() {
 
                        // Mismatch in number of polymorphic arguments. This is 
 
                        // not allowed in type definitions (no inference is 
 
                        // allowed within type definitions, only in bodies of
 
                        // functions/components).
 
                        let module_source = &ctx.modules[root_id.index as usize].source;
 
                        let number_args_msg = if defined_type.poly_vars.is_empty() {
 
                            String::from("is not polymorphic")
 
                        } else {
 
                            format!("accepts {} polymorphic arguments", defined_type.poly_vars.len())
 
                        };
 
    
 
                        return Err(ParseError::new_error(
 
                            module_source, symbolic.identifier.position,
 
                            &format!(
 
                                "The type '{}' {}, but {} polymorphic arguments were provided",
 
                                String::from_utf8_lossy(&symbolic.identifier.strip_poly_args()),
 
                                number_args_msg, poly_args.len()
 
                            )
 
                        ));
 
                    }
 
    
 
                    self.parser_type_iter.extend(poly_args);
 
                    debug_assert!(symbolic.variant.is_none(), "symbolic parser type's variant already resolved");
 
                    symbolic.variant = Some(SymbolicParserTypeVariant::Definition(definition_id));
 
                }
 
            }
 
        }
 

	
 
        // All nodes in the embedded type tree were valid
 
        Ok(())
 
    }
 

	
 
    /// Go through a list of identifiers and ensure that all identifiers have
 
    /// unique names
 
    fn check_identifier_collision<T: Sized, F: Fn(&T) -> &Identifier>(
 
        &self, ctx: &TypeCtx, root_id: RootId, items: &[T], getter: F, item_name: &'static str
 
    ) -> Result<(), ParseError> {
 
        for (item_idx, item) in items.iter().enumerate() {
 
            let item_ident = getter(item);
 
            for other_item in &items[0..item_idx] {
 
                let other_item_ident = getter(other_item);
 
                if item_ident == other_item_ident {
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 
                    return Err(ParseError::new_error(
 
                        module_source, item_ident.position, &format!("This {} is defined more than once", item_name)
 
                    ).with_postfixed_info(
 
                        module_source, other_item_ident.position, &format!("The other {} is defined here", item_name)
 
                    return Err(ParseError::new_error_at_span(
 
                        module_source, item_ident.span, format!("This {} is defined more than once", item_name)
 
                    ).with_info_at_span(
 
                        module_source, other_item_ident.span, format!("The other {} is defined here", item_name)
 
                    ));
 
                }
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    /// Go through a list of polymorphic arguments and make sure that the
 
    /// arguments all have unique names, and the arguments do not conflict with
 
    /// any symbols defined at the module scope.
 
    fn check_poly_args_collision(
 
        &self, ctx: &TypeCtx, root_id: RootId, poly_args: &[Identifier]
 
    ) -> Result<(), ParseError> {
 
        // Make sure polymorphic arguments are unique and none of the
 
        // identifiers conflict with any imported scopes
 
        for (arg_idx, poly_arg) in poly_args.iter().enumerate() {
 
            for other_poly_arg in &poly_args[..arg_idx] {
 
                if poly_arg == other_poly_arg {
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 
                    return Err(ParseError::new_error(
 
                        module_source, poly_arg.position,
 
                    return Err(ParseError::new_error_str_at_span(
 
                        module_source, poly_arg.span,
 
                        "This polymorphic argument is defined more than once"
 
                    ).with_postfixed_info(
 
                        module_source, other_poly_arg.position,
 
                        module_source, other_poly_arg.span,
 
                        "It conflicts with this polymorphic argument"
 
                    ));
 
                }
 
            }
 

	
 
            // Check if identifier conflicts with a symbol defined or imported
 
            // in the current module
 
            if let Some(symbol) = ctx.symbols.resolve_symbol(root_id, &poly_arg.value) {
 
            if let Some(symbol) = ctx.symbols.get_symbol_by_name(SymbolScope::Module(root_id), poly_arg.value.as_bytes()) {
 
                // We have a conflict
 
                let module_source = &ctx.modules[root_id.index as usize].source;
 
                return Err(ParseError::new_error(
 
                    module_source, poly_arg.position,
 
                let introduction_span = symbol.variant.span_of_introduction(ctx.heap);
 
                return Err(ParseError::new_error_str_at_span(
 
                    module_source, poly_arg.span,
 
                    "This polymorphic argument conflicts with another symbol"
 
                ).with_postfixed_info(
 
                    module_source, symbol.position,
 
                ).with_info_str_at_span(
 
                    module_source, introduction_span,
 
                    "It conflicts due to this symbol"
 
                ));
 
            }
 
        }
 

	
 
        // All arguments are fine
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Small utilities
 
    //--------------------------------------------------------------------------
 

	
 
    fn create_polymorphic_variables(variables: &[Identifier]) -> Vec<PolymorphicVariable> {
 
        let mut result = Vec::with_capacity(variables.len());
 
        for variable in variables.iter() {
 
            result.push(PolymorphicVariable{ identifier: variable.clone(), is_in_use: false });
 
        }
 

	
 
        result
 
    }
 

	
 
    fn mark_used_polymorphic_variables(poly_vars: &mut Vec<PolymorphicVariable>, parser_type: &ParserType) {
 
        for element in & parser_type.elements {
 
            if let ParserTypeVariant::PolymorphicArgument(_, idx) = element {
 
                poly_vars[*idx].is_in_use = true;
 
            }
 
        }
 
    }
 

	
 
    fn enum_tag_type(min_tag_value: i64, max_tag_value: i64) -> PrimitiveType {
 
        // TODO: @consistency tag values should be handled correctly
 
        debug_assert!(min_tag_value <= max_tag_value);
 
        let abs_max_value = min_tag_value.abs().max(max_tag_value.abs());
 
        if abs_max_value <= u8::max_value() as i64 {
 
            PrimitiveType::Byte
 
        } else if abs_max_value <= u16::max_value() as i64 {
 
            PrimitiveType::Short
 
        } else if abs_max_value <= u32::max_value() as i64 {
 
            PrimitiveType::Int
 
        } else {
 
            PrimitiveType::Long
 
        }
 
    }
 

	
 
    fn find_root_id(ctx: &TypeCtx, definition_id: DefinitionId) -> RootId {
 
        // TODO: Keep in lookup or something
 
        for module in ctx.modules {
 
            let root_id = module.root_id;
 
            let root = &ctx.heap[root_id];
 
            for module_definition_id in root.definitions.iter() {
 
                if *module_definition_id == definition_id {
 
                    return root_id
 
                }
 
            }
 
        }
 

	
 
        debug_assert!(false, "DefinitionId without corresponding RootId");
 
        unreachable!();
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/visitor_linker.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::{
 
    symbol_table::*, 
 
    type_table::*,
 
    utils::*,
 
};
 

	
 
use super::visitor::{
 
    STMT_BUFFER_INIT_CAPACITY,
 
    EXPR_BUFFER_INIT_CAPACITY,
 
    TYPE_BUFFER_INIT_CAPACITY,
 
    Ctx, 
 
    Visitor2, 
 
    VisitorResult
 
};
 

	
 
#[derive(PartialEq, Eq)]
 
enum DefinitionType {
 
    None,
 
    Primitive(ComponentId),
 
    Composite(ComponentId),
 
    Function(FunctionId)
 
    Primitive(ComponentDefinitionId),
 
    Composite(ComponentDefinitionId),
 
    Function(FunctionDefinitionId)
 
}
 

	
 
impl DefinitionType {
 
    fn is_primitive(&self) -> bool { if let Self::Primitive(_) = self { true } else { false } }
 
    fn is_composite(&self) -> bool { if let Self::Composite(_) = self { true } else { false } }
 
    fn is_function(&self) -> bool { if let Self::Function(_) = self { true } else { false } }
 
}
 

	
 
/// This particular visitor will go through the entire AST in a recursive manner
 
/// and check if all statements and expressions are legal (e.g. no "return"
 
/// statements in component definitions), and will link certain AST nodes to
 
/// their appropriate targets (e.g. goto statements, or function calls).
 
///
 
/// This visitor will not perform control-flow analysis (e.g. making sure that
 
/// each function actually returns) and will also not perform type checking. So
 
/// the linking of function calls and component instantiations will be checked
 
/// and linked to the appropriate definitions, but the return types and/or
 
/// arguments will not be checked for validity.
 
///
 
/// The visitor visits each statement in a block in a breadth-first manner
 
/// first. We are thereby sure that we have found all variables/labels in a
 
/// particular block. In this phase nodes may queue statements for insertion
 
/// (e.g. the insertion of an `EndIf` statement for a particular `If`
 
/// statement). These will be inserted after visiting every node, after which
 
/// the visitor recurses into each statement in a block.
 
///
 
/// Because of this scheme expressions will not be visited in the breadth-first
 
/// pass.
 
pub(crate) struct ValidityAndLinkerVisitor {
 
    /// `in_sync` is `Some(id)` if the visitor is visiting the children of a
 
    /// synchronous statement. A single value is sufficient as nested
 
    /// synchronous statements are not allowed
 
    in_sync: Option<SynchronousStatementId>,
 
    /// `in_while` contains the last encountered `While` statement. This is used
 
    /// to resolve unlabeled `Continue`/`Break` statements.
 
    in_while: Option<WhileStatementId>,
 
    // Traversal state: current scope (which can be used to find the parent
 
    // scope), the definition variant we are considering, and whether the
 
    // visitor is performing breadthwise block statement traversal.
 
    cur_scope: Option<Scope>,
 
    def_type: DefinitionType,
 
    performing_breadth_pass: bool,
 
    // Parent expression (the previous stmt/expression we visited that could be
 
    // used as an expression parent)
 
    expr_parent: ExpressionParent,
 
    // Keeping track of relative position in block in the breadth-first pass.
 
