Changeset - a82fb2b1f7f9
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MH - 4 years ago 2021-03-14 18:23:45
contact@maxhenger.nl
WIP on type inference
5 files changed with 347 insertions and 42 deletions:
0 comments (0 inline, 0 general)
src/protocol/ast.rs
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// 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 super::containers::StringAllocator;
 

	
 
// TODO: @cleanup, transform wrapping types into type aliases where possible
 
use crate::protocol::inputsource::*;
 

	
 
/// 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, $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]
 
            }
 
        }
 
    }
 
}
 

	
 
/// 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, serde::Serialize, serde::Deserialize)]
 
        pub struct $name (pub(crate) $parent);
 

	
 
        impl $name {
 
            pub fn upcast(self) -> $parent {
 
                self.0
 
            }
 
        }
 
    };
 
    // Variant where we define the type, and the Index and IndexMut traits
 
    ($name:ident, $parent:ty, $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!()
 
                }
 
            }
 
        }
 
    }
 
}
 

	
 
define_aliased_ast_id!(RootId, Id<Root>, Root, protocol_descriptions);
 
define_aliased_ast_id!(PragmaId, Id<Pragma>, Pragma, pragmas);
 
define_aliased_ast_id!(ImportId, Id<Import>, Import, imports);
 
define_aliased_ast_id!(ParserTypeId, Id<ParserType>, ParserType, parser_types);
 

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

	
 
define_aliased_ast_id!(DefinitionId, Id<Definition>, Definition, definitions);
 
define_new_ast_id!(StructId, DefinitionId, StructDefinition, Definition::Struct, definitions);
 
define_new_ast_id!(EnumId, DefinitionId, EnumDefinition, Definition::Enum, definitions);
 
define_new_ast_id!(ComponentId, DefinitionId, Component, Definition::Component, definitions);
 
define_new_ast_id!(FunctionId, DefinitionId, Function, Definition::Function, definitions);
 

	
 
define_aliased_ast_id!(StatementId, Id<Statement>, Statement, statements);
 
define_new_ast_id!(BlockStatementId, StatementId, BlockStatement, Statement::Block, statements);
 
define_new_ast_id!(LocalStatementId, StatementId, LocalStatement, Statement::Local, statements);
 
define_new_ast_id!(MemoryStatementId, LocalStatementId);
 
define_new_ast_id!(ChannelStatementId, LocalStatementId);
 
define_new_ast_id!(SkipStatementId, StatementId, SkipStatement, Statement::Skip, statements);
 
define_new_ast_id!(LabeledStatementId, StatementId, LabeledStatement, Statement::Labeled, statements);
 
define_new_ast_id!(IfStatementId, StatementId, IfStatement, Statement::If, statements);
 
define_new_ast_id!(EndIfStatementId, StatementId, EndIfStatement, Statement::EndIf, statements);
 
define_new_ast_id!(WhileStatementId, StatementId, WhileStatement, Statement::While, statements);
 
define_new_ast_id!(EndWhileStatementId, StatementId, EndWhileStatement, Statement::EndWhile, statements);
 
define_new_ast_id!(BreakStatementId, StatementId, BreakStatement, Statement::Break, statements);
 
define_new_ast_id!(ContinueStatementId, StatementId, ContinueStatement, Statement::Continue, statements);
 
define_new_ast_id!(SynchronousStatementId, StatementId, SynchronousStatement, Statement::Synchronous, statements);
 
define_new_ast_id!(EndSynchronousStatementId, StatementId, EndSynchronousStatement, Statement::EndSynchronous, statements);
 
define_new_ast_id!(ReturnStatementId, StatementId, ReturnStatement, Statement::Return, statements);
 
define_new_ast_id!(AssertStatementId, StatementId, AssertStatement, Statement::Assert, statements);
 
define_new_ast_id!(GotoStatementId, StatementId, GotoStatement, Statement::Goto, statements);
 
define_new_ast_id!(NewStatementId, StatementId, NewStatement, Statement::New, statements);
 
define_new_ast_id!(PutStatementId, StatementId, PutStatement, Statement::Put, statements);
 
define_new_ast_id!(ExpressionStatementId, StatementId, ExpressionStatement, Statement::Expression, statements);
 

	
 
define_aliased_ast_id!(ExpressionId, Id<Expression>, Expression, expressions);
 
define_new_ast_id!(AssignmentExpressionId, ExpressionId, AssignmentExpression, Expression::Assignment, expressions);
 
define_new_ast_id!(ConditionalExpressionId, ExpressionId, ConditionalExpression, Expression::Conditional, expressions);
 
define_new_ast_id!(BinaryExpressionId, ExpressionId, BinaryExpression, Expression::Binary, expressions);
 
define_new_ast_id!(UnaryExpressionId, ExpressionId, UnaryExpression, Expression::Unary, expressions);
 
define_new_ast_id!(IndexingExpressionId, ExpressionId, IndexingExpression, Expression::Indexing, expressions);
 
define_new_ast_id!(SlicingExpressionId, ExpressionId, SlicingExpression, Expression::Slicing, expressions);
 
define_new_ast_id!(SelectExpressionId, ExpressionId, SelectExpression, Expression::Select, expressions);
 
define_new_ast_id!(ArrayExpressionId, ExpressionId, ArrayExpression, Expression::Array, expressions);
 
define_new_ast_id!(ConstantExpressionId, ExpressionId, ConstantExpression, Expression::Constant, expressions);
 
define_new_ast_id!(CallExpressionId, ExpressionId, CallExpression, Expression::Call, expressions);
 
define_new_ast_id!(VariableExpressionId, ExpressionId, VariableExpression, Expression::Variable, expressions);
 

	
 
// TODO: @cleanup - pub qualifiers can be removed once done
 
#[derive(Debug, serde::Serialize, serde::Deserialize)]
 
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>,
 
    identifiers: Arena<Identifier>,
 
    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(),
 
            identifiers: Arena::new(),
 
            parser_types: Arena::new(),
 
            variables: Arena::new(),
 
            definitions: Arena::new(),
 
            statements: Arena::new(),
 
            expressions: Arena::new(),
 
        }
 
    }
 
    pub fn alloc_parser_type(
 
        &mut self,
 
        f: impl FnOnce(ParserTypeId) -> ParserType,
 
    ) -> ParserTypeId {
 
        self.parser_types.alloc_with_id(|id| f(id))
 
    }
 

	
 
    pub fn alloc_parameter(&mut self, f: impl FnOnce(ParameterId) -> Parameter) -> ParameterId {
 
        ParameterId(
 
            self.variables.alloc_with_id(|id| Variable::Parameter(f(ParameterId(id)))),
 
        )
 
    }
 
    pub fn alloc_local(&mut self, f: impl FnOnce(LocalId) -> Local) -> LocalId {
 
        LocalId(
 
            self.variables.alloc_with_id(|id| Variable::Local(f(LocalId(id)))),
 
        )
 
    }
 
    pub fn alloc_assignment_expression(
 
        &mut self,
 
        f: impl FnOnce(AssignmentExpressionId) -> AssignmentExpression,
 
    ) -> AssignmentExpressionId {
 
        AssignmentExpressionId(
 
            self.expressions.alloc_with_id(|id| {
 
                Expression::Assignment(f(AssignmentExpressionId(id)))
 
            })
 
        )
 
    }
 
    pub fn alloc_conditional_expression(
 
        &mut self,
 
        f: impl FnOnce(ConditionalExpressionId) -> ConditionalExpression,
 
    ) -> ConditionalExpressionId {
 
        ConditionalExpressionId(
 
            self.expressions.alloc_with_id(|id| {
 
                Expression::Conditional(f(ConditionalExpressionId(id)))
 
            })
 
        )
 
    }
 
    pub fn alloc_binary_expression(
 
        &mut self,
 
        f: impl FnOnce(BinaryExpressionId) -> BinaryExpression,
 
    ) -> BinaryExpressionId {
 
        BinaryExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Binary(f(BinaryExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_unary_expression(
 
        &mut self,
 
        f: impl FnOnce(UnaryExpressionId) -> UnaryExpression,
 
    ) -> UnaryExpressionId {
 
        UnaryExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Unary(f(UnaryExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_slicing_expression(
 
        &mut self,
 
        f: impl FnOnce(SlicingExpressionId) -> SlicingExpression,
 
    ) -> SlicingExpressionId {
 
        SlicingExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Slicing(f(SlicingExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_indexing_expression(
 
        &mut self,
 
        f: impl FnOnce(IndexingExpressionId) -> IndexingExpression,
 
    ) -> IndexingExpressionId {
 
        IndexingExpressionId(
 
            self.expressions.alloc_with_id(|id| {
 
                Expression::Indexing(f(IndexingExpressionId(id)))
 
            }),
 
        )
 
    }
 
    pub fn alloc_select_expression(
 
        &mut self,
 
        f: impl FnOnce(SelectExpressionId) -> SelectExpression,
 
    ) -> SelectExpressionId {
 
        SelectExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Select(f(SelectExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_array_expression(
 
        &mut self,
 
        f: impl FnOnce(ArrayExpressionId) -> ArrayExpression,
 
    ) -> ArrayExpressionId {
 
        ArrayExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Array(f(ArrayExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_constant_expression(
 
        &mut self,
 
        f: impl FnOnce(ConstantExpressionId) -> ConstantExpression,
 
    ) -> ConstantExpressionId {
 
        ConstantExpressionId(
 
            self.expressions.alloc_with_id(|id| {
 
                Expression::Constant(f(ConstantExpressionId(id)))
 
            }),
 
        )
 
    }
 
    pub fn alloc_call_expression(
 
        &mut self,
 
        f: impl FnOnce(CallExpressionId) -> CallExpression,
 
    ) -> CallExpressionId {
 
        CallExpressionId(
 
            self.expressions
 
                .alloc_with_id(|id| Expression::Call(f(CallExpressionId(id)))),
 
        )
 
    }
 
    pub fn alloc_variable_expression(
 
        &mut self,
 
        f: impl FnOnce(VariableExpressionId) -> VariableExpression,
 
    ) -> VariableExpressionId {
 
        VariableExpressionId(
 
            self.expressions.alloc_with_id(|id| {
 
                Expression::Variable(f(VariableExpressionId(id)))
 
            }),
 
        )
 
    }
 
    pub fn alloc_block_statement(
 
        &mut self,
 
        f: impl FnOnce(BlockStatementId) -> BlockStatement,
 
    ) -> BlockStatementId {
 
        BlockStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Block(f(BlockStatementId(id)))),
 
        )
 
    }
 
    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)))
 
            ))
 
        })))
 
    }
 
    pub fn alloc_skip_statement(
 
        &mut self,
 
        f: impl FnOnce(SkipStatementId) -> SkipStatement,
 
    ) -> SkipStatementId {
 
        SkipStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Skip(f(SkipStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_if_statement(
 