    // May not correspond to block.statement[index] if any statements are
 
    // inserted after the breadth-pass
 
    relative_pos_in_block: u32,
 
    // Single buffer of statement IDs that we want to traverse in a block.
 
    // Required to work around Rust borrowing rules and to prevent constant
 
    // cloning of vectors.
 
    statement_buffer: Vec<StatementId>,
 
    // Another buffer, now with expression IDs, to prevent constant cloning of
 
    // vectors while working around rust's borrowing rules
 
    expression_buffer: Vec<ExpressionId>,
 
    // Yet another buffer, now with parser type IDs, similar to above
 
    parser_type_buffer: Vec<ParserTypeId>,
 
    // Statements to insert after the breadth pass in a single block
 
    insert_buffer: Vec<(u32, StatementId)>,
 
}
 

	
 
impl ValidityAndLinkerVisitor {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            in_sync: None,
 
            in_while: None,
 
            cur_scope: None,
 
            expr_parent: ExpressionParent::None,
 
            def_type: DefinitionType::None,
 
            performing_breadth_pass: false,
 
            relative_pos_in_block: 0,
 
            statement_buffer: Vec::with_capacity(STMT_BUFFER_INIT_CAPACITY),
 
            expression_buffer: Vec::with_capacity(EXPR_BUFFER_INIT_CAPACITY),
 
            parser_type_buffer: Vec::with_capacity(TYPE_BUFFER_INIT_CAPACITY),
 
            insert_buffer: Vec::with_capacity(32),
 
        }
 
    }
 

	
 
    fn reset_state(&mut self) {
 
        self.in_sync = None;
 
        self.in_while = None;
 
        self.cur_scope = None;
 
        self.expr_parent = ExpressionParent::None;
 
        self.def_type = DefinitionType::None;
 
        self.relative_pos_in_block = 0;
 
        self.performing_breadth_pass = false;
 
        self.statement_buffer.clear();
 
        self.expression_buffer.clear();
 
        self.parser_type_buffer.clear();
 
        self.insert_buffer.clear();
 
    }
 

	
 
    /// Debug call to ensure that we didn't make any mistakes in any of the
 
    /// employed buffers
 
    fn check_post_definition_state(&self) {
 
        debug_assert!(self.statement_buffer.is_empty());
 
        debug_assert!(self.expression_buffer.is_empty());
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
        debug_assert!(self.insert_buffer.is_empty());
 
    }
 
}
 

	
 
impl Visitor2 for ValidityAndLinkerVisitor {
 
    //--------------------------------------------------------------------------
 
    // Definition visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_component_definition(&mut self, ctx: &mut Ctx, id: ComponentId) -> VisitorResult {
 
    fn visit_component_definition(&mut self, ctx: &mut Ctx, id: ComponentDefinitionId) -> VisitorResult {
 
        self.reset_state();
 

	
 
        self.def_type = match &ctx.heap[id].variant {
 
            ComponentVariant::Primitive => DefinitionType::Primitive(id),
 
            ComponentVariant::Composite => DefinitionType::Composite(id),
 
        };
 
        self.cur_scope = Some(Scope::Definition(id.upcast()));
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        // Visit types of parameters
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
        let comp_def = &ctx.heap[id];
 
        self.parser_type_buffer.extend(
 
            comp_def.parameters
 
                .iter()
 
                .map(|id| ctx.heap[*id].parser_type)
 
        );
 

	
 
        let num_types = self.parser_type_buffer.len();
 
        for idx in 0..num_types {
 
            self.visit_parser_type(ctx, self.parser_type_buffer[idx])?;
 
        }
 

	
 
        self.parser_type_buffer.clear();
 

	
 
        // Visit statements in component body
 
        let body_id = ctx.heap[id].body;
 
        self.performing_breadth_pass = true;
 
        self.visit_stmt(ctx, body_id)?;
 
        self.visit_block_stmt(ctx, body_id)?;
 
        self.performing_breadth_pass = false;
 
        self.visit_stmt(ctx, body_id)?;
 
        self.visit_block_stmt(ctx, body_id)?;
 

	
 
        self.check_post_definition_state();
 
        Ok(())
 
    }
 

	
 
    fn visit_function_definition(&mut self, ctx: &mut Ctx, id: FunctionId) -> VisitorResult {
 
    fn visit_function_definition(&mut self, ctx: &mut Ctx, id: FunctionDefinitionId) -> VisitorResult {
 
        self.reset_state();
 

	
 
        // Set internal statement indices
 
        self.def_type = DefinitionType::Function(id);
 
        self.cur_scope = Some(Scope::Definition(id.upcast()));
 
        self.expr_parent = ExpressionParent::None;
 

	
 
        // Visit types of parameters
 
        debug_assert!(self.parser_type_buffer.is_empty());
 
        let func_def = &ctx.heap[id];
 
        self.parser_type_buffer.extend(
 
            func_def.parameters
 
                .iter()
 
                .map(|id| ctx.heap[*id].parser_type)
 
        );
 
        self.parser_type_buffer.push(func_def.return_type);
 

	
 
        let num_types = self.parser_type_buffer.len();
 
        for idx in 0..num_types {
 
            self.visit_parser_type(ctx, self.parser_type_buffer[idx])?;
 
        }
 

	
 
        self.parser_type_buffer.clear();
 

	
 
        // Visit statements in function body
 
        let body_id = ctx.heap[id].body;
 
        self.performing_breadth_pass = true;
 
        self.visit_stmt(ctx, body_id)?;
 
        self.visit_block_stmt(ctx, body_id)?;
 
        self.performing_breadth_pass = false;
 
        self.visit_stmt(ctx, body_id)?;
 
        self.visit_block_stmt(ctx, body_id)?;
 

	
 
        self.check_post_definition_state();
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Statement visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_block_stmt(&mut self, ctx: &mut Ctx, id: BlockStatementId) -> VisitorResult {
 
        self.visit_block_stmt_with_hint(ctx, id, None)
 
    }
 

	
 
    fn visit_local_memory_stmt(&mut self, ctx: &mut Ctx, id: MemoryStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let variable_id = ctx.heap[id].variable;
 
            self.checked_local_add(ctx, self.relative_pos_in_block, variable_id)?;
 
        } else {
 
            let variable_id = ctx.heap[id].variable;
 
            let parser_type_id = ctx.heap[variable_id].parser_type;
 
            self.visit_parser_type(ctx, parser_type_id)?;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_local_channel_stmt(&mut self, ctx: &mut Ctx, id: ChannelStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let (from_id, to_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.from, stmt.to)
 
            };
 
            self.checked_local_add(ctx, self.relative_pos_in_block, from_id)?;
 
            self.checked_local_add(ctx, self.relative_pos_in_block, to_id)?;
 
        } else {
 
            let chan_stmt = &ctx.heap[id];
 
            let from_type_id = ctx.heap[chan_stmt.from].parser_type;
 
            let to_type_id = ctx.heap[chan_stmt.to].parser_type;
 
            self.visit_parser_type(ctx, from_type_id)?;
 
            self.visit_parser_type(ctx, to_type_id)?;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_labeled_stmt(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Add label to block lookup
 
            self.checked_label_add(ctx, id)?;
 

	
 
            // Modify labeled statement itself
 
            let labeled = &mut ctx.heap[id];
 
            labeled.relative_pos_in_block = self.relative_pos_in_block;
 
            labeled.in_sync = self.in_sync.clone();
 
        }
 

	
 
        let body_id = ctx.heap[id].body;
 
        self.visit_stmt(ctx, body_id)?;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_if_stmt(&mut self, ctx: &mut Ctx, id: IfStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let position = ctx.heap[id].position;
 
            let end_if_id = ctx.heap.alloc_end_if_statement(|this| {
 
                EndIfStatement {
 
                    this,
 
                    start_if: id,
 
                    position,
 
                    next: None,
 
                }
 
            });
 
            let stmt = &mut ctx.heap[id];
 
            stmt.end_if = Some(end_if_id);
 
            self.insert_buffer.push((self.relative_pos_in_block + 1, end_if_id.upcast()));
 
        } else {
 
        if !self.performing_breadth_pass {
 
            // Traverse expression and bodies
 
            let (test_id, true_id, false_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.test, stmt.true_body, stmt.false_body)
 
            };
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::If(id);
 
            self.visit_expr(ctx, test_id)?;
 
            self.expr_parent = ExpressionParent::None;
 

	
 
            self.visit_stmt(ctx, true_id)?;
 
            self.visit_stmt(ctx, false_id)?;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_while_stmt(&mut self, ctx: &mut Ctx, id: WhileStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let position = ctx.heap[id].position;
 
            let end_while_id = ctx.heap.alloc_end_while_statement(|this| {
 
                EndWhileStatement {
 
                    this,
 
                    start_while: id,
 
                    position,
 
                    next: None,
 
                }
 
            });
 
            let stmt = &mut ctx.heap[id];
 
            stmt.end_while = Some(end_while_id);
 
            stmt.in_sync = self.in_sync.clone();
 

	
 
            self.insert_buffer.push((self.relative_pos_in_block + 1, end_while_id.upcast()));
 
        } else {
 
            let (test_id, body_id) = {
 
                let stmt = &ctx.heap[id];
 
                (stmt.test, stmt.body)
 
            };
 
            let old_while = self.in_while.replace(id);
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::While(id);
 
            self.visit_expr(ctx, test_id)?;
 
            self.expr_parent = ExpressionParent::None;
 

	
 
            self.visit_stmt(ctx, body_id)?;
 
            self.in_while = old_while;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_break_stmt(&mut self, ctx: &mut Ctx, id: BreakStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Should be able to resolve break statements with a label in the
 
            // breadth pass, no need to do after resolving all labels
 
            let target_end_while = {
 
                let stmt = &ctx.heap[id];
 
                let target_while_id = self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?;
 
                let target_while = &ctx.heap[target_while_id];
 
                debug_assert!(target_while.end_while.is_some());
 
                target_while.end_while.unwrap()
 
            };
 

	
 
            let stmt = &mut ctx.heap[id];
 
            stmt.target = Some(target_end_while);
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_continue_stmt(&mut self, ctx: &mut Ctx, id: ContinueStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let target_while_id = {
 
                let stmt = &ctx.heap[id];
 
                self.resolve_break_or_continue_target(ctx, stmt.position, &stmt.label)?
 