        &mut self,
 
        f: impl FnOnce(IfStatementId) -> IfStatement,
 
    ) -> IfStatementId {
 
        IfStatementId(
 
            self.statements.alloc_with_id(|id| Statement::If(f(IfStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_end_if_statement(
 
        &mut self,
 
        f: impl FnOnce(EndIfStatementId) -> EndIfStatement,
 
    ) -> EndIfStatementId {
 
        EndIfStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::EndIf(f(EndIfStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_while_statement(
 
        &mut self,
 
        f: impl FnOnce(WhileStatementId) -> WhileStatement,
 
    ) -> WhileStatementId {
 
        WhileStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::While(f(WhileStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_end_while_statement(
 
        &mut self,
 
        f: impl FnOnce(EndWhileStatementId) -> EndWhileStatement,
 
    ) -> EndWhileStatementId {
 
        EndWhileStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::EndWhile(f(EndWhileStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_break_statement(
 
        &mut self,
 
        f: impl FnOnce(BreakStatementId) -> BreakStatement,
 
    ) -> BreakStatementId {
 
        BreakStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Break(f(BreakStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_continue_statement(
 
        &mut self,
 
        f: impl FnOnce(ContinueStatementId) -> ContinueStatement,
 
    ) -> ContinueStatementId {
 
        ContinueStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Continue(f(ContinueStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_synchronous_statement(
 
        &mut self,
 
        f: impl FnOnce(SynchronousStatementId) -> SynchronousStatement,
 
    ) -> SynchronousStatementId {
 
        SynchronousStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::Synchronous(f(SynchronousStatementId(id)))
 
        }))
 
    }
 
    pub fn alloc_end_synchronous_statement(
 
        &mut self,
 
        f: impl FnOnce(EndSynchronousStatementId) -> EndSynchronousStatement,
 
    ) -> EndSynchronousStatementId {
 
        EndSynchronousStatementId(self.statements.alloc_with_id(|id| {
 
            Statement::EndSynchronous(f(EndSynchronousStatementId(id)))
 
        }))
 
    }
 
    pub fn alloc_return_statement(
 
        &mut self,
 
        f: impl FnOnce(ReturnStatementId) -> ReturnStatement,
 
    ) -> ReturnStatementId {
 
        ReturnStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Return(f(ReturnStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_assert_statement(
 
        &mut self,
 
        f: impl FnOnce(AssertStatementId) -> AssertStatement,
 
    ) -> AssertStatementId {
 
        AssertStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Assert(f(AssertStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_goto_statement(
 
        &mut self,
 
        f: impl FnOnce(GotoStatementId) -> GotoStatement,
 
    ) -> GotoStatementId {
 
        GotoStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Goto(f(GotoStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_new_statement(
 
        &mut self,
 
        f: impl FnOnce(NewStatementId) -> NewStatement,
 
    ) -> NewStatementId {
 
        NewStatementId(
 
            self.statements.alloc_with_id(|id| Statement::New(f(NewStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_put_statement(
 
        &mut self,
 
        f: impl FnOnce(PutStatementId) -> PutStatement,
 
    ) -> PutStatementId {
 
        PutStatementId(
 
            self.statements.alloc_with_id(|id| Statement::Put(f(PutStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_labeled_statement(
 
        &mut self,
 
        f: impl FnOnce(LabeledStatementId) -> LabeledStatement,
 
    ) -> LabeledStatementId {
 
        LabeledStatementId(
 
            self.statements
 
                .alloc_with_id(|id| Statement::Labeled(f(LabeledStatementId(id)))),
 
        )
 
    }
 
    pub fn alloc_expression_statement(
 
        &mut self,
 
        f: impl FnOnce(ExpressionStatementId) -> ExpressionStatement,
 
    ) -> ExpressionStatementId {
 
        ExpressionStatementId(
 
            self.statements.alloc_with_id(|id| {
 
                Statement::Expression(f(ExpressionStatementId(id)))
 
            }),
 
        )
 
    }
 
    pub fn alloc_struct_definition(&mut self, f: impl FnOnce(StructId) -> StructDefinition) -> StructId {
 
        StructId(self.definitions.alloc_with_id(|id| {
 
            Definition::Struct(f(StructId(id)))
 
        }))
 
    }
 
    pub fn alloc_enum_definition(&mut self, f: impl FnOnce(EnumId) -> EnumDefinition) -> EnumId {
 
        EnumId(self.definitions.alloc_with_id(|id| {
 
            Definition::Enum(f(EnumId(id)))
 
        }))
 
    }
 
    pub fn alloc_component(&mut self, f: impl FnOnce(ComponentId) -> Component) -> ComponentId {
 
        ComponentId(self.definitions.alloc_with_id(|id| {
 
            Definition::Component(f(ComponentId(id)))
 
        }))
 
    }
 
    pub fn alloc_function(&mut self, f: impl FnOnce(FunctionId) -> Function) -> FunctionId {
 
        FunctionId(
 
            self.definitions
 
                .alloc_with_id(|id| Definition::Function(f(FunctionId(id)))),
 
        )
 
    }
 
    pub fn alloc_pragma(&mut self, f: impl FnOnce(PragmaId) -> Pragma) -> PragmaId {
 
        self.pragmas.alloc_with_id(|id| f(id))
 
    }
 
    pub fn alloc_import(&mut self, f: impl FnOnce(ImportId) -> Import) -> ImportId {
 
        self.imports.alloc_with_id(|id| f(id))
 
    }
 
    pub fn alloc_protocol_description(&mut self, f: impl FnOnce(RootId) -> Root) -> RootId {
 
        self.protocol_descriptions.alloc_with_id(|id| f(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, serde::Serialize, serde::Deserialize)]
 
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
 
    }
 
}
 

	
 
impl SyntaxElement for Root {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct PragmaVersion {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub version: u64,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct PragmaModule {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub value: Vec<u8>,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct PragmaOld {
 
    pub this: PragmaId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub value: Vec<u8>,
 
}
 

	
 
impl SyntaxElement for PragmaOld {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

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

	
 
impl SyntaxElement for Import {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            Import::Module(m) => m.position,
 
            Import::Symbols(m) => m.position
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ImportModule {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub module_name: Vec<u8>,
 
    pub alias: Vec<u8>,
 
    // Phase 2: module resolving
 
    pub module_id: Option<RootId>,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct AliasedSymbol {
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub name: Vec<u8>,
 
    pub alias: Vec<u8>,
 
    // Phase 2: symbol resolving
 
    pub definition_id: Option<DefinitionId>,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ImportSymbols {
 
    pub this: ImportId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub module_name: Vec<u8>,
 
    // Phase 2: module resolving
 
    pub module_id: Option<RootId>,
 
    // Phase 1&2
 
    // if symbols is empty, then we implicitly import all symbols without any
 
    // aliases for them. If it is not empty, then symbols are explicitly
 
    // specified, and optionally given an alias.
 
    pub symbols: Vec<AliasedSymbol>,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct Identifier {
 
    pub position: InputPosition,
 
    pub value: Vec<u8>
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct NamespacedIdentifier {
 
    pub position: InputPosition,
 
    pub num_namespaces: u8,
 
    pub value: Vec<u8>,
 
}
 

	
 
impl NamespacedIdentifier {
 
    pub(crate) fn iter(&self) -> NamespacedIdentifierIter {
 
        NamespacedIdentifierIter{
 
            value: &self.value,
 
            cur_offset: 0,
 
            num_returned: 0,
 
            num_total: self.num_namespaces
 
        }
 
    }
 
}
 

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

	
 
// TODO: Just keep ref to NamespacedIdentifier
 
pub(crate) struct NamespacedIdentifierIter<'a> {
 
    value: &'a Vec<u8>,
 
    cur_offset: usize,
 
    num_returned: u8,
 
    num_total: u8,
 
}
 

	
 
impl<'a> NamespacedIdentifierIter<'a> {
 
    pub(crate) fn num_returned(&self) -> u8 {
 
        return self.num_returned;
 
    }
 
    pub(crate) fn num_remaining(&self) -> u8 {
 
        return self.num_total - self.num_returned
 
    }
 
}
 

	
 
impl<'a> Iterator for NamespacedIdentifierIter<'a> {
 
    type Item = &'a [u8];
 
    fn next(&mut self) -> Option<Self::Item> {
 
        if self.cur_offset >= self.value.len() {
 
            debug_assert_eq!(self.num_returned, self.num_total);
 
            None
 
        } else {
 
            debug_assert!(self.num_returned < self.num_total);
 
            let start = self.cur_offset;
 
            let mut end = start;
 
            while end < self.value.len() - 1 {
 
                if self.value[end] == b':' && self.value[end + 1] == b':' {
 
                    self.cur_offset = end + 2;
 
                    self.num_returned += 1;
 
                    return Some(&self.value[start..end]);
 
                }
 
                end += 1;
 
            }
 

	
 
            // If NamespacedIdentifier is constructed properly, then we cannot
 
            // end with "::" in the value, so
 
            debug_assert!(end == 0 || (self.value[end - 1] != b':' && self.value[end] != b':'));
 
            debug_assert_eq!(self.num_returned + 1, self.num_total);
 
            self.cur_offset = self.value.len();
 
            self.num_returned += 1;
 
            return Some(&self.value[start..]);
 
        }
 
    }
 
}
 

	
 
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))
 
    }
 
}
 

	
 
/// TODO: @cleanup Maybe handle this differently, preallocate in heap? The
 
///     reason I'm handling it like this now is so we don't allocate types in
 
///     the `Arena` structure if they're the common types defined here.
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub enum ParserTypeVariant {
 
    // Basic builtin
 
    Message,
 
    Bool,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    String,
 
    // Literals (need to get concrete builtin type during typechecking)
 
    IntegerLiteral,
 
    Inferred,
 
    // Complex builtins
 
    Array(ParserTypeId), // array of a type
 
    Input(ParserTypeId), // typed input endpoint of a channel
 
    Output(ParserTypeId), // typed output endpoint of a channel
 
    Symbolic(SymbolicParserType), // symbolic type (definition or polyarg)
 
}
 

	
 
impl ParserTypeVariant {
 
    pub(crate) fn supports_polymorphic_args(&self) -> bool {
 
        use ParserTypeVariant::*;
 
        match self {
 
            Message | Bool | Byte | Short | Int | Long | String | IntegerLiteral | Inferred => false,
 
            _ => true
 
        }
 
    }
 
}
 

	
 
/// 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, serde::Serialize, serde::Deserialize)]
 
pub struct ParserType {
 
    pub this: ParserTypeId,
 
    pub pos: InputPosition,
 
    pub variant: ParserTypeVariant,
 
}
 

	
 