            };
 

	
 
            let stmt = &mut ctx.heap[id];
 
            stmt.target = Some(target_while_id)
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_synchronous_stmt(&mut self, ctx: &mut Ctx, id: SynchronousStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Check for validity of synchronous statement
 
            let cur_sync_position = ctx.heap[id].position;
 
            if self.in_sync.is_some() {
 
                // Nested synchronous statement
 
                let old_sync = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, cur_sync_position, "Illegal nested synchronous statement")
 
                        .with_postfixed_info(&ctx.module.source, old_sync.position, "It is nested in this synchronous statement")
 
                );
 
            }
 

	
 
            if !self.def_type.is_primitive() {
 
                return Err(ParseError::new_error(
 
                    &ctx.module.source, cur_sync_position,
 
                    "Synchronous statements may only be used in primitive components"
 
                ));
 
            }
 

	
 
            // Append SynchronousEnd pseudo-statement
 
            let sync_end_id = ctx.heap.alloc_end_synchronous_statement(|this| EndSynchronousStatement{
 
                this,
 
                position: cur_sync_position,
 
                start_sync: id,
 
                next: None,
 
            });
 
            let sync_start = &mut ctx.heap[id];
 
            sync_start.end_sync = Some(sync_end_id);
 
            self.insert_buffer.push((self.relative_pos_in_block + 1, sync_end_id.upcast()));
 
        } else {
 
            let sync_body = ctx.heap[id].body;
 
            let old = self.in_sync.replace(id);
 
            self.visit_stmt_with_hint(ctx, sync_body, Some(id))?;
 
            self.in_sync = old;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_return_stmt(&mut self, ctx: &mut Ctx, id: ReturnStatementId) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            let stmt = &ctx.heap[id];
 
            if !self.def_type.is_function() {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Return statements may only appear in function bodies")
 
                );
 
            }
 
        } else {
 
            // If here then we are within a function
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::Return(id);
 
            self.visit_expr(ctx, ctx.heap[id].expression)?;
 
            self.expr_parent = ExpressionParent::None;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_assert_stmt(&mut self, ctx: &mut Ctx, id: AssertStatementId) -> VisitorResult {
 
        let stmt = &ctx.heap[id];
 
        if self.performing_breadth_pass {
 
            if self.def_type.is_function() {
 
                // TODO: We probably want to allow this. Mark the function as
 
                //  using asserts, and then only allow calls to these functions
 
                //  within components. Such a marker will cascade through any
 
                //  functions that then call an asserting function
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Illegal assert statement in a function")
 
                );
 
            }
 

	
 
            // We are in a component of some sort, but we also need to be within a
 
            // synchronous statement
 
            if self.in_sync.is_none() {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, stmt.position, "Illegal assert statement outside of a synchronous block")
 
                );
 
            }
 
        } else {
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            let expr_id = stmt.expression;
 

	
 
            self.expr_parent = ExpressionParent::Assert(id);
 
            self.visit_expr(ctx, expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_goto_stmt(&mut self, ctx: &mut Ctx, id: GotoStatementId) -> VisitorResult {
 
        if !self.performing_breadth_pass {
 
            // Must perform goto label resolving after the breadth pass, this
 
            // way we are able to find all the labels in current and outer
 
            // scopes.
 
            let target_id = self.find_label(ctx, &ctx.heap[id].label)?;
 
            ctx.heap[id].target = Some(target_id);
 

	
 
            let target = &ctx.heap[target_id];
 
            if self.in_sync != target.in_sync {
 
                // We can only goto the current scope or outer scopes. Because
 
                // nested sync statements are not allowed so if the value does
 
                // not match, then we must be inside a sync scope
 
                debug_assert!(self.in_sync.is_some());
 
                let goto_stmt = &ctx.heap[id];
 
                let sync_stmt = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, goto_stmt.position, "Goto may not escape the surrounding synchronous block")
 
                        .with_postfixed_info(&ctx.module.source, target.position, "This is the target of the goto statement")
 
                        .with_postfixed_info(&ctx.module.source, sync_stmt.position, "Which will jump past this statement")
 
                );
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_new_stmt(&mut self, ctx: &mut Ctx, id: NewStatementId) -> VisitorResult {
 
        // Link the call expression following the new statement
 
        if self.performing_breadth_pass {
 
            // TODO: Cleanup error messages, can be done cleaner
 
            // Make sure new statement occurs within a composite component
 
            let call_expr_id = ctx.heap[id].expression;
 
            if !self.def_type.is_composite() {
 
                let new_stmt = &ctx.heap[id];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, new_stmt.position, "Instantiating components may only be done in composite components")
 
                );
 
            }
 

	
 
            // We make sure that we point to a symbolic method. Checking that it
 
            // points to a component is done in the depth pass.
 
            let call_expr = &ctx.heap[call_expr_id];
 
            if let Method::Symbolic(_) = &call_expr.method {
 
                // We're fine
 
            } else {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, call_expr.position, "Must instantiate a component")
 
                );
 
            }
 
        } else {
 
            // Just call `visit_call_expr`. We do some extra work we don't have
 
            // to, but this prevents silly mistakes.
 
            let call_expr_id = ctx.heap[id].expression;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::New(id);
 
            self.visit_call_expr(ctx, call_expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_expr_stmt(&mut self, ctx: &mut Ctx, id: ExpressionStatementId) -> VisitorResult {
 
        if !self.performing_breadth_pass {
 
            let expr_id = ctx.heap[id].expression;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::ExpressionStmt(id);
 
            self.visit_expr(ctx, expr_id)?;
 
            self.expr_parent = ExpressionParent::None;
 
        }
 

	
 
        Ok(())
 
    }
 

	
 

	
 
    //--------------------------------------------------------------------------
 
    // Expression visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_assignment_expr(&mut self, ctx: &mut Ctx, id: AssignmentExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let upcast_id = id.upcast();
 
        let assignment_expr = &mut ctx.heap[id];
 

	
 
        let left_expr_id = assignment_expr.left;
 
        let right_expr_id = assignment_expr.right;
 
        let old_expr_parent = self.expr_parent;
 
        assignment_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, left_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, right_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 
        Ok(())
 
    }
 

	
 
    fn visit_conditional_expr(&mut self, ctx: &mut Ctx, id: ConditionalExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let conditional_expr = &mut ctx.heap[id];
 

	
 
        let test_expr_id = conditional_expr.test;
 
        let true_expr_id = conditional_expr.true_expression;
 
        let false_expr_id = conditional_expr.false_expression;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        conditional_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, test_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, true_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 2);
 
        self.visit_expr(ctx, false_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_binary_expr(&mut self, ctx: &mut Ctx, id: BinaryExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let binary_expr = &mut ctx.heap[id];
 
        let left_expr_id = binary_expr.left;
 
        let right_expr_id = binary_expr.right;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        binary_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, left_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, right_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_unary_expr(&mut self, ctx: &mut Ctx, id: UnaryExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let unary_expr = &mut ctx.heap[id];
 
        let expr_id = unary_expr.expression;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        unary_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(id.upcast(), 0);
 
        self.visit_expr(ctx, expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_indexing_expr(&mut self, ctx: &mut Ctx, id: IndexingExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let indexing_expr = &mut ctx.heap[id];
 

	
 
        let subject_expr_id = indexing_expr.subject;
 
        let index_expr_id = indexing_expr.index;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        indexing_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, subject_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, index_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_slicing_expr(&mut self, ctx: &mut Ctx, id: SlicingExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 
        let upcast_id = id.upcast();
 
        let slicing_expr = &mut ctx.heap[id];
 

	
 
        let subject_expr_id = slicing_expr.subject;
 
        let from_expr_id = slicing_expr.from_index;
 
        let to_expr_id = slicing_expr.to_index;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        slicing_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 0);
 
        self.visit_expr(ctx, subject_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 1);
 
        self.visit_expr(ctx, from_expr_id)?;
 
        self.expr_parent = ExpressionParent::Expression(upcast_id, 2);
 
        self.visit_expr(ctx, to_expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_select_expr(&mut self, ctx: &mut Ctx, id: SelectExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let select_expr = &mut ctx.heap[id];
 
        let expr_id = select_expr.subject;
 