/// 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, serde::Serialize, serde::Deserialize)]
 
pub struct SymbolicParserType {
 
    // Phase 1: parser
 
    pub identifier: NamespacedIdentifier,
 
    /// The user-specified polymorphic arguments. Zero-length implies that the
 
    /// user did not specify any of them, and they're either not needed or all
 
    /// need to be inferred. Otherwise the number of polymorphic arguments must
 
    /// match those of the corresponding definition
 
    pub poly_args: Vec<ParserTypeId>,
 
    // Phase 2: validation/linking (for types in function/component bodies) and
 
    //  type table construction (for embedded types of structs/unions)
 
    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, serde::Serialize, serde::Deserialize)]
 
pub enum SymbolicParserTypeVariant {
 
    Definition(DefinitionId),
 
    PolyArg(usize), // index of polyarg in the definition
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 
pub enum PrimitiveType {
 
    Input,
 
    Output,
 
    Message,
 
    Boolean,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    Symbolic(PrimitiveSymbolic)
 
}
 

	
 
// TODO: @cleanup, remove PartialEq implementations
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct PrimitiveSymbolic {
 
    // Phase 1: parser
 
    pub(crate) identifier: NamespacedIdentifier,
 
    // Phase 2: typing
 
    pub(crate) definition: Option<DefinitionId>
 
}
 

	
 
impl PartialEq for PrimitiveSymbolic {
 
    fn eq(&self, other: &Self) -> bool {
 
        self.identifier == other.identifier
 
    }
 
}
 
impl Eq for PrimitiveSymbolic{}
 

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

	
 
#[allow(dead_code)]
 
impl Type {
 
    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::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")?;
 
            }
 
            PrimitiveType::Symbolic(data) => {
 
                // Type data is in ASCII range.
 
                if let Some(id) = &data.definition {
 
                    write!(
 
                        f, "Symbolic({}, id: {})", 
 
                        String::from_utf8_lossy(&data.identifier.value),
 
                        id.index
 
                    )?;
 
                } else {
 
                    write!(
 
                        f, "Symbolic({}, id: Unresolved)",
 
                        String::from_utf8_lossy(&data.identifier.value)
 
                    )?;
 
                }
 
            }
 
        }
 
        if self.array {
 
            write!(f, "[]")
 
        } else {
 
            Ok(())
 
        }
 
    }
 
}
 

	
 
type CharacterData = Vec<u8>;
 
type IntegerData = i64;
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub enum Constant {
 
    Null, // message
 
    True,
 
    False,
 
    Character(CharacterData),
 
    Integer(IntegerData),
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub enum Method {
 
    Get,
 
    Fires,
 
    Create,
 
    Symbolic(MethodSymbolic)
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct MethodSymbolic {
 
    pub(crate) identifier: NamespacedIdentifier,
 
    pub(crate) definition: Option<DefinitionId>
 
}
 

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

	
 
#[derive(Debug, Clone, Copy, serde::Serialize, serde::Deserialize)]
 
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")
 
        }
 
    }
 
}
 

	
 
pub trait VariableScope {
 
    fn parent_scope(&self, h: &Heap) -> Option<Scope>;
 
    fn get_variable(&self, h: &Heap, id: &Identifier) -> Option<VariableId>;
 
}
 

	
 
impl VariableScope for Scope {
 
    fn parent_scope(&self, h: &Heap) -> Option<Scope> {
 
        match self {
 
            Scope::Definition(def) => h[*def].parent_scope(h),
 
            Scope::Regular(stmt) => h[*stmt].parent_scope(h),
 
            Scope::Synchronous((stmt, _)) => h[*stmt].parent_scope(h),
 
        }
 
    }
 
    fn get_variable(&self, h: &Heap, id: &Identifier) -> Option<VariableId> {
 
        match self {
 
            Scope::Definition(def) => h[*def].get_variable(h, id),
 
            Scope::Regular(stmt) => h[*stmt].get_variable(h, id),
 
            Scope::Synchronous((stmt, _)) => h[*stmt].get_variable(h, id),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
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'"),
 
        }
 
    }
 
}
 

	
 
impl SyntaxElement for Variable {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            Variable::Parameter(decl) => decl.position(),
 
            Variable::Local(decl) => decl.position(),
 
        }
 
    }
 
}
 

	
 
/// TODO: Remove distinction between parameter/local and add an enum to indicate
 
///     the distinction between the two
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct Parameter {
 
    pub this: ParameterId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub parser_type: ParserTypeId,
 
    pub identifier: Identifier,
 
}
 

	
 
impl SyntaxElement for Parameter {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct Local {
 
    pub this: LocalId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub parser_type: ParserTypeId,
 
    pub identifier: Identifier,
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
}
 
impl SyntaxElement for Local {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub enum Definition {
 
    Struct(StructDefinition),
 
    Enum(EnumDefinition),
 
    Component(Component),
 
    Function(Function),
 
}
 

	
 
impl Definition {
 
    pub fn is_struct(&self) -> bool {
 
        match self {
 
            Definition::Struct(_) => true,
 
            _ => false
 
        }
 
    }
 
    pub fn as_struct(&self) -> &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 fn as_enum(&self) -> &EnumDefinition {
 
        match self {
 
            Definition::Enum(result) => result,
 
            _ => panic!("Unable to cast 'Definition' to 'EnumDefinition'"),
 
        }
 
    }
 
    pub fn is_component(&self) -> bool {
 
        match self {
 
            Definition::Component(_) => true,
 
            _ => false,
 
        }
 
    }
 
    pub fn as_component(&self) -> &Component {
 
        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 fn as_function(&self) -> &Function {
 
        match self {
 
            Definition::Function(result) => result,
 
            _ => panic!("Unable to cast `Definition` to `Function`"),
 
        }
 
    }
 
    pub fn identifier(&self) -> &Identifier {
 
        match self {
 
            Definition::Struct(def) => &def.identifier,
 
            Definition::Enum(def) => &def.identifier,
 
            Definition::Component(com) => &com.identifier,
 
            Definition::Function(fun) => &fun.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
 
        match self {
 
            Definition::Component(com) => com.body,
 
            Definition::Function(fun) => fun.body,
 
            _ => panic!("cannot retrieve body (for EnumDefinition or StructDefinition)")
 
        }
 
    }
 
}
 

	
 
impl SyntaxElement for Definition {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            Definition::Struct(def) => def.position,
 
            Definition::Enum(def) => def.position,
 
            Definition::Component(def) => def.position(),
 
            Definition::Function(def) => def.position(),
 
        }
 
    }
 
}
 

	
 
impl VariableScope for Definition {
 
    fn parent_scope(&self, _h: &Heap) -> Option<Scope> {
 
        None
 
    }
 
    fn get_variable(&self, h: &Heap, id: &Identifier) -> Option<VariableId> {
 
        for &parameter_id in self.parameters().iter() {
 
            let parameter = &h[parameter_id];
 
            if parameter.identifier.value == id.value {
 
                return Some(parameter_id.0);
 
            }
 
        }
 
        None
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct StructFieldDefinition {
 
    pub position: InputPosition,
 
    pub field: Identifier,
 
    pub parser_type: ParserTypeId,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct StructDefinition {
 
    pub this: StructId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    pub fields: Vec<StructFieldDefinition>
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize, PartialEq)]
 
pub enum EnumVariantValue {
 
    None,
 
    Integer(i64),
 
    Type(ParserTypeId),
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct EnumVariantDefinition {
 
    pub position: InputPosition,
 
    pub identifier: Identifier,
 
    pub value: EnumVariantValue,
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct EnumDefinition {
 
    pub this: EnumId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    pub variants: Vec<EnumVariantDefinition>,
 
}
 

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

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct Component {
 
    pub this: ComponentId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub variant: ComponentVariant,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    pub parameters: Vec<ParameterId>,
 
    pub body: StatementId,
 
}
 

	
 
impl SyntaxElement for Component {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct Function {
 
    pub this: FunctionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub return_type: ParserTypeId,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    pub parameters: Vec<ParameterId>,
 
    pub body: StatementId,
 
}
 

	
 
impl SyntaxElement for Function {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
impl Statement {
 
    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_assert(&self) -> &AssertStatement {
 
        match self {
 
            Statement::Assert(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `AssertStatement`"),
 
        }
 
    }
 
    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_put(&self) -> &PutStatement {
 
        match self {
 
            Statement::Put(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `PutStatement`"),
 
        }
 
    }
 
    pub fn as_expression(&self) -> &ExpressionStatement {
 
        match self {
 
            Statement::Expression(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `ExpressionStatement`"),
 
        }
 
    }
 
    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::Skip(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::Assert(stmt) => stmt.next = Some(next),
 
            Statement::New(stmt) => stmt.next = Some(next),
 
            Statement::Put(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!(),
 
        }
 
    }
 
}
 

	
 
impl SyntaxElement for Statement {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            Statement::Block(stmt) => stmt.position(),
 
            Statement::Local(stmt) => stmt.position(),
 
            Statement::Skip(stmt) => stmt.position(),
 
            Statement::Labeled(stmt) => stmt.position(),
 
            Statement::If(stmt) => stmt.position(),
 
            Statement::EndIf(stmt) => stmt.position(),
 
            Statement::While(stmt) => stmt.position(),
 
            Statement::EndWhile(stmt) => stmt.position(),
 
            Statement::Break(stmt) => stmt.position(),
 
            Statement::Continue(stmt) => stmt.position(),
 
            Statement::Synchronous(stmt) => stmt.position(),
 
            Statement::EndSynchronous(stmt) => stmt.position(),
 
            Statement::Return(stmt) => stmt.position(),
 
            Statement::Assert(stmt) => stmt.position(),
 
            Statement::Goto(stmt) => stmt.position(),
 
            Statement::New(stmt) => stmt.position(),
 
            Statement::Put(stmt) => stmt.position(),
 
            Statement::Expression(stmt) => stmt.position(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct BlockStatement {
 
    pub this: BlockStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    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()
 
    }
 
}
 

	
 
impl SyntaxElement for BlockStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
impl VariableScope for BlockStatement {
 
    fn parent_scope(&self, _h: &Heap) -> Option<Scope> {
 
        self.parent_scope.clone()
 
    }
 
    fn get_variable(&self, h: &Heap, id: &Identifier) -> Option<VariableId> {
 
        for local_id in self.locals.iter() {
 
            let local = &h[*local_id];
 
            if local.identifier.value == id.value {
 
                return Some(local_id.0);
 
            }
 
        }
 
        None
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
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 next(&self) -> Option<StatementId> {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.next,
 
            LocalStatement::Channel(stmt) => stmt.next,
 
        }
 
    }
 
}
 

	
 
impl SyntaxElement for LocalStatement {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            LocalStatement::Memory(stmt) => stmt.position(),
 