	
 
        let old_expr_parent = self.expr_parent;
 
        select_expr.parent = old_expr_parent;
 

	
 
        self.expr_parent = ExpressionParent::Expression(id.upcast(), 0);
 
        self.visit_expr(ctx, expr_id)?;
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_array_expr(&mut self, ctx: &mut Ctx, id: ArrayExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let upcast_id = id.upcast();
 
        let array_expr = &mut ctx.heap[id];
 

	
 
        let old_num_exprs = self.expression_buffer.len();
 
        self.expression_buffer.extend(&array_expr.elements);
 
        let new_num_exprs = self.expression_buffer.len();
 

	
 
        let old_expr_parent = self.expr_parent;
 
        array_expr.parent = old_expr_parent;
 

	
 
        for field_expr_idx in old_num_exprs..new_num_exprs {
 
            let field_expr_id = self.expression_buffer[field_expr_idx];
 
            self.expr_parent = ExpressionParent::Expression(upcast_id, field_expr_idx as u32);
 
            self.visit_expr(ctx, field_expr_id)?;
 
        }
 

	
 
        self.expression_buffer.truncate(old_num_exprs);
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_literal_expr(&mut self, ctx: &mut Ctx, id: LiteralExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        const FIELD_NOT_FOUND_SENTINEL: usize = usize::max_value();
 

	
 
        let constant_expr = &mut ctx.heap[id];
 
        let old_expr_parent = self.expr_parent;
 
        constant_expr.parent = old_expr_parent;
 

	
 
        match &mut constant_expr.value {
 
            Literal::Null | Literal::True | Literal::False |
 
            Literal::Character(_) | Literal::Integer(_) => {
 
                // Just the parent has to be set, done above
 
            },
 
            Literal::Struct(literal) => {
 
                let upcast_id = id.upcast();
 

	
 
                // Retrieve and set the literal's definition
 
                let definition = self.find_symbol_of_type(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &literal.identifier, TypeClass::Struct
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 

	
 
                let definition = definition.definition.as_struct();
 

	
 
                // Make sure all fields are specified, none are specified twice
 
                // and all fields exist on the struct definition
 
                let mut specified = Vec::new(); // TODO: @performance
 
                specified.resize(definition.fields.len(), false);
 

	
 
                for field in &mut literal.fields {
 
                    // Find field in the struct definition
 
                    field.field_idx = FIELD_NOT_FOUND_SENTINEL;
 
                    for (def_field_idx, def_field) in definition.fields.iter().enumerate() {
 
                        if field.identifier == def_field.identifier {
 
                            field.field_idx = def_field_idx;
 
                            break;
 
                        }
 
                    }
 

	
 
                    // Check if not found
 
                    if field.field_idx == FIELD_NOT_FOUND_SENTINEL {
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, field.identifier.position,
 
                            &format!(
 
                                "This field does not exist on the struct '{}'",
 
                                &String::from_utf8_lossy(&literal.identifier.value),
 
                            )
 
                        ));
 
                    }
 

	
 
                    // Check if specified more than once
 
                    if specified[field.field_idx] {
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, field.identifier.position,
 
                            "This field is specified more than once"
 
                        ));
 
                    }
 

	
 
                    specified[field.field_idx] = true;
 
                }
 

	
 
                if !specified.iter().all(|v| *v) {
 
                    // Some fields were not specified
 
                    let mut not_specified = String::new();
 
                    let mut num_not_specified = 0;
 
                    for (def_field_idx, is_specified) in specified.iter().enumerate() {
 
                        if !is_specified {
 
                            if !not_specified.is_empty() { not_specified.push_str(", ") }
 
                            let field_ident = &definition.fields[def_field_idx].identifier;
 
                            not_specified.push_str(&String::from_utf8_lossy(&field_ident.value));
 
                            num_not_specified += 1;
 
                        }
 
                    }
 

	
 
                    debug_assert!(num_not_specified > 0);
 
                    let msg = if num_not_specified == 1 {
 
                        format!("Not all fields are specified, '{}' is missing", not_specified)
 
                    } else {
 
                        format!("Not all fields are specified, [{}] are missing", not_specified)
 
                    };
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, literal.identifier.position, &msg
 
                    ));
 
                }
 

	
 
                // Need to traverse fields expressions in struct and evaluate
 
                // the poly args
 
                let old_num_exprs = self.expression_buffer.len();
 
                self.expression_buffer.extend(literal.fields.iter().map(|v| v.value));
 
                let new_num_exprs = self.expression_buffer.len();
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 

	
 
                for expr_idx in old_num_exprs..new_num_exprs {
 
                    let expr_id = self.expression_buffer[expr_idx];
 
                    self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
 
                    self.visit_expr(ctx, expr_id)?;
 
                }
 

	
 
                self.expression_buffer.truncate(old_num_exprs);
 
            },
 
            Literal::Enum(literal) => {
 
                // TODO: @tokenizer, remove this horrible hack once we have a 
 
                //  tokenizer and can distinguish types during AST-construction.
 
                //  For now see this horrible hack and weep!
 
                let (symbol, _) = ctx.symbols.resolve_namespaced_identifier(
 
                    ctx.module.root_id, &literal.identifier
 
                );
 
                if let Some(symbol) = symbol {
 
                    if let Symbol::Definition((_, definition_id)) = &symbol.symbol {
 
                        if let Some(defined_type) = ctx.types.get_base_definition(definition_id) {
 
                            if defined_type.definition.type_class() == TypeClass::Union {
 
                                // Transmute into union literal and call this function again
 
                                let old_identifier = literal.identifier.clone();
 
                                let lit_expr = &ctx.heap[id];
 
                                let old_position = lit_expr.position;
 

	
 
                                ctx.heap[id] = LiteralExpression{
 
                                    this: id,
 
                                    position: old_position,
 
                                    value: Literal::Union(LiteralUnion{
 
                                        identifier: old_identifier,
 
                                        values: vec!(),
 
                                        poly_args2: Vec::new(),
 
                                        definition: None,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    concrete_type: ConcreteType::default()
 
                                };
 

	
 
                                return self.visit_literal_expr(ctx, id);
 
                            }
 
                        }
 
                    }
 
                }
 

	
 
                // Retrieve and set definion of enumeration
 
                let (definition, ident_iter) = self.find_symbol_of_type_variant(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types, 
 
                    &literal.identifier, TypeClass::Enum
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 

	
 
                // Make sure the variant exists
 
                let (variant_ident, _) = ident_iter.prev().unwrap();
 
                let enum_definition = definition.definition.as_enum();
 

	
 
                match enum_definition.variants.iter().position(|variant| {
 
                    variant.identifier.value == variant_ident
 
                }) {
 
                    Some(variant_idx) => {
 
                        literal.variant_idx = variant_idx;
 
                    },
 
                    None => {
 
                        // Reborrow
 
                        let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                        let literal = ctx.heap[id].value.as_enum();
 
                        let enum_definition = ctx.heap[definition.ast_definition].as_enum();
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, literal.identifier.position,
 
                            &format!(
 
                                "The variant '{}' does not exist on the enum '{}'",
 
                                &variant, &String::from_utf8_lossy(&enum_definition.identifier.value)
 
                            )
 
                        ));
 
                    }
 
                }
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 
            },
 
            Literal::Union(literal) => {
 
                let upcast_id = id.upcast();
 

	
 
                // Retrieve and set definition of union
 
                let (definition, ident_iter) = self.find_symbol_of_type_variant(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &literal.identifier, TypeClass::Union
 
                )?;
 
                literal.definition = Some(definition.ast_definition);
 
                
 
                // Make sure the variant exists
 
                let (variant_ident, _) = ident_iter.prev().unwrap();
 
                let union_definition = definition.definition.as_union();
 

	
 
                match union_definition.variants.iter().position(|variant| {
 
                    variant.identifier.value == variant_ident
 
                }) {
 
                    Some(variant_idx) => {
 
                        literal.variant_idx = variant_idx;
 
                    },
 
                    None => {
 
                        // Reborrow
 
                        let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                        let literal = ctx.heap[id].value.as_union();
 
                        let union_definition = ctx.heap[definition.ast_definition].as_union();
 
                        return Err(ParseError::new_error(
 
                            &ctx.module.source, literal.identifier.position,
 
                            &format!(
 
                                "The variant '{}' does not exist on the union '{}'",
 
                                &variant, &String::from_utf8_lossy(&union_definition.identifier.value)
 
                            )
 
                        ));
 
                    }
 
                }
 

	
 
                // Make sure the number of specified values matches the expected
 
                // number of embedded values in the union variant.
 
                let union_variant = &union_definition.variants[literal.variant_idx];
 
                if union_variant.embedded.len() != literal.values.len() {
 
                    // Reborrow
 
                    let variant = String::from_utf8_lossy(variant_ident).to_string();
 
                    let literal = ctx.heap[id].value.as_union();
 
                    let union_definition = ctx.heap[definition.ast_definition].as_union();
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, literal.identifier.position,
 
                        &format!(
 
                            "The variant '{}' of union '{}' expects {} embedded values, but {} were specified",
 
                            variant, &String::from_utf8_lossy(&union_definition.identifier.value),
 
                            union_variant.embedded.len(), literal.values.len()
 
                        ),
 
                    ))
 
                }
 

	
 
                // Traverse embedded values of union (if any) and evaluate the
 
                // polymorphic arguments
 
                let old_num_exprs = self.expression_buffer.len();
 
                self.expression_buffer.extend(&literal.values);
 
                let new_num_exprs = self.expression_buffer.len();
 

	
 
                self.visit_literal_poly_args(ctx, id)?;
 

	
 
                for expr_idx in old_num_exprs..new_num_exprs {
 
                    let expr_id = self.expression_buffer[expr_idx];
 
                    self.expr_parent = ExpressionParent::Expression(upcast_id, expr_idx as u32);
 
                    self.visit_expr(ctx, expr_id)?;
 
                }
 

	
 
                self.expression_buffer.truncate(old_num_exprs);
 
            }
 
        }
 

	
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_call_expr(&mut self, ctx: &mut Ctx, id: CallExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let call_expr = &mut ctx.heap[id];
 
        let num_expr_args = call_expr.arguments.len();
 

	
 
        // Resolve the method to the appropriate definition and check the
 
        // legality of the particular method call.
 
        // TODO: @cleanup Unify in some kind of signature call, see similar
 
        //  cleanup comments with this `match` format.
 
        let num_definition_args;
 
        match &mut call_expr.method {
 
            Method::Create => {
 
                num_definition_args = 1;
 
            },
 
            Method::Fires => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'fires' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'fires' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 1;
 
            },
 
            Method::Get => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'get' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'get' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 1;
 
            },
 
            Method::Put => {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'put' may only occur in primitive component definitions"
 
                    ));
 
                }
 
                if self.in_sync.is_none() {
 
                    return Err(ParseError::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'put' may only occur inside synchronous blocks"
 
                    ));
 
                }
 
                num_definition_args = 2;
 
            }
 
            Method::Symbolic(symbolic) => {
 
                // Find symbolic procedure
 
                let expected_type = if let ExpressionParent::New(_) = self.expr_parent {
 
                    // Expect to find a component
 
                    TypeClass::Component
 
                } else {
 
                    // Expect to find a function
 
                    // TODO: @tokenizer, remove this ambiguity when tokenizer is implemented. Hacked
 
                    //  in here for now.
 
                    let (symbol, _) = ctx.symbols.resolve_namespaced_identifier(
 
                        ctx.module.root_id, &symbolic.identifier
 
                    );
 
                    if let Some(symbol) = symbol {
 
                        if let Symbol::Definition((_, definition_id)) = symbol.symbol {
 
                            if let Some(defined_type) = ctx.types.get_base_definition(&definition_id) {
 
                                if defined_type.definition.type_class() == TypeClass::Union {
 
                                    // Transmute into union literal and call the appropriate traverser
 
                                    let call_expr = &ctx.heap[id];
 
                                    let old_position = call_expr.position.clone();
 
                                    let old_arguments = call_expr.arguments.clone();
 
                                    let old_identifier = match &call_expr.method {
 
                                        Method::Symbolic(v) => v.identifier.clone(),
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    let expr_id = id.upcast();
 
                                    let lit_id = LiteralExpressionId(expr_id);
 
                                    ctx.heap[expr_id] = Expression::Literal(LiteralExpression{
 
                                        this: lit_id,
 
                                        position: old_position,
 
                                        value: Literal::Union(LiteralUnion{
 
                                            identifier: old_identifier,
 
                                            values: old_arguments,
 
                                            poly_args2: Vec::new(),
 
                                            definition: None,
 
                                            variant_idx: 0,
 
                                        }),
 
                                        parent: ExpressionParent::None,
 
                                        concrete_type: ConcreteType::default(),
 
                                    });
 
                                    
 
                                    return self.visit_literal_expr(ctx, lit_id);
 
                                }
 
                            }
 
                        }
 
                    }
 
                    TypeClass::Function
 
                };
 

	
 
                let definition = self.find_symbol_of_type(
 
                    &ctx.module.source, ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &symbolic.identifier, expected_type
 
                )?;
 

	
 
                symbolic.definition = Some(definition.ast_definition);
 
                match &definition.definition {
 
                    DefinedTypeVariant::Function(definition) => {
 
                        num_definition_args = definition.arguments.len();
 
                    },
 
                    DefinedTypeVariant::Component(definition) => {
 
                        num_definition_args = definition.arguments.len();
 
                    }
 
                    _ => unreachable!(),
 
                }
 
            }
 
        }
 

	
 
        // Check the poly args and the number of variables in the call
 
        // expression
 
        self.visit_call_poly_args(ctx, id)?;
 
        let call_expr = &mut ctx.heap[id];
 
        if num_expr_args != num_definition_args {
 
            return Err(ParseError::new_error(
 
                &ctx.module.source, call_expr.position,
 
                &format!(
 
                    "This call expects {} arguments, but {} were provided",
 
                    num_definition_args, num_expr_args
 
                )
 
            ));
 
        }
 

	
 
        // Recurse into all of the arguments and set the expression's parent
 
        let upcast_id = id.upcast();
 

	
 
        let old_num_exprs = self.expression_buffer.len();
 
        self.expression_buffer.extend(&call_expr.arguments);
 
        let new_num_exprs = self.expression_buffer.len();
 

	
 
        let old_expr_parent = self.expr_parent;
 
        call_expr.parent = old_expr_parent;
 

	
 
        for arg_expr_idx in old_num_exprs..new_num_exprs {
 
            let arg_expr_id = self.expression_buffer[arg_expr_idx];
 
            self.expr_parent = ExpressionParent::Expression(upcast_id, arg_expr_idx as u32);
 
            self.visit_expr(ctx, arg_expr_id)?;
 
        }
 

	
 
        self.expression_buffer.truncate(old_num_exprs);
 
        self.expr_parent = old_expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_variable_expr(&mut self, ctx: &mut Ctx, id: VariableExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let var_expr = &ctx.heap[id];
 
        let variable_id = self.find_variable(ctx, self.relative_pos_in_block, &var_expr.identifier)?;
 
        let var_expr = &mut ctx.heap[id];
 
        var_expr.declaration = Some(variable_id);
 
        var_expr.parent = self.expr_parent;
 

	
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // ParserType visitors
 
    //--------------------------------------------------------------------------
 

	
 
    fn visit_parser_type(&mut self, ctx: &mut Ctx, id: ParserTypeId) -> VisitorResult {
 
        let old_num_types = self.parser_type_buffer.len();
 
        match self.visit_parser_type_without_buffer_cleanup(ctx, id) {
 
            Ok(_) => {
 
                debug_assert_eq!(self.parser_type_buffer.len(), old_num_types);
 
                Ok(())
 
            },
 
            Err(err) => {
 
                self.parser_type_buffer.truncate(old_num_types);
 
                Err(err)
 
            }
 
        }
 
    }
 
}
 

	
 
impl ValidityAndLinkerVisitor {
 
    //--------------------------------------------------------------------------
 
    // Special traversal
 
    //--------------------------------------------------------------------------
 

	
 
    /// Will visit a statement with a hint about its wrapping statement. This is
 
    /// used to distinguish block statements with a wrapping synchronous
 
    /// statement from normal block statements.
 
    fn visit_stmt_with_hint(&mut self, ctx: &mut Ctx, id: StatementId, hint: Option<SynchronousStatementId>) -> VisitorResult {
 
        if let Statement::Block(block_stmt) = &ctx.heap[id] {
 
            let block_id = block_stmt.this;
 
            self.visit_block_stmt_with_hint(ctx, block_id, hint)
 
        } else {
 
            self.visit_stmt(ctx, id)
 
        }
 
    }
 

	
 
    fn visit_block_stmt_with_hint(&mut self, ctx: &mut Ctx, id: BlockStatementId, hint: Option<SynchronousStatementId>) -> VisitorResult {
 
        if self.performing_breadth_pass {
 
            // Performing a breadth pass, so don't traverse into the statements
 
            // of the block.
 
            return Ok(())
 
        }
 

	
 
        // Set parent scope and relative position in the parent scope. Remember
 
        // these values to set them back to the old values when we're done with
 
        // the traversal of the block's statements.
 
        let body = &mut ctx.heap[id];
 
        body.parent_scope = self.cur_scope.clone();
 
        body.relative_pos_in_parent = self.relative_pos_in_block;
 

	
 
        let old_scope = self.cur_scope.replace(match hint {
 
            Some(sync_id) => Scope::Synchronous((sync_id, id)),
 
            None => Scope::Regular(id),
 
        });
 
        let old_relative_pos = self.relative_pos_in_block;
 

	
 
        // Copy statement IDs into buffer
 
        let old_num_stmts = self.statement_buffer.len();
 
        {
 
            let body = &ctx.heap[id];
 
            self.statement_buffer.extend_from_slice(&body.statements);
 
        }
 
        let new_num_stmts = self.statement_buffer.len();
 

	
 
        // Perform the breadth-first pass. Its main purpose is to find labeled
 
        // statements such that we can find the `goto`-targets immediately when
 
        // performing the depth pass
 
        self.performing_breadth_pass = true;
 
        for stmt_idx in old_num_stmts..new_num_stmts {
 
            self.relative_pos_in_block = (stmt_idx - old_num_stmts) as u32;
 
            self.visit_stmt(ctx, self.statement_buffer[stmt_idx])?;
 
        }
 

	
 
        if !self.insert_buffer.is_empty() {
 
            let body = &mut ctx.heap[id];
 
            for (insert_idx, (pos, stmt)) in self.insert_buffer.drain(..).enumerate() {
 
                body.statements.insert(pos as usize + insert_idx, stmt);
 
            }
 
        }
 

	
 