            LocalStatement::Channel(stmt) => stmt.position(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct MemoryStatement {
 
    pub this: MemoryStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub variable: LocalId,
 
    pub initial: ExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for MemoryStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
/// 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, serde::Serialize, serde::Deserialize)]
 
pub struct ChannelStatement {
 
    pub this: ChannelStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub from: LocalId, // output
 
    pub to: LocalId,   // input
 
    // Phase 2: linker
 
    pub relative_pos_in_block: u32,
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for ChannelStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct SkipStatement {
 
    pub this: SkipStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for SkipStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
impl SyntaxElement for LabeledStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct IfStatement {
 
    pub this: IfStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub test: ExpressionId,
 
    pub true_body: StatementId,
 
    pub false_body: StatementId,
 
    // Phase 2: linker
 
    pub end_if: Option<EndIfStatementId>,
 
}
 

	
 
impl SyntaxElement for IfStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
impl SyntaxElement for EndIfStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct WhileStatement {
 
    pub this: WhileStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub test: ExpressionId,
 
    pub body: StatementId,
 
    // Phase 2: linker
 
    pub end_while: Option<EndWhileStatementId>,
 
    pub in_sync: Option<SynchronousStatementId>,
 
}
 

	
 
impl SyntaxElement for WhileStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
impl SyntaxElement for EndWhileStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct BreakStatement {
 
    pub this: BreakStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<EndWhileStatementId>,
 
}
 

	
 
impl SyntaxElement for BreakStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ContinueStatement {
 
    pub this: ContinueStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub label: Option<Identifier>,
 
    // Phase 2: linker
 
    pub target: Option<WhileStatementId>,
 
}
 

	
 
impl SyntaxElement for ContinueStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct SynchronousStatement {
 
    pub this: SynchronousStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    // pub parameters: Vec<ParameterId>,
 
    pub body: StatementId,
 
    // Phase 2: linker
 
    pub end_sync: Option<EndSynchronousStatementId>,
 
    pub parent_scope: Option<Scope>,
 
}
 

	
 
impl SyntaxElement for SynchronousStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
impl VariableScope for SynchronousStatement {
 
    fn parent_scope(&self, _h: &Heap) -> Option<Scope> {
 
        self.parent_scope.clone()
 
    }
 
    fn get_variable(&self, _h: &Heap, _id: &Identifier) -> Option<VariableId> {
 
        // TODO: Another case of "where was this used for?"
 
        // for parameter_id in self.parameters.iter() {
 
        //     let parameter = &h[*parameter_id];
 
        //     if parameter.identifier.value == id.value {
 
        //         return Some(parameter_id.0);
 
        //     }
 
        // }
 
        None
 
    }
 
}
 

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

	
 
impl SyntaxElement for EndSynchronousStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ReturnStatement {
 
    pub this: ReturnStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub expression: ExpressionId,
 
}
 

	
 
impl SyntaxElement for ReturnStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct AssertStatement {
 
    pub this: AssertStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for AssertStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct GotoStatement {
 
    pub this: GotoStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub label: Identifier,
 
    // Phase 2: linker
 
    pub target: Option<LabeledStatementId>,
 
}
 

	
 
impl SyntaxElement for GotoStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct NewStatement {
 
    pub this: NewStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub expression: CallExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for NewStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct PutStatement {
 
    pub this: PutStatementId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub port: ExpressionId,
 
    pub message: ExpressionId,
 
    // Phase 2: linker
 
    pub next: Option<StatementId>,
 
}
 

	
 
impl SyntaxElement for PutStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
impl SyntaxElement for ExpressionStatement {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub enum Expression {
 
    Assignment(AssignmentExpression),
 
    Conditional(ConditionalExpression),
 
    Binary(BinaryExpression),
 
    Unary(UnaryExpression),
 
    Indexing(IndexingExpression),
 
    Slicing(SlicingExpression),
 
    Select(SelectExpression),
 
    Array(ArrayExpression),
 
    Constant(ConstantExpression),
 
    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) -> &ConstantExpression {
 
        match self {
 
            Expression::Constant(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::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::Constant(expr) => &expr.parent,
 
            Expression::Call(expr) => &expr.parent,
 
            Expression::Variable(expr) => &expr.parent,
 
        }
 
    }
 
    pub fn set_parent(&mut self, parent: ExpressionParent) {
 
        match self {
 
            Expression::Assignment(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::Constant(expr) => expr.parent = parent,
 
            Expression::Call(expr) => expr.parent = parent,
 
            Expression::Variable(expr) => expr.parent = parent,
 
        }
 
    }
 
}
 

	
 
impl SyntaxElement for Expression {
 
    fn position(&self) -> InputPosition {
 
        match self {
 
            Expression::Assignment(expr) => expr.position(),
 
            Expression::Conditional(expr) => expr.position(),
 
            Expression::Binary(expr) => expr.position(),
 
            Expression::Unary(expr) => expr.position(),
 
            Expression::Indexing(expr) => expr.position(),
 
            Expression::Slicing(expr) => expr.position(),
 
            Expression::Select(expr) => expr.position(),
 
            Expression::Array(expr) => expr.position(),
 
            Expression::Constant(expr) => expr.position(),
 
            Expression::Call(expr) => expr.position(),
 
            Expression::Variable(expr) => expr.position(),
 
        }
 
    }
 
}
 

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

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct AssignmentExpression {
 
    pub this: AssignmentExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub left: ExpressionId,
 
    pub operation: AssignmentOperator,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for AssignmentExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ConditionalExpression {
 
    pub this: ConditionalExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for ConditionalExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 
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, serde::Serialize, serde::Deserialize)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for BinaryExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

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

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub operation: UnaryOperation,
 
    pub expression: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for UnaryExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for IndexingExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for SlicingExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub subject: ExpressionId,
 
    pub field: Field,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for SelectExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ArrayExpression {
 
    pub this: ArrayExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub elements: Vec<ExpressionId>,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for ArrayExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for CallExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct ConstantExpression {
 
    pub this: ConstantExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub value: Constant,
 
    // Phase 2: linker
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for ConstantExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
 

	
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub struct VariableExpression {
 
    pub this: VariableExpressionId,
 
    // Phase 1: parser
 
    pub position: InputPosition,
 
    pub identifier: NamespacedIdentifier,
 
    // Phase 2: linker
 
    pub declaration: Option<VariableId>,
 
    pub parent: ExpressionParent,
 
}
 

	
 
impl SyntaxElement for VariableExpression {
 
    fn position(&self) -> InputPosition {
 
        self.position
 
    }
 
}
src/protocol/parser/type_resolver.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::type_table::{ConcreteType, ConcreteTypeVariant};
 
use crate::protocol::inputsource::*;
 
use super::type_table::*;
 
use super::symbol_table::*;
 
use super::visitor::{
 
    STMT_BUFFER_INIT_CAPACITY,
 
    EXPR_BUFFER_INIT_CAPACITY,
 
    Ctx,
 
    Visitor2,
 
    VisitorResult
 
};
 
use std::collections::HashMap;
 

	
 
enum ExprType {
 
    Regular, // expression statement or return statement
 
    Memory, // memory statement's expression
 
    Condition, // if/while conditional statement
 
    Assert, // assert statement
 
pub(crate) enum InferredPart {
 
    // Unknown section of inferred type, yet to be inferred
 
    Unknown,
 
    // No subtypes
 
    Message,
 
    Bool,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    String,
 
    // One subtype
 
    Array,
 
    Slice,
 
    Input,
 
    Output,
 
    // One or more subtypes
 
    Instance(DefinitionId, usize),
 
}
 

	
 
impl From<ConcreteTypeVariant> for InferredPart {
 
    fn from(v: ConcreteTypeVariant) -> Self {
 
        use ConcreteTypeVariant as CTV;
 
        use InferredPart as IP;
 

	
 
        match v {
 
            CTV::Message => IP::Message,
 
            CTV::Bool => IP::Bool,
 
            CTV::Byte => IP::Byte,
 
            CTV::Short => IP::Short,
 
            CTV::Int => IP::Int,
 
            CTV::Long => IP::Long,
 
            CTV::String => IP::String,
 
            CTV::Array => IP::Array,
 
            CTV::Slice => IP::Slice,
 
            CTV::Input => IP::Input,
 
            CTV::Output => IP::Output,
 
            CTV::Instance(definition_id, num_sub) => IP::Instance(definition_id, num_sub),
 
        }
 
    }
 
}
 

	
 
pub(crate) struct InferenceType {
 
    origin: ParserTypeId,
 
    inferred: Vec<InferredPart>,
 
}
 

	
 
impl InferenceType {
 
    fn new(inferred_type: ParserTypeId) -> Self {
 
        Self{ origin: inferred_type, inferred: vec![InferredPart::Unknown] }
 
    }
 

	
 
    fn assign_concrete(&mut self, concrete_type: &ConcreteType) {
 
        self.inferred.clear();
 
        self.inferred.reserve(concrete_type.v.len());
 
        for variant in concrete_type.v {
 
            self.inferred.push(InferredPart::from(variant))
 
        }
 
    }
 
}
 

	
 
// TODO: @cleanup I will do a very dirty implementation first, because I have no idea
 
//  what I am doing.
 
// Very rough idea:
 
//  - go through entire AST first, find all places where we have inferred types
 
//      (which may be embedded) and store them in some kind of map.
 
//  - go through entire AST and visit all expressions depth-first. We will
 
//      attempt to resolve the return type of each expression. If we can't then
 
//      we store them in another lookup map and link the dependency on an
 
//      inferred variable to that expression.
 
//  - keep iterating until we have completely resolved all variables.
 

	
 
/// This particular visitor will recurse depth-first into the AST and ensures
 
/// that all expressions have the appropriate types. At the moment this implies:
 
///
 
///     - Type checking arguments to unary and binary operators.
 
///     - Type checking assignment, indexing, slicing and select expressions.
 
///     - Checking arguments to functions and component instantiations.
 