        // And the depth pass. Because we're not actually visiting any inserted
 
        // nodes because we're using the statement buffer, we may safely use the
 
        // relative_pos_in_block counter.
 
        self.performing_breadth_pass = false;
 
        for stmt_idx in old_num_stmts..new_num_stmts {
 
            self.relative_pos_in_block = (stmt_idx - old_num_stmts) as u32;
 
            self.visit_stmt(ctx, self.statement_buffer[stmt_idx])?;
 
        }
 

	
 
        self.cur_scope = old_scope;
 
        self.relative_pos_in_block = old_relative_pos;
 

	
 
        // Pop statement buffer
 
        debug_assert!(self.insert_buffer.is_empty(), "insert buffer not empty after depth pass");
 
        self.statement_buffer.truncate(old_num_stmts);
 

	
 
        Ok(())
 
    }
 

	
 
    /// Visits a particular ParserType in the AST and resolves temporary and
 
    /// implicitly inferred types into the appropriate tree. Note that a
 
    /// ParserType node is a tree. Only call this function on the root node of
 
    /// that tree to prevent doing work more than once.
 
    fn visit_parser_type_without_buffer_cleanup(&mut self, ctx: &mut Ctx, id: ParserTypeId) -> VisitorResult {
 
        use ParserTypeVariant as PTV;
 
        debug_assert!(!self.performing_breadth_pass);
 

	
 
        let init_num_types = self.parser_type_buffer.len();
 
        self.parser_type_buffer.push(id);
 

	
 
        'resolve_loop: while self.parser_type_buffer.len() > init_num_types {
 
            let parser_type_id = self.parser_type_buffer.pop().unwrap();
 
            let parser_type = &ctx.heap[parser_type_id];
 

	
 
            let (symbolic_pos, symbolic_variant, num_inferred_to_allocate) = match &parser_type.variant {
 
                PTV::Message | PTV::Bool |
 
                PTV::Byte | PTV::Short | PTV::Int | PTV::Long |
 
                PTV::String |
 
                PTV::IntegerLiteral | PTV::Inferred => {
 
                    // Builtin types or types that do not require recursion
 
                    continue 'resolve_loop;
 
                },
 
                PTV::Array(subtype_id) |
 
                PTV::Input(subtype_id) |
 
                PTV::Output(subtype_id) => {
 
                    // Requires recursing
 
                    self.parser_type_buffer.push(*subtype_id);
 
                    continue 'resolve_loop;
 
                },
 
                PTV::Symbolic(symbolic) => {
 
                    // Retrieve poly_vars from function/component definition to
 
                    // match against.
 
                    let (definition_id, poly_vars) = match self.def_type {
 
                        DefinitionType::None => unreachable!(),
 
                        DefinitionType::Primitive(id) => (id.upcast(), &ctx.heap[id].poly_vars),
 
                        DefinitionType::Composite(id) => (id.upcast(), &ctx.heap[id].poly_vars),
 
                        DefinitionType::Function(id) => (id.upcast(), &ctx.heap[id].poly_vars),
 
                    };
 

	
 
                    let mut symbolic_variant = None;
 
                    for (poly_var_idx, poly_var) in poly_vars.iter().enumerate() {
 
                        if symbolic.identifier.matches_identifier(poly_var) {
 
                            // Type refers to a polymorphic variable.
 
                            // TODO: @hkt Maybe allow higher-kinded types?
 
                            if symbolic.identifier.get_poly_args().is_some() {
 
                                return Err(ParseError::new_error(
 
                                    &ctx.module.source, symbolic.identifier.position,
 
                                    "Polymorphic arguments to a polymorphic variable (higher-kinded types) are not allowed (yet)"
 
                                ));
 
                            }
 
                            symbolic_variant = Some(SymbolicParserTypeVariant::PolyArg(definition_id, poly_var_idx));
 
                        }
 
                    }
 

	
 
                    if let Some(symbolic_variant) = symbolic_variant {
 
                        // Identifier points to a polymorphic argument
 
                        (symbolic.identifier.position, symbolic_variant, 0)
 
                    } else {
 
                        // Must be a user-defined type, otherwise an error
 
                        let (found_type, ident_iter) = find_type_definition(
 
                            &ctx.symbols, &ctx.types, ctx.module.root_id, &symbolic.identifier
 
                        ).as_parse_error(&ctx.module.source)?;
 

	
 
                        // TODO: @function_ptrs: Allow function pointers at some
 
                        //  point in the future
 
                        if found_type.definition.type_class().is_proc_type() {
 
                            return Err(ParseError::new_error(
 
                                &ctx.module.source, symbolic.identifier.position,
 
                                &format!(
 
                                    "This identifier points to a {} type, expected a datatype",
 
                                    found_type.definition.type_class()
 
                                )
 
                            ));
 
                        }
 

	
 
                        // If the type is polymorphic then we have two cases: if
 
                        // the programmer did not specify the polyargs then we
 
                        // assume we're going to infer all of them. Otherwise we
 
                        // make sure that they match in count.
 
                        let (_, poly_args) = ident_iter.prev().unwrap();
 
                        let num_to_infer = match_polymorphic_args_to_vars(
 
                            found_type, poly_args, symbolic.identifier.position
 
                        ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                        (
 
                            symbolic.identifier.position,
 
                            SymbolicParserTypeVariant::Definition(found_type.ast_definition),
 
                            num_to_infer
 
                        )
 
                    }
 
                }
 
            };
 

	
 
            // If here then type is symbolic, perform a mutable borrow (and do
 
            // some rust shenanigans) to set the required information.
 
            for _ in 0..num_inferred_to_allocate {
 
                // TODO: @hack, not very user friendly to manually allocate
 
                //  `inferred` ParserTypes with the InputPosition of the
 
                //  symbolic type's identifier.
 
                // We reuse the `parser_type_buffer` to temporarily store these
 
                // and we'll take them out later
 
                self.parser_type_buffer.push(ctx.heap.alloc_parser_type(|this| ParserType{
 
                    this,
 
                    pos: symbolic_pos,
 
                    variant: ParserTypeVariant::Inferred,
 
                }));
 
            }
 

	
 
            if let PTV::Symbolic(symbolic) = &mut ctx.heap[parser_type_id].variant {
 
                if num_inferred_to_allocate != 0 {
 
                    symbolic.poly_args2.reserve(num_inferred_to_allocate);
 
                    for _ in 0..num_inferred_to_allocate {
 
                        symbolic.poly_args2.push(self.parser_type_buffer.pop().unwrap());
 
                    }
 
                } else if !symbolic.identifier.poly_args.is_empty() {
 
                    symbolic.poly_args2.extend(&symbolic.identifier.poly_args);
 
                    self.parser_type_buffer.extend(&symbolic.poly_args2);
 
                }
 
                symbolic.variant = Some(symbolic_variant);
 
            } else {
 
                unreachable!();
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // Utilities
 
    //--------------------------------------------------------------------------
 

	
 
    /// Adds a local variable to the current scope. It will also annotate the
 
    /// `Local` in the AST with its relative position in the block.
 
    fn checked_local_add(&mut self, ctx: &mut Ctx, relative_pos: u32, id: LocalId) -> Result<(), ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        // Make sure we do not conflict with any global symbols
 
        {
 
            let ident = &ctx.heap[id].identifier;
 
            if let Some(symbol) = ctx.symbols.resolve_symbol(ctx.module.root_id, &ident.value) {
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, ident.position, "Local variable declaration conflicts with symbol")
 
                        .with_postfixed_info(&ctx.module.source, symbol.position, "Conflicting symbol is found here")
 
                );
 
            }
 
        }
 

	
 
        let local = &mut ctx.heap[id];
 
        local.relative_pos_in_block = relative_pos;
 

	
 
        // Make sure we do not shadow any variables in any of the scopes. Note
 
        // that variables in parent scopes may be declared later
 
        let local = &ctx.heap[id];
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        let mut local_relative_pos = self.relative_pos_in_block;
 

	
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let block = &ctx.heap[scope.to_block()];
 
            for other_local_id in &block.locals {
 
                let other_local = &ctx.heap[*other_local_id];
 
                // Position check in case another variable with the same name
 
                // is defined in a higher-level scope, but later than the scope
 
                // in which the current variable resides.
 
                if local.this != *other_local_id &&
 
                    local_relative_pos >= other_local.relative_pos_in_block &&
 
                    local.identifier == other_local.identifier {
 
                    // Collision within this scope
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, local.position, "Local variable name conflicts with another variable")
 
                            .with_postfixed_info(&ctx.module.source, other_local.position, "Previous variable is found here")
 
                    );
 
                }
 
            }
 

	
 
            // Current scope is fine, move to parent scope if any
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if let Scope::Definition(definition_id) = scope {
 
                // At outer scope, check parameters of function/component
 
                for parameter_id in ctx.heap[*definition_id].parameters() {
 
                    let parameter = &ctx.heap[*parameter_id];
 
                    if local.identifier == parameter.identifier {
 
                        return Err(
 
                            ParseError::new_error(&ctx.module.source, local.position, "Local variable name conflicts with parameter")
 
                                .with_postfixed_info(&ctx.module.source, parameter.position, "Parameter definition is found here")
 
                        );
 
                    }
 
                }
 

	
 
                break;
 
            }
 

	
 
            // If here, then we are dealing with a block-like parent block
 
            local_relative_pos = ctx.heap[scope.to_block()].relative_pos_in_parent;
 
        }
 

	
 
        // No collisions at all
 
        let block = &mut ctx.heap[self.cur_scope.as_ref().unwrap().to_block()];
 
        block.locals.push(id);
 

	
 
        Ok(())
 
    }
 

	
 
    /// Finds a variable in the visitor's scope that must appear before the
 
    /// specified relative position within that block.
 
    fn find_variable(&self, ctx: &Ctx, mut relative_pos: u32, identifier: &NamespacedIdentifier) -> Result<VariableId, ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 
        debug_assert!(identifier.parts.len() == 1, "implement namespaced seeking of target associated with identifier");
 

	
 
        // TODO: May still refer to an alias of a global symbol using a single
 
        //  identifier in the namespace.
 
        // No need to use iterator over namespaces if here
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        
 
        loop {
 
            debug_assert!(scope.is_block());
 
            let block = &ctx.heap[scope.to_block()];
 
            
 
            for local_id in &block.locals {
 
                let local = &ctx.heap[*local_id];
 
                
 
                if local.relative_pos_in_block < relative_pos && identifier.matches_identifier(&local.identifier) {
 
                    return Ok(local_id.upcast());
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some());
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                // Definition scope, need to check arguments to definition
 
                match scope {
 
                    Scope::Definition(definition_id) => {
 
                        let definition = &ctx.heap[*definition_id];
 
                        for parameter_id in definition.parameters() {
 
                            let parameter = &ctx.heap[*parameter_id];
 
                            if identifier.matches_identifier(&parameter.identifier) {
 
                                return Ok(parameter_id.upcast());
 
                            }
 
                        }
 
                    },
 
                    _ => unreachable!(),
 
                }
 

	
 
                // Variable could not be found
 
                return Err(ParseError::new_error(
 
                    &ctx.module.source, identifier.position, "This variable is not declared"
 
                ));
 
            } else {
 
                relative_pos = block.relative_pos_in_parent;
 
            }
 
        }
 
    }
 

	
 
    /// Adds a particular label to the current scope. Will return an error if
 
    /// there is another label with the same name visible in the current scope.
 
    fn checked_label_add(&mut self, ctx: &mut Ctx, id: LabeledStatementId) -> Result<(), ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        // Make sure label is not defined within the current scope or any of the
 
        // parent scope.
 
        let label = &ctx.heap[id];
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 

	
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let block = &ctx.heap[scope.to_block()];
 
            for other_label_id in &block.labels {
 
                let other_label = &ctx.heap[*other_label_id];
 
                if other_label.label == label.label {
 
                    // Collision
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, label.position, "Label name conflicts with another label")
 
                            .with_postfixed_info(&ctx.module.source, other_label.position, "Other label is found here")
 
                    );
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                break;
 
            }
 
        }
 

	
 
        // No collisions
 
        let block = &mut ctx.heap[self.cur_scope.as_ref().unwrap().to_block()];
 
        block.labels.push(id);
 

	
 
        Ok(())
 
    }
 

	
 
    /// Finds a particular labeled statement by its identifier. Once found it
 
    /// will make sure that the target label does not skip over any variable
 
    /// declarations within the scope in which the label was found.
 
    fn find_label(&self, ctx: &Ctx, identifier: &Identifier) -> Result<LabeledStatementId, ParseError> {
 
        debug_assert!(self.cur_scope.is_some());
 

	
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        loop {
 
            debug_assert!(scope.is_block(), "scope is not a block");
 
            let relative_scope_pos = ctx.heap[scope.to_block()].relative_pos_in_parent;
 

	
 
            let block = &ctx.heap[scope.to_block()];
 
            for label_id in &block.labels {
 
                let label = &ctx.heap[*label_id];
 
                if label.label == *identifier {
 
                    for local_id in &block.locals {
 
                        // TODO: Better to do this in control flow analysis, it
 
                        //  is legal to skip over a variable declaration if it
 
                        //  is not actually being used. I might be missing
 
                        //  something here when laying out the bytecode...
 
                        let local = &ctx.heap[*local_id];
 
                        if local.relative_pos_in_block > relative_scope_pos && local.relative_pos_in_block < label.relative_pos_in_block {
 
                            return Err(
 
                                ParseError::new_error(&ctx.module.source, identifier.position, "This target label skips over a variable declaration")
 
                                    .with_postfixed_info(&ctx.module.source, label.position, "Because it jumps to this label")
 
                                    .with_postfixed_info(&ctx.module.source, local.position, "Which skips over this variable")
 
                            );
 
                        }
 
                    }
 
                    return Ok(*label_id);
 
                }
 
            }
 

	
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                return Err(ParseError::new_error(&ctx.module.source, identifier.position, "Could not find this label"));
 
            }
 

	
 
        }
 
    }
 

	
 
    /// Finds a particular symbol in the symbol table which must correspond to
 
    /// a definition of a particular type.
 
    // Note: root_id, symbols and types passed in explicitly to prevent
 
    //  borrowing errors
 
    fn find_symbol_of_type<'t>(
 
        &self, source: &InputSource, root_id: RootId, symbols: &SymbolTable, 
 
        types: &'t TypeTable, identifier: &NamespacedIdentifier, 
 
        expected_type_class: TypeClass
 
    ) -> Result<&'t DefinedType, ParseError> {
 
        // Find symbol associated with identifier
 
        let (find_result, _) = find_type_definition(symbols, types, root_id, identifier)
 
            .as_parse_error(source)?;
 

	
 
        let definition_type_class = find_result.definition.type_class();
 
        if expected_type_class != definition_type_class {
 
            return Err(ParseError::new_error(
 
                source, identifier.position,
 
                &format!(
 
                    "Expected to find a {}, this symbol points to a {}",
 
                    expected_type_class, definition_type_class
 
                )
 
            ))
 
        }
 

	
 
        Ok(find_result)
 
    }
 

	
 
    /// Finds a particular enum/union using a namespaced identifier. We allow 
 
    /// for one more element to exist in the namespaced identifier that 
 
    /// supposedly resolves to the enum/union variant.
 
    fn find_symbol_of_type_variant<'t, 'i>(
 
        &self, source: &InputSource, root_id: RootId, symbols: &SymbolTable,
 
        types: &'t TypeTable, identifier: &'i NamespacedIdentifier,
 
        expected_type_class: TypeClass
 
    ) -> Result<(&'t DefinedType, NamespacedIdentifierIter<'i>), ParseError> {
 
        debug_assert!(expected_type_class == TypeClass::Enum || expected_type_class == TypeClass::Union);
 
        let (symbol, mut ident_iter) = symbols.resolve_namespaced_identifier(root_id, identifier);
 

	
 
        if symbol.is_none() {
 
            return Err(ParseError::new_error(
 
                source, identifier.position, 
 
                "Could not resolve this identifier to a symbol"
 
            ));
 
        }
 

	
 
        let symbol = symbol.unwrap();
 
        match symbol.symbol {
 
            Symbol::Namespace(_) => {
 
                return Err(ParseError::new_error(
 
                    source, identifier.position, 
 
                    "This identifier was resolved to a namespace instead of a type"
 
                ))
 
            },
 
            Symbol::Definition((_, definition_id)) => {
 
                let definition = types.get_base_definition(&definition_id);
 
                debug_assert!(definition.is_some());
 
                let definition = definition.unwrap();
 

	
 
                let definition_type_class = definition.definition.type_class();
 
                if expected_type_class != definition_type_class {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "Expected to find a {}, this symbols points to a {}",
 
                            expected_type_class, definition_type_class
 
                        )
 
                    ));
 
                }
 

	
 
                // Make sure we have a variant (that doesn't contain any 
 
                // polymorphic args)
 
                let next_part = ident_iter.next();
 
                if next_part.is_none() {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "This identifier points to the type '{}', did you mean to instantiate a variant?",
 
                            String::from_utf8_lossy(&identifier.value)
 
                        )
 
                    ));
 
                }
 
                let (_, next_polyargs) = next_part.unwrap();
 

	
 
                // Now we make sure that there aren't even more identifiers, and
 
                // make sure that the variant does not contain any polymorphic
 
                // arguments. In that case we can simplify the later visit of
 
                // the (optional) polymorphic args of the enum.
 
                let returned_section = ident_iter.returned_section();
 
                if ident_iter.num_remaining() != 0 {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        &format!(
 
                            "Too many identifiers, did you mean to write '{}'",
 
                            &String::from_utf8_lossy(returned_section)
 
                        )
 
                    ));
 
                }
 

	
 
                if next_polyargs.is_some() {
 
                    return Err(ParseError::new_error(
 
                        source, identifier.position,
 
                        "Encountered polymorphic args to an enum variant. These can only be specified for the enum type."
 
                    ))
 
                }
 

	
 
                // We're absolutely fine
 
                Ok((definition, ident_iter))
 
            }
 
        }
 
    }
 

	
 
    /// This function will check if the provided while statement ID has a block
 
    /// statement that is one of our current parents.
 
    fn has_parent_while_scope(&self, ctx: &Ctx, id: WhileStatementId) -> bool {
 
        debug_assert!(self.cur_scope.is_some());
 
        let mut scope = self.cur_scope.as_ref().unwrap();
 
        let while_stmt = &ctx.heap[id];
 
        loop {
 
            debug_assert!(scope.is_block());
 
            let block = scope.to_block();
 
            if while_stmt.body == block.upcast() {
 
                return true;
 
            }
 

	
 
            let block = &ctx.heap[block];
 
            debug_assert!(block.parent_scope.is_some(), "block scope does not have a parent");
 
            scope = block.parent_scope.as_ref().unwrap();
 
            if !scope.is_block() {
 
                return false;
 
            }
 
        }
 
    }
 

	
 
    /// This function should be called while dealing with break/continue
 
    /// statements. It will try to find the targeted while statement, using the
 
    /// target label if provided. If a valid target is found then the loop's
 
    /// ID will be returned, otherwise a parsing error is constructed.
 