///
 
/// This will be achieved by slowly descending into the AST. At any given
 
/// expression we may depend on
 
pub(crate) struct TypeResolvingVisitor {
 
    // Tracking traversal state
 
    expr_type: ExprType,
 

	
 
    // Buffers for iteration over substatements and subexpressions
 
    stmt_buffer: Vec<StatementId>,
 
    expr_buffer: Vec<ExpressionId>,
 

	
 
    // Map for associating "auto"/"polyarg" variables with a concrete type where
 
    // it is not yet determined.
 
    env: HashMap<ParserTypeId, ConcreteTypeVariant>
 
    // If instantiating a monomorph of a polymorphic proctype, then we store the
 
    // values of the polymorphic values here.
 
    polyvars: Vec<(Identifier, ConcreteTypeVariant)>,
 
    // Mapping from parser type to inferred type. We attempt to continue to
 
    // specify these types until we're stuck or we've fully determined the type.
 
    infer_types: HashMap<ParserTypeId, InferenceType>,
 
    // Mapping from variable ID to parser type, optionally inferred, so then
 
    var_types: HashMap<VariableId, ParserTypeId>,
 
}
 

	
 
impl TypeResolvingVisitor {
 
    pub(crate) fn new() -> Self {
 
        TypeResolvingVisitor{
 
            expr_type: ExprType::Regular,
 
            stmt_buffer: Vec::with_capacity(STMT_BUFFER_INIT_CAPACITY),
 
            expr_buffer: Vec::with_capacity(EXPR_BUFFER_INIT_CAPACITY),
 
            env: HashMap::new(),
 
            infer_types: HashMap::new(),
 
            var_types: HashMap::new(),
 
        }
 
    }
 

	
 
    fn reset(&mut self) {
 
        self.expr_type = ExprType::Regular;
 
        self.stmt_buffer.clear();
 
        self.expr_buffer.clear();
 
        self.infer_types.clear();
 
        self.var_types.clear();
 
    }
 
}
 

	
 
impl Visitor2 for TypeResolvingVisitor {
 
    // Definitions
 

	
 
    fn visit_component_definition(&mut self, ctx: &mut Ctx, id: ComponentId) -> VisitorResult {
 
        self.reset();
 
        let comp_def = &ctx.heap[id];
 
        for param_id in comp_def.parameters.clone() {
 
            let param = &ctx.heap[param_id];
 
            self.var_types.insert(param_id.upcast(), param.parser_type);
 
        }
 

	
 
        let body_stmt_id = ctx.heap[id].body;
 
        self.visit_stmt(ctx, body_stmt_id)
 
    }
 

	
 
    fn visit_function_definition(&mut self, ctx: &mut Ctx, id: FunctionId) -> VisitorResult {
 
        self.reset();
 
        let func_def = &ctx.heap[id];
 
        for param_id in func_def.parameters.clone() {
 
            let param = &ctx.heap[param_id];
 
            self.var_types.insert(param_id.upcast(), param.parser_type);
 
        }
 
        let body_stmt_id = ctx.heap[id].body;
 

	
 

	
 
        self.visit_stmt(ctx, body_stmt_id)
 
    }
 

	
 
    // Statements
 

	
 
    fn visit_block_stmt(&mut self, ctx: &mut Ctx, id: BlockStatementId) -> VisitorResult {
 
        // Transfer statements for traversal
 
        let block = &ctx.heap[id];
 

	
 
        let old_len_stmts = self.stmt_buffer.len();
 
        self.stmt_buffer.extend(&block.statements);
 
        let new_len_stmts = self.stmt_buffer.len();
 

	
 
        // Traverse statements
 
        for stmt_idx in old_len_stmts..new_len_stmts {
 
            let stmt_id = self.stmt_buffer[stmt_idx];
 
            self.expr_type = ExprType::Regular;
 
            self.visit_stmt(ctx, stmt_id)?;
 
        for stmt_id in block.statements.clone() {
 
            self.visit_stmt(ctx, stmt_id);
 
        }
 

	
 
        self.stmt_buffer.truncate(old_len_stmts);
 
        Ok(())
 
    }
 

	
 
    fn visit_local_memory_stmt(&mut self, ctx: &mut Ctx, id: MemoryStatementId) -> VisitorResult {
 
        let memory_stmt = &ctx.heap[id];
 

	
 

	
 
        let local = &ctx.heap[memory_stmt.variable];
 
        self.var_types.insert(memory_stmt.variable, )
 

	
 
        Ok(())
 
    }
 

	
 
    fn visit_local_channel_stmt(&mut self, ctx: &mut Ctx, id: ChannelStatementId) -> VisitorResult {
 
        Ok(())
 
    }
 
}
 

	
 
impl TypeResolvingVisitor {
 
    /// Checks if the `ParserType` contains any inferred variables. If so then
 
    /// they will be inserted into the `infer_types` variable. Here we assume
 
    /// we're parsing the body of a proctype, so any reference to polymorphic
 
    /// variables must refer to the polymorphic arguments of the proctype's
 
    /// definition.
 
    /// TODO: @cleanup: The symbol_table -> type_table pattern appears quite
 
    ///     a lot, will likely need to create some kind of function for this
 
    fn insert_parser_type_if_needs_inference(
 
        &mut self, ctx: &mut Ctx, root_id: RootId, parser_type_id: ParserTypeId
 
    ) -> Result<(), ParseError2> {
 
        use ParserTypeVariant as PTV;
 

	
 
        let mut to_consider = vec![parser_type_id];
 
        while !to_consider.is_empty() {
 
            let parser_type_id = to_consider.pop().unwrap();
 
            let parser_type = &mut ctx.heap[parser_type_id];
 

	
 
            match &mut parser_type.variant {
 
                PTV::Inferred => {
 
                    self.env.insert(parser_type_id, InferenceType::new(parser_type_id));
 
                },
 
                PTV::Array(subtype_id) => { to_consider.push(*subtype_id); },
 
                PTV::Input(subtype_id) => { to_consider.push(*subtype_id); },
 
                PTV::Output(subtype_id) => { to_consider.push(*subtype_id); },
 
                PTV::Symbolic(symbolic) => {
 
                    // If not yet resolved, try to resolve
 
                    if symbolic.variant.is_none() {
 
                        let mut found = false;
 
                        for (poly_idx, (poly_var, _)) in self.polyvars.iter().enumerate() {
 
                            if symbolic.identifier.value == poly_var.value {
 
                                // Found a match
 
                                symbolic.variant = Some(SymbolicParserTypeVariant::PolyArg(poly_idx))
 
                                found = true;
 
                                break;
 
                            }
 
                        }
 

	
 
                        if !found {
 
                            // Attempt to find in symbol/type table
 
                            let symbol = ctx.symbols.resolve_namespaced_symbol(root_id, &symbolic.identifier);
 
                            if symbol.is_none() {
 
                                let module_source = &ctx.module.source;
 
                                return Err(ParseError2::new_error(
 
                                    module_source, symbolic.identifier.position,
 
                                    "Could not resolve symbol to a type"
 
                                ));
 
                            }
 

	
 
                            // Check if symbol was fully resolved
 
                            let (symbol, ident_iter) = symbol.unwrap();
 
                            if ident_iter.num_remaining() != 0 {
 
                                let module_source = &ctx.module.source;
 
                                ident_iter.
 
                                return Err(ParseError2::new_error(
 
                                    module_source, symbolic.identifier.position,
 
                                    "Could not resolve symbol to a type"
 
                                ).with_postfixed_info(
 
                                    module_source, symbol.position,
 
                                    "Could resolve part of the identifier to this symbol"
 
                                ));
 
                            }
 

	
 
                            // Check if symbol resolves to struct/enum
 
                            let definition_id = match symbol.symbol {
 
                                Symbol::Namespace(_) => {
 
                                    let module_source = &ctx.module.source;
 
                                    return Err(ParseError2::new_error(
 
                                        module_source, symbolic.identifier.position,
 
                                        "Symbol resolved to a module instead of a type"
 
                                    ));
 
                                },
 
                                Symbol::Definition((_, definition_id)) => definition_id
 
                            };
 

	
 
                            // Retrieve from type table and make sure it is a
 
                            // reference to a struct/enum/union
 
                            // TODO: @types Allow function pointers
 
                            let def_type = ctx.types.get_base_definition(&definition_id);
 
                            debug_assert!(def_type.is_some(), "Expected to resolve definition ID to type definition in type table");
 
                            let def_type = def_type.unwrap();
 

	
 
                            let def_type_class = def_type.definition.type_class();
 
                            if !def_type_class.is_data_type() {
 
                                return Err(ParseError2::new_error(
 
                                    &ctx.module.source, symbolic.identifier.position,
 
                                    &format!("Symbol refers to a {}, only data types are supported", def_type_class)
 
                                ));
 
                            }
 

	
 
                            // Now that we're certain it is a datatype, make
 
                            // sure that the number of polyargs in the symbolic
 
                            // type matches that of the definition, or conclude
 
                            // that all polyargs need to be inferred.
 
                            if symbolic.poly_args.len() != def_type.poly_args.len() {
 
                                if symbolic.poly_args.is_empty() {
 
                                    // Modify ParserType to have auto-inferred
 
                                    // polymorphic arguments
 
                                    symbolic.poly_args.
 
                                }
 
                            }
 
                        }
 
                    }
 
                },
 
                _ => {} // Builtin, doesn't require inference
 
            }
 
        }
 
    }
 
}
 
\ 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::*;
 

	
 
//------------------------------------------------------------------------------
 
// 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 => "enum",
 
            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_definition: DefinitionId,
 
    pub(crate) definition: DefinedTypeVariant,
 
    pub(crate) poly_args: Vec<PolyArg>,
 
    pub(crate) is_polymorph: bool,
 
    pub(crate) is_pointerlike: bool,
 
    pub(crate) monomorphs: Vec<u32>, // TODO: ?
 
}
 

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

	
 
pub struct PolyArg {
 
    identifier: Identifier,
 
    /// Whether the polymorphic argument 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
 
        }
 
    }
 
}
 

	
 
/// `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 {
 
    variants: Vec<EnumVariant>,
 
    representation: PrimitiveType,
 
}
 

	
 
// TODO: Also support maximum u64 value
 
pub struct EnumVariant {
 
    identifier: Identifier,
 
    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 {
 
    variants: Vec<UnionVariant>,
 
    tag_representation: PrimitiveType
 
}
 

	
 
pub struct UnionVariant {
 
    identifier: Identifier,
 
    parser_type: Option<ParserTypeId>,
 
    tag_value: i64,
 
}
 

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

	
 
pub struct StructField {
 
    identifier: Identifier,
 
    parser_type: ParserTypeId,
 
}
 

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

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

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

	
 
//------------------------------------------------------------------------------
 
// 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();
 
    }
 
}
 

	
 
#[derive(Copy, Clone)]
 
pub(crate) enum ConcreteTypeVariant {
 
    // No subtypes
 
    Message,
 
    Bool,
 
    Byte,
 
    Short,
 
    Int,
 
    Long,
 
    String,
 
    // One subtype
 
    Array,
 
    Slice,
 
    Input,
 
    Output,
 
    // Multiple subtypes (definition of thing and number of poly args)
 
    Instance(DefinitionId, usize)
 
}
 

	
 
pub(crate) struct ConcreteType {
 
    // serialized version (interpret as serialized depth-first tree, with
 
    // variant indicating the number of children (subtypes))
 
    pub(crate) v: Vec<ConcreteTypeVariant>
 
}
 

	
 
/// 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),
 
    /// ParserType points to a user-defined type that is already resolved in the
 
    /// type table.
 
    Resolved((RootId, DefinitionId)),
 
    /// ParserType points to a user-defined type that is not yet resolved into
 
    /// the type table.
 
    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]
 
}
 

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

	
 
impl TypeTable {
 
    /// Construct a new type table without any resolved types. Types will be
 
    /// resolved on-demand.
 
    pub(crate) fn new(ctx: &mut TypeCtx) -> Result<Self, ParseError2> {
 
        // Make sure we're allowed to cast root_id to index into ctx.modules
 
        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();
 
        let mut table = Self{
 
            lookup: HashMap::with_capacity(reserve_size),
 
            iter: TypeIterator::new(),
 
            parser_type_iter: VecDeque::with_capacity(64),
 
        };
 

	
 
        // 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];
 
                table.resolve_base_definition(ctx, definition_id)?;
 
            }
 
        }
 

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

	
 
        Ok(table)
 
    }
 

	
 
    /// 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)
 
    }
 

	
 
    /// 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<(), ParseError2> {
 
        // 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::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, ParseError2> {
 
        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();
 

	
 
        // Check if the enum should be implemented as a classic enumeration or
 
        // a tagged union. Keep track of variant index for error messages. Make
 
        // sure all embedded types are resolved.
 
        let mut first_tag_value = None;
 
        let mut first_int_value = None;
 
        for variant in &definition.variants {
 
            match &variant.value {
 
                EnumVariantValue::None => {},
 
                EnumVariantValue::Integer(_) => if first_int_value.is_none() {
 
                    first_int_value = Some(variant.position);
 
                },
 
                EnumVariantValue::Type(variant_type_id) => {
 
                    if first_tag_value.is_none() {
 
                        first_tag_value = Some(variant.position);
 
                    }
 

	
 
                    // Check if the embedded type needs to be resolved
 
                    let resolve_result = self.resolve_base_parser_type(ctx, &definition.poly_vars, root_id, *variant_type_id)?;
 
                    if !self.ingest_resolve_result(ctx, resolve_result)? {
 
                        return Ok(false)
 
                    }
 
                }
 
            }
 
        }
 

	
 
        if first_tag_value.is_some() && first_int_value.is_some() {
 
            // Not illegal, but useless and probably a programmer mistake
 
            let module_source = &ctx.modules[root_id.index as usize].source;
 
            let tag_pos = first_tag_value.unwrap();
 
            let int_pos = first_int_value.unwrap();
 
            return Err(
 
                ParseError2::new_error(
 
                    module_source, definition.position,
 
                    "Illegal combination of enum integer variant(s) and enum union variant(s)"
 
                )
 
                    .with_postfixed_info(module_source, int_pos, "Assigning an integer value here")
 
                    .with_postfixed_info(module_source, tag_pos, "Embedding a type in a union variant here")
 
            );
 
        }
 

	
 
        // Enumeration is legal
 
        if first_tag_value.is_some() {
 
            // Implement as a tagged union
 

	
 
            // 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 parser_type = match &variant.value {
 
                    EnumVariantValue::None => {
 
                        None
 
                    },
 
                    EnumVariantValue::Type(parser_type_id) => {
 
                        // Type should be resolvable, we checked this above
 
                        Some(*parser_type_id)
 
                    },
 
                    EnumVariantValue::Integer(_) => {
 
                        debug_assert!(false, "Encountered `Integer` variant after asserting enum is a discriminated union");
 
                        unreachable!();
 
                    }
 
                };
 

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

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

	
 
            let mut poly_args = self.create_initial_poly_args(&definition.poly_vars);
 
            for variant in &variants {
 
                if let Some(embedded) = variant.parser_type {
 
                    self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, &mut poly_args, root_id, embedded)?;
 
                }
 
            }
 
            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_definition: definition_id,
 
                definition: DefinedTypeVariant::Union(UnionType{
 
                    variants,
 
                    tag_representation: Self::enum_tag_type(-1, tag_value),
 
                }),
 
                poly_args,
 
                is_polymorph,
 
                is_pointerlike: false, // TODO: @cyclic_types
 
                monomorphs: Vec::new()
 
            });
 
        } else {
 
            // Implement as a regular 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,
 
                        });
 
                    },
 
                    EnumVariantValue::Type(_) => {
 
                        debug_assert!(false, "Encountered `Type` variant after asserting enum is not a discriminated union");
 
                        unreachable!();
 
                    }
 
                }
 
                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"
 
            )?;
 
            self.check_poly_args_collision(ctx, root_id, &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_definition: definition_id,
 
                definition: DefinedTypeVariant::Enum(EnumType{
 
                    variants,
 
                    representation: Self::enum_tag_type(min_enum_value, max_enum_value)
 
                }),
 
                poly_args: self.create_initial_poly_args(&definition.poly_vars),
 
                is_polymorph: false,
 
                is_pointerlike: false,
 
                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, ParseError2> {
 
        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)?;
 
            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,
 
            })
 
        }
 

	
 
        // 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_args(&definition.poly_vars);
 
        for field in &fields {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, &mut poly_args, root_id, field.parser_type)?;
 
        }
 

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

	
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Struct(StructType{
 
                fields,
 
            }),
 
            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, ParseError2> {
 
        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
 
        )?;
 
        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
 
            )?;
 
            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,
 
            })
 
        }
 

	
 
        // 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_args(&definition.poly_vars);
 
        self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, &mut poly_args, root_id, definition.return_type)?;
 
        for argument in &arguments {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, &mut poly_args, root_id, 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_definition: definition_id,
 
            definition: DefinedTypeVariant::Function(FunctionType{
 
                return_type,
 
                arguments,
 
            }),
 
            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, ParseError2> {
 
        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
 
            )?;
 
            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
 
            })
 
        }
 

	
 
        // 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_args(&definition.poly_vars);
 
        for argument in &arguments {
 
            self.check_and_resolve_embedded_type_and_modify_poly_args(ctx, &mut poly_args, root_id, argument.parser_type)?;
 
        }
 

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

	
 
        // Construct entry in type table
 
        self.lookup.insert(definition_id, DefinedType{
 
            ast_definition: definition_id,
 
            definition: DefinedTypeVariant::Component(ComponentType{
 
                variant: component_variant,
 
                arguments,
 
            }),
 
            poly_args,
 
            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, ParseError2> {
 
        match result {
 
            ResolveResult::BuiltIn | ResolveResult::PolyArg(_) => 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 = ParseError2::new_error(
 
                        &ctx.modules[root_id.index as usize].source, ctx.heap[definition_id].position(),
 
                        "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
 
                        );
 
                    }
 

	
 
                    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.
 
    ///
 
    /// 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, ParseError2> {
 
        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
 
        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);
 
                },
 
                // 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!();
 
                },
 
                // 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 poly_arg.value == symbolic.identifier.value {
 
                            set_resolve_result(ResolveResult::PolyArg(poly_arg_idx));
 
                            continue 'resolve_loop;
 
                        }
 
                    }
 

	
 
                    // Lookup the definition in the symbol table
 
                    let symbol = ctx.symbols.resolve_namespaced_symbol(root_id, &symbolic.identifier);
 
                    if symbol.is_none() {
 
                        return Err(ParseError2::new_error(
 
                            &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                            "Could not resolve type"
 
                        ))
 
                    }
 

	
 
                    let (symbol_value, mut ident_iter) = symbol.unwrap();
 
                    match symbol_value.symbol {
 
                        Symbol::Namespace(_) => {
 
                            // Reference to a namespace instead of a type
 
                            return if ident_iter.num_remaining() == 0 {
 
                                Err(ParseError2::new_error(
 
                                    &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                                    "Expected a type, got a module name"
 
                                ))
 
                            } else {
 
                                let next_identifier = ident_iter.next().unwrap();
 
                                Err(ParseError2::new_error(
 
                                    &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                                    &format!("Could not find symbol '{}' with this module", String::from_utf8_lossy(next_identifier))
 
                                ))
 
                            }
 
                        },
 
                        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(ParseError2::new_error(
 
                                        &ctx.modules[root_id.index as usize].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(ParseError2::new_error(
 
                                        &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                                        "Unknown type"
 
                                    ))
 
                                }
 
                            }
 

	
 
                            // Found a match, make sure it is a datatype
 
                            if !(definition.is_struct() || definition.is_enum()) {
 
                                return Err(ParseError2::new_error(
 
                                    &ctx.modules[root_id.index as usize].source, symbolic.identifier.position,
 
                                    "Embedded types must be datatypes (structs or enums)"
 
                                ))
 
                            }
 

	
 
                            // 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.
 
                            for poly_arg_type_id in &symbolic.poly_args {
 
                                self.parser_type_iter.push_back(*poly_arg_type_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_args(&self, poly_args: &[Identifier]) -> Vec<PolyArg> {
 
        poly_args
 
            .iter()
 
            .map(|v| PolyArg{ 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, poly_args: &mut [PolyArg], root_id: RootId, embedded_type_id: ParserTypeId,
 
    ) -> Result<(), ParseError2> {
 
        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 symbolix
 
                    self.parser_type_iter.push_back(*subtype_id);
 
                },
 
                PTV::Symbolic(symbolic) => {
 
                    for (poly_arg_idx, poly_arg) in poly_args.iter_mut().enumerate() {
 
                        if poly_arg.identifier.value == symbolic.identifier.value {
 
                            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.poly_args.is_empty(), "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(poly_arg_idx));
 
                            continue 'type_loop;
 
                        }
 
                    }
 

	
 
                    // Must match a definition
 
                    let symbol = ctx.symbols.resolve_namespaced_symbol(root_id, &symbolic.identifier);
 
                    debug_assert!(symbol.is_some(), "could not resolve symbolic parser type when determining poly args");
 
                    let (symbol, ident_iter) = 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
 
                    let defined_type = self.lookup.get(&definition_id).unwrap();
 
                    if cfg!(debug_assertions) {
 
                        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"
 
                        );
 
                    }
 
    
 
                    if symbolic.poly_args.len() != defined_type.poly_args.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_args.is_empty() {
 
                            String::from("is not polymorphic")
 
                        } else {
 
                            format!("accepts {} polymorphic arguments", defined_type.poly_args.len())
 
                        };
 
    
 
                        return Err(ParseError2::new_error(
 
                            module_source, symbolic.identifier.position,
 
                            &format!(
 
                                "The type '{}' {}, but {} polymorphic arguments were provided",
 
                                String::from_utf8_lossy(&symbolic.identifier.value),
 
                                number_args_msg, symbolic.poly_args.len()
 
                            )
 
                        ));
 
                    }
 
    
 
                    self.parser_type_iter.extend(&symbolic.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<(), ParseError2> {
 
        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.value == other_item_ident.value {
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 
                    return Err(ParseError2::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)
 
                    ));
 
                }
 
            }
 
        }
 

	
 
        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<(), ParseError2> {
 
        // 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.value == other_poly_arg.value {
 
                    let module_source = &ctx.modules[root_id.index as usize].source;
 
                    return Err(ParseError2::new_error(
 
                        module_source, poly_arg.position,
 
                        "This polymorphic argument is defined more than once"
 
                    ).with_postfixed_info(
 
                        module_source, other_poly_arg.position,
 
                        "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) {
 
                // We have a conflict
 
                let module_source = &ctx.modules[root_id.index as usize].source;
 
                return Err(ParseError2::new_error(
 
                    module_source, poly_arg.position,
 
                    "This polymorphic argument conflicts with another symbol"
 
                ).with_postfixed_info(
 
                    module_source, symbol.position,
 
                    "It conflicts due to this symbol"
 
                ));
 
            }
 
        }
 

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

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

	
 
    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.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::{symbol_table::*, type_table::*, LexedModule};
 

	
 
type Unit = ();
 
pub(crate) type VisitorResult = Result<Unit, ParseError2>;
 

	
 
/// Globally configured vector capacity for statement buffers in visitor 
 
/// implementations
 
pub(crate) const STMT_BUFFER_INIT_CAPACITY: usize = 256;
 
/// Globally configured vector capacity for expression buffers in visitor
 
/// implementations
 
pub(crate) const EXPR_BUFFER_INIT_CAPACITY: usize = 256;
 
/// Globally configured vector capacity for parser type buffers in visitor
 
/// implementations
 
pub(crate) const TYPE_BUFFER_INIT_CAPACITY: usize = 128;
 

	
 
/// General context structure that is used while traversing the AST.
 
pub(crate) struct Ctx<'p> {
 
    pub heap: &'p mut Heap,
 
    pub module: &'p LexedModule,
 
    pub symbols: &'p mut SymbolTable,
 
    pub types: &'p mut TypeTable,
 
}
 

	
 
/// Visitor is a generic trait that will fully walk the AST. The default
 
/// implementation of the visitors is to not recurse. The exception is the
 
/// top-level `visit_definition`, `visit_stmt` and `visit_expr` methods, which
 
/// call the appropriate visitor function.
 
pub(crate) trait Visitor2 {
 
    // Entry point
 
    fn visit_module(&mut self, ctx: &mut Ctx) -> VisitorResult {
 
        let mut def_index = 0;
 
        loop {
 
            let definition_id = {
 
                let root = &ctx.heap[ctx.module.root_id];
 
                if def_index >= root.definitions.len() {
 
                    return Ok(())
 
                }
 

	
 
                root.definitions[def_index]
 
            };
 

	
 
            self.visit_definition(ctx, definition_id)?;
 
            def_index += 1;
 
        }
 
    }
 

	
 
    // Definitions
 
    // --- enum matching
 
    fn visit_definition(&mut self, ctx: &mut Ctx, id: DefinitionId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Definition::Enum(def) => {
 
                let def = def.this;
 
                self.visit_enum_definition(ctx, def)
 
            },
 
            Definition::Struct(def) => {
 
                let def = def.this;
 
                self.visit_struct_definition(ctx, def)
 
            },
 
            Definition::Component(def) => {
 
                let def = def.this;
 
                self.visit_component_definition(ctx, def)
 
            },
 
            Definition::Function(def) => {
 
                let def = def.this;
 
                self.visit_function_definition(ctx, def)
 
            }
 
        }
 
    }
 

	
 
    // --- enum variant handling
 
    fn visit_enum_definition(&mut self, _ctx: &mut Ctx, _id: EnumId) -> VisitorResult { Ok(()) }
 
    fn visit_struct_definition(&mut self, _ctx: &mut Ctx, _id: StructId) -> VisitorResult { Ok(()) }
 
    fn visit_component_definition(&mut self, _ctx: &mut Ctx, _id: ComponentId) -> VisitorResult { Ok(()) }
 
    fn visit_function_definition(&mut self, _ctx: &mut Ctx, _id: FunctionId) -> VisitorResult { Ok(()) }
 

	
 
    // Statements
 
    // --- enum matching
 
    fn visit_stmt(&mut self, ctx: &mut Ctx, id: StatementId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Statement::Block(stmt) => {
 
                let this = stmt.this;
 
                self.visit_block_stmt(ctx, this)
 
            },
 
            Statement::Local(stmt) => {
 
                let this = stmt.this();
 
                self.visit_local_stmt(ctx, this)
 
            },
 
            Statement::Skip(stmt) => {
 
                let this = stmt.this;
 
                self.visit_skip_stmt(ctx, this)
 
            },
 
            Statement::Labeled(stmt) => {
 
                let this = stmt.this;
 
                self.visit_labeled_stmt(ctx, this)
 
            },
 
            Statement::If(stmt) => {
 
                let this = stmt.this;
 
                self.visit_if_stmt(ctx, this)
 
            },
 
            Statement::EndIf(_stmt) => Ok(()),
 
            Statement::While(stmt) => {
 
                let this = stmt.this;
 
                self.visit_while_stmt(ctx, this)
 
            },
 
            Statement::EndWhile(_stmt) => Ok(()),
 
            Statement::Break(stmt) => {
 
                let this = stmt.this;
 
                self.visit_break_stmt(ctx, this)
 
            },
 
            Statement::Continue(stmt) => {
 
                let this = stmt.this;
 
                self.visit_continue_stmt(ctx, this)
 
            },
 
            Statement::Synchronous(stmt) => {
 
                let this = stmt.this;
 
                self.visit_synchronous_stmt(ctx, this)
 
            },
 
            Statement::EndSynchronous(_stmt) => Ok(()),
 
            Statement::Return(stmt) => {
 
                let this = stmt.this;
 
                self.visit_return_stmt(ctx, this)
 
            },
 
            Statement::Assert(stmt) => {
 
                let this = stmt.this;
 
                self.visit_assert_stmt(ctx, this)
 
            },
 
            Statement::Goto(stmt) => {
 
                let this = stmt.this;
 
                self.visit_goto_stmt(ctx, this)
 
            },
 
            Statement::New(stmt) => {
 
                let this = stmt.this;
 
                self.visit_new_stmt(ctx, this)
 
            },
 
            Statement::Put(stmt) => {
 
                let this = stmt.this;
 
                self.visit_put_stmt(ctx, this)
 
            },
 
            Statement::Expression(stmt) => {
 
                let this = stmt.this;
 
                self.visit_expr_stmt(ctx, this)
 
            }
 
        }
 
    }
 

	
 
    fn visit_local_stmt(&mut self, ctx: &mut Ctx, id: LocalStatementId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            LocalStatement::Channel(stmt) => {
 
                let this = stmt.this;
 
                self.visit_local_channel_stmt(ctx, this)
 
            },
 
            LocalStatement::Memory(stmt) => {
 
                let this = stmt.this;
 
                self.visit_local_memory_stmt(ctx, this)
 
            },
 
        }
 
    }
 

	
 
    // --- enum variant handling
 
    fn visit_block_stmt(&mut self, _ctx: &mut Ctx, _id: BlockStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_local_memory_stmt(&mut self, _ctx: &mut Ctx, _id: MemoryStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_local_channel_stmt(&mut self, _ctx: &mut Ctx, _id: ChannelStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_skip_stmt(&mut self, _ctx: &mut Ctx, _id: SkipStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_labeled_stmt(&mut self, _ctx: &mut Ctx, _id: LabeledStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_if_stmt(&mut self, _ctx: &mut Ctx, _id: IfStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_while_stmt(&mut self, _ctx: &mut Ctx, _id: WhileStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_break_stmt(&mut self, _ctx: &mut Ctx, _id: BreakStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_continue_stmt(&mut self, _ctx: &mut Ctx, _id: ContinueStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_synchronous_stmt(&mut self, _ctx: &mut Ctx, _id: SynchronousStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_return_stmt(&mut self, _ctx: &mut Ctx, _id: ReturnStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_assert_stmt(&mut self, _ctx: &mut Ctx, _id: AssertStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_goto_stmt(&mut self, _ctx: &mut Ctx, _id: GotoStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_new_stmt(&mut self, _ctx: &mut Ctx, _id: NewStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_put_stmt(&mut self, _ctx: &mut Ctx, _id: PutStatementId) -> VisitorResult { Ok(()) }
 
    fn visit_expr_stmt(&mut self, _ctx: &mut Ctx, _id: ExpressionStatementId) -> VisitorResult { Ok(()) }
 

	
 
    // Expressions
 
    // --- enum matching
 
    fn visit_expr(&mut self, ctx: &mut Ctx, id: ExpressionId) -> VisitorResult {
 
        match &ctx.heap[id] {
 
            Expression::Assignment(expr) => {
 
                let this = expr.this;
 
                self.visit_assignment_expr(ctx, this)
 
            },
 
            Expression::Conditional(expr) => {
 
                let this = expr.this;
 
                self.visit_conditional_expr(ctx, this)
 
            }
 
            Expression::Binary(expr) => {
 
                let this = expr.this;
 
                self.visit_binary_expr(ctx, this)
 
            }
 
            Expression::Unary(expr) => {
 
                let this = expr.this;
 
                self.visit_unary_expr(ctx, this)
 
            }
 
            Expression::Indexing(expr) => {
 
                let this = expr.this;
 
                self.visit_indexing_expr(ctx, this)
 
            }
 
            Expression::Slicing(expr) => {
 
                let this = expr.this;
 
                self.visit_slicing_expr(ctx, this)
 
            }
 
            Expression::Select(expr) => {
 
                let this = expr.this;
 
                self.visit_select_expr(ctx, this)
 
            }
 
            Expression::Array(expr) => {
 
                let this = expr.this;
 
                self.visit_array_expr(ctx, this)
 
            }
 
            Expression::Constant(expr) => {
 
                let this = expr.this;
 
                self.visit_constant_expr(ctx, this)
 
            }
 
            Expression::Call(expr) => {
 
                let this = expr.this;
 
                self.visit_call_expr(ctx, this)
 
            }
 
            Expression::Variable(expr) => {
 
                let this = expr.this;
 
                self.visit_variable_expr(ctx, this)
 
            }
 
        }
 
    }
 

	
 
    fn visit_assignment_expr(&mut self, _ctx: &mut Ctx, _id: AssignmentExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_conditional_expr(&mut self, _ctx: &mut Ctx, _id: ConditionalExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_binary_expr(&mut self, _ctx: &mut Ctx, _id: BinaryExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_unary_expr(&mut self, _ctx: &mut Ctx, _id: UnaryExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_indexing_expr(&mut self, _ctx: &mut Ctx, _id: IndexingExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_slicing_expr(&mut self, _ctx: &mut Ctx, _id: SlicingExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_select_expr(&mut self, _ctx: &mut Ctx, _id: SelectExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_array_expr(&mut self, _ctx: &mut Ctx, _id: ArrayExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_constant_expr(&mut self, _ctx: &mut Ctx, _id: ConstantExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_call_expr(&mut self, _ctx: &mut Ctx, _id: CallExpressionId) -> VisitorResult { Ok(()) }
 
    fn visit_variable_expr(&mut self, _ctx: &mut Ctx, _id: VariableExpressionId) -> VisitorResult { Ok(()) }
 

	
 
    // Types
 
    fn visit_parser_type(&mut self, _ctx: &mut Ctx, _id: ParserTypeId) -> VisitorResult { Ok(()) }
 
}
 
\ No newline at end of file
src/protocol/parser/visitor_linker.rs
Show inline comments
 
use std::mem::{replace, swap};
 

	
 
use crate::protocol::ast::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::{symbol_table::*, type_table::*};
 

	
 
use super::visitor::{
 
    STMT_BUFFER_INIT_CAPACITY,
 
    EXPR_BUFFER_INIT_CAPACITY,
 
    TYPE_BUFFER_INIT_CAPACITY,
 
    Ctx, 
 
    Visitor2, 
 
    VisitorResult
 
};
 
use crate::protocol::ast::ExpressionParent::ExpressionStmt;
 

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

	
 
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::Primitive,
 
            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::Primitive;
 
        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();
 
    }
 
}
 

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

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

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

	
 
        // 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.performing_breadth_pass = false;
 
        self.visit_stmt(ctx, body_id)
 
    }
 

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

	
 
        // Set internal statement indices
 
        self.def_type = DefinitionType::Function;
 
        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.performing_breadth_pass = false;
 
        self.visit_stmt(ctx, body_id)
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // 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);
 
            self.expr_parent = ExpressionParent::Memory(id);
 
            self.visit_expr(ctx, ctx.heap[id].initial)?;
 
            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 {
 
            // 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(
 
                    ParseError2::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 != DefinitionType::Primitive {
 
            if !self.def_type.is_primitive() {
 
                return Err(ParseError2::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 != DefinitionType::Function {
 
            if !self.def_type.is_function() {
 
                return Err(
 
                    ParseError2::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 == DefinitionType::Function {
 
            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(
 
                    ParseError2::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(
 
                    ParseError2::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(
 
                    ParseError2::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 != DefinitionType::Composite {
 
            if !self.def_type.is_composite() {
 
                let new_stmt = &ctx.heap[id];
 
                return Err(
 
                    ParseError2::new_error(&ctx.module.source, new_stmt.position, "Instantiating components may only be done in composite components")
 
                );
 
            }
 

	
 
            // No fancy recursive parsing, must be followed by a call expression
 
            let definition_id = {
 
                let call_expr = &ctx.heap[call_expr_id];
 
                if let Method::Symbolic(symbolic) = &call_expr.method {
 
                    let found_symbol = self.find_symbol_of_type(
 
                        ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                        &symbolic.identifier, TypeClass::Component
 
                    );
 

	
 
                    match found_symbol {
 
                        FindOfTypeResult::Found(definition_id) => definition_id,
 
                        FindOfTypeResult::TypeMismatch(got_type_class) => {
 
                            return Err(ParseError2::new_error(
 
                                &ctx.module.source, symbolic.identifier.position,
 
                                &format!("New must instantiate a component, this identifier points to a {}", got_type_class)
 
                            ))
 
                        },
 
                        FindOfTypeResult::NotFound => {
 
                            return Err(ParseError2::new_error(
 
                                &ctx.module.source, symbolic.identifier.position,
 
                                "Could not find a defined component with this name"
 
                            ))
 
                        }
 
                    }
 
                } else {
 
                    return Err(
 
                        ParseError2::new_error(&ctx.module.source, call_expr.position, "Must instantiate a component")
 
                    );
 
                }
 
            };
 

	
 
            // Modify new statement's symbolic call to point to the appropriate
 
            // definition.
 
            let call_expr = &mut ctx.heap[call_expr_id];
 
            match &mut call_expr.method {
 
                Method::Symbolic(method) => method.definition = Some(definition_id),
 
                _ => unreachable!()
 
            }
 
        } else {
 
            // Performing depth pass. The function definition should have been
 
            // resolved in the breadth pass, now we recurse to evaluate the
 
            // arguments
 
            // TODO: @cleanup Maybe just call `visit_call_expr`?
 
            let call_expr_id = ctx.heap[id].expression;
 
            let call_expr = &mut ctx.heap[call_expr_id];
 
            call_expr.parent = ExpressionParent::New(id);
 

	
 
            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;
 

	
 
            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(call_expr_id.upcast(), 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_put_stmt(&mut self, ctx: &mut Ctx, id: PutStatementId) -> VisitorResult {
 
        // TODO: Make `put` an expression. Perhaps silly, but much easier to
 
        //  perform typechecking
 
        if self.performing_breadth_pass {
 
            let put_stmt = &ctx.heap[id];
 
            if self.in_sync.is_none() {
 
                return Err(ParseError2::new_error(
 
                    &ctx.module.source, put_stmt.position, "Put must be called in a synchronous block"
 
                ));
 
            }
 
        } else {
 
            let put_stmt = &ctx.heap[id];
 
            let port = put_stmt.port;
 
            let message = put_stmt.message;
 

	
 
            debug_assert_eq!(self.expr_parent, ExpressionParent::None);
 
            self.expr_parent = ExpressionParent::Put(id, 0);
 
            self.visit_expr(ctx, port)?;
 
            self.expr_parent = ExpressionParent::Put(id, 1);
 
            self.visit_expr(ctx, message)?;
 
            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_constant_expr(&mut self, ctx: &mut Ctx, id: ConstantExpressionId) -> VisitorResult {
 
        debug_assert!(!self.performing_breadth_pass);
 

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

	
 
        // Resolve the method to the appropriate definition and check the
 
        // legality of the particular method call.
 
        match &mut call_expr.method {
 
            Method::Create => {},
 
            Method::Fires => {
 
                if self.def_type != DefinitionType::Primitive {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError2::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'fires' may only occur in primitive component definitions"
 
                    ));
 
                }
 
            },
 
            Method::Get => {
 
                if self.def_type != DefinitionType::Primitive {
 
                if !self.def_type.is_primitive() {
 
                    return Err(ParseError2::new_error(
 
                        &ctx.module.source, call_expr.position,
 
                        "A call to 'get' may only occur in primitive component definitions"
 
                    ));
 
                }
 
            },
 
            Method::Symbolic(symbolic) => {
 
                // Find symbolic method
 
                let found_symbol = self.find_symbol_of_type(
 
                    ctx.module.root_id, &ctx.symbols, &ctx.types,
 
                    &symbolic.identifier, TypeClass::Function
 
                );
 
                let definition_id = match found_symbol {
 
                    FindOfTypeResult::Found(definition_id) => definition_id,
 
                    FindOfTypeResult::TypeMismatch(got_type_class) => {
 
                        return Err(ParseError2::new_error(
 
                            &ctx.module.source, symbolic.identifier.position,
 
                            &format!("Only functions can be called, this identifier points to a {}", got_type_class)
 
                        ))
 
                    },
 
                    FindOfTypeResult::NotFound => {
 
                        return Err(ParseError2::new_error(
 
                            &ctx.module.source, symbolic.identifier.position,
 
                            &format!("Could not find a function with this name")
 
                        ))
 
                    }
 
                };
 

	
 
                symbolic.definition = Some(definition_id);
 
            }
 
        }
 

	
 
        // Parse all the arguments in the depth pass as well. Note that we check
 
        // the number of arguments in the type checker.
 
        let call_expr = &mut ctx.heap[id];
 
        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 {
 
        // We visit a particular type rooted in a non-ParserType node in the
 
        // AST. Within this function we set up a buffer to visit all nested
 
        // ParserType nodes.
 
        // The goal is to link symbolic ParserType instances to the appropriate
 
        // definition or symbolic type. Alternatively to throw an error if we
 
        // cannot resolve the ParserType to either of these (polymorphic) types.
 
        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];
 

	
 
            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 poly_vars = match self.def_type {
 
                        DefinitionType::None => unreachable!(),
 
                        DefinitionType::Primitive(id) => &ctx.heap[id].poly_vars,
 
                        DefinitionType::Composite(id) => &ctx.heap[id].poly_vars,
 
                        DefinitionType::Function(id) => &ctx.heap[id].poly_vars,
 
                    };
 

	
 
                    for (poly_var_idx, poly_var) in poly_vars.iter().enumerate() {
 
                        if symbolic.identifier.value == poly_var.value {
 

	
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        Ok(())
 
    }
 
}
 

	
 
enum FindOfTypeResult {
 
    // Identifier was exactly matched, type matched as well
 
    Found(DefinitionId),
 
    // Identifier was matched, but the type differs from the expected one
 
    TypeMismatch(&'static str),
 
    // Identifier could not be found
 
    NotFound,
 
}
 

	
 
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(())
 
    }
 

	
 
    //--------------------------------------------------------------------------
 
    // 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<(), ParseError2> {
 
        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(
 
                    ParseError2::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.value == other_local.identifier.value {
 
                    // Collision within this scope
 
                    return Err(
 
                        ParseError2::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.value == parameter.identifier.value {
 
                        return Err(
 
                            ParseError2::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, ParseError2> {
 
        debug_assert!(self.cur_scope.is_some());
 
        debug_assert!(identifier.num_namespaces > 0);
 

	
 
        // TODO: Update once globals are possible as well
 
        if identifier.num_namespaces > 1 {
 
            todo!("Implement namespaced constant seeking")
 
        }
 

	
 
        // 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 && local.identifier.value == identifier.value {
 
                    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 parameter.identifier.value == identifier.value {
 
                                return Ok(parameter_id.upcast());
 
                            }
 
                        }
 
                    },
 
                    _ => unreachable!(),
 
                }
 

	
 
                // Variable could not be found
 
                return Err(ParseError2::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<(), ParseError2> {
 
        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.value == label.label.value {
 
                    // Collision
 
                    return Err(
 
                        ParseError2::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, ParseError2> {
 
        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.value == identifier.value {
 
                    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(
 
                                ParseError2::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(ParseError2::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(
 
        &self, root_id: RootId, symbols: &SymbolTable, types: &TypeTable,
 
        identifier: &NamespacedIdentifier, expected_type_class: TypeClass
 
    ) -> FindOfTypeResult {
 
        // Find symbol associated with identifier
 
        let symbol = symbols.resolve_namespaced_symbol(root_id, &identifier);
 
        if symbol.is_none() { return FindOfTypeResult::NotFound; }
 

	
 
        let (symbol, iter) = symbol.unwrap();
 
        if iter.num_remaining() != 0 { return FindOfTypeResult::NotFound; }
 

	
 
        match &symbol.symbol {
 
            Symbol::Definition((_, definition_id)) => {
 
                // Make sure definition is of the expected type
 
                let definition_type = types.get_base_definition(&definition_id);
 
                debug_assert!(definition_type.is_some(), "Found symbol