    /// The provided input position should be the position of the break/continue
 
    /// statement.
 
    fn resolve_break_or_continue_target(&self, ctx: &Ctx, position: InputPosition, label: &Option<Identifier>) -> Result<WhileStatementId, ParseError> {
 
        let target = match label {
 
            Some(label) => {
 
                let target_id = self.find_label(ctx, label)?;
 

	
 
                // Make sure break target is a while statement
 
                let target = &ctx.heap[target_id];
 
                if let Statement::While(target_stmt) = &ctx.heap[target.body] {
 
                    // Even though we have a target while statement, the break might not be
 
                    // present underneath this particular labeled while statement
 
                    if !self.has_parent_while_scope(ctx, target_stmt.this) {
 
                        ParseError::new_error(&ctx.module.source, label.position, "Break statement is not nested under the target label's while statement")
 
                            .with_postfixed_info(&ctx.module.source, target.position, "The targeted label is found here");
 
                    }
 

	
 
                    target_stmt.this
 
                } else {
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, label.position, "Incorrect break target label, it must target a while loop")
 
                            .with_postfixed_info(&ctx.module.source, target.position, "The targeted label is found here")
 
                    );
 
                }
 
            },
 
            None => {
 
                // Use the enclosing while statement, the break must be
 
                // nested within that while statement
 
                if self.in_while.is_none() {
 
                    return Err(
 
                        ParseError::new_error(&ctx.module.source, position, "Break statement is not nested under a while loop")
 
                    );
 
                }
 

	
 
                self.in_while.unwrap()
 
            }
 
        };
 

	
 
        // We have a valid target for the break statement. But we need to
 
        // make sure we will not break out of a synchronous block
 
        {
 
            let target_while = &ctx.heap[target];
 
            if target_while.in_sync != self.in_sync {
 
                // Break is nested under while statement, so can only escape a
 
                // sync block if the sync is nested inside the while statement.
 
                debug_assert!(self.in_sync.is_some());
 
                let sync_stmt = &ctx.heap[self.in_sync.unwrap()];
 
                return Err(
 
                    ParseError::new_error(&ctx.module.source, position, "Break may not escape the surrounding synchronous block")
 
                        .with_postfixed_info(&ctx.module.source, target_while.position, "The break escapes out of this loop")
 
                        .with_postfixed_info(&ctx.module.source, sync_stmt.position, "And would therefore escape this synchronous block")
 
                );
 
            }
 
        }
 

	
 
        Ok(target)
 
    }
 

	
 
    // TODO: @cleanup, merge with function below
 
    fn visit_call_poly_args(&mut self, ctx: &mut Ctx, call_id: CallExpressionId) -> VisitorResult {
 
        // TODO: @token Revisit when tokenizer is implemented
 
        let call_expr = &mut ctx.heap[call_id];
 
        if let Method::Symbolic(symbolic) = &mut call_expr.method {
 
            if let Some(poly_args) = symbolic.identifier.get_poly_args() {
 
                call_expr.poly_args.extend(poly_args);
 
            }
 
        }
 

	
 
        let call_expr = &ctx.heap[call_id];
 

	
 
        // Determine the polyarg signature
 
        let num_expected_poly_args = match &call_expr.method {
 
            Method::Create => {
 
                0
 
            },
 
            Method::Fires => {
 
                1
 
            },
 
            Method::Get => {
 
                1
 
            },
 
            Method::Put => {
 
                1
 
            }
 
            Method::Symbolic(symbolic) => {
 
                // Retrieve type and make sure number of specified polymorphic 
 
                // arguments is correct
 

	
 
                let definition = &ctx.heap[symbolic.definition.unwrap()];
 
                match definition {
 
                    Definition::Function(definition) => definition.poly_vars.len(),
 
                    Definition::Component(definition) => definition.poly_vars.len(),
 
                    _ => {
 
                        debug_assert!(false, "expected function or component definition while visiting call poly args");
 
                        unreachable!();
 
                    }
 
                }
 
            }
 
        };
 

	
 
        // We allow zero polyargs to imply all args are inferred. Otherwise the
 
        // number of arguments must be equal
 
        if call_expr.poly_args.is_empty() {
 
            if num_expected_poly_args != 0 {
 
                // Infer all polyargs
 
                // TODO: @cleanup Not nice to use method position as implicitly
 
                //  inferred parser type pos.
 
                let pos = call_expr.position();
 
                for _ in 0..num_expected_poly_args {
 
                    self.parser_type_buffer.push(ctx.heap.alloc_parser_type(|this| ParserType {
 
                        this,
 
                        pos,
 
                        variant: ParserTypeVariant::Inferred,
 
                    }));
 
                }
 

	
 
                let call_expr = &mut ctx.heap[call_id];
 
                call_expr.poly_args.reserve(num_expected_poly_args);
 
                for _ in 0..num_expected_poly_args {
 
                    call_expr.poly_args.push(self.parser_type_buffer.pop().unwrap());
 
                }
 
            }
 
            Ok(())
 
        } else if call_expr.poly_args.len() == num_expected_poly_args {
 
            // Number of args is not 0, so parse all the specified ParserTypes
 
            let old_num_types = self.parser_type_buffer.len();
 
            self.parser_type_buffer.extend(&call_expr.poly_args);
 
            while self.parser_type_buffer.len() > old_num_types {
 
                let parser_type_id = self.parser_type_buffer.pop().unwrap();
 
                self.visit_parser_type(ctx, parser_type_id)?;
 
            }
 
            self.parser_type_buffer.truncate(old_num_types);
 
            Ok(())
 
        } else {
 
            return Err(ParseError::new_error(
 
                &ctx.module.source, call_expr.position,
 
                &format!(
 
                    "Expected {} polymorphic arguments (or none, to infer them), but {} were specified",
 
                    num_expected_poly_args, call_expr.poly_args.len()
 
                )
 
            ));
 
        }
 
    }
 

	
 
    fn visit_literal_poly_args(&mut self, ctx: &mut Ctx, lit_id: LiteralExpressionId) -> VisitorResult {
 
        // TODO: @token Revisit when tokenizer is implemented
 
        let literal_expr = &mut ctx.heap[lit_id];
 
        match &mut literal_expr.value {
 
            Literal::Struct(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            },
 
            Literal::Enum(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            },
 
            Literal::Union(literal) => {
 
                literal.poly_args2.extend(&literal.identifier.poly_args);
 
            }
 
            _ => {
 
                debug_assert!(false, "called visit_literal_poly_args on a non-polymorphic literal");
 
                unreachable!();
 
            }
 
        }
 

	
 
        let literal_expr = &ctx.heap[lit_id];
 
        let literal_pos = literal_expr.position;
 
        let (num_poly_args_to_infer, poly_args_to_visit) = match &literal_expr.value {
 
            Literal::Null | Literal::False | Literal::True |
 
            Literal::Character(_) | Literal::Integer(_) => {
 
                // Not really an error, but a programmer error as we're likely
 
                // doing work twice
 
                unreachable!();
 
            },
 
            Literal::Struct(literal) => {
 
                // Retrieve type and make sure number of specified polymorphic
 
                // arguments is correct.
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            },
 
            Literal::Enum(literal) => {
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            },
 
            Literal::Union(literal) => {
 
                let defined_type = ctx.types.get_base_definition(literal.definition.as_ref().unwrap())
 
                    .unwrap();
 
                let maybe_poly_args = literal.identifier.get_poly_args();
 
                let num_to_infer = match_polymorphic_args_to_vars(
 
                    defined_type, maybe_poly_args, literal.identifier.position
 
                ).as_parse_error(&ctx.heap, &ctx.module.source)?;
 

	
 
                (num_to_infer, &literal.poly_args2)
 
            }
 
        };
 

	
 
        // Visit all specified parser types in the polymorphic arguments
 
        let old_num_types = self.parser_type_buffer.len();
 
        self.parser_type_buffer.extend(poly_args_to_visit);
 
        while self.parser_type_buffer.len() > old_num_types {
 
            let parser_type_id = self.parser_type_buffer.pop().unwrap();
 
            self.visit_parser_type(ctx, parser_type_id)?;
 
        }
 
        self.parser_type_buffer.truncate(old_num_types);
 

	
 
        if num_poly_args_to_infer != 0 {
 
            for _ in 0..num_poly_args_to_infer {
 
                self.parser_type_buffer.push(ctx.heap.alloc_parser_type(|this| ParserType{
 
                    this, pos: literal_pos, variant: ParserTypeVariant::Inferred
 
                }));
 
            }
 

	
 
            let poly_args = match &mut ctx.heap[lit_id].value {
 
                Literal::Struct(literal) => &mut literal.poly_args2,
 
                Literal::Enum(literal) => &mut literal.poly_args2,
 
                Literal::Union(literal) => &mut literal.poly_args2,
 
                _ => unreachable!(),
 
            };
 
            poly_args.reserve(num_poly_args_to_infer);
 
            for _ in 0..num_poly_args_to_infer {
 
                poly_args.push(self.parser_type_buffer.pop().unwrap());
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 
}
 
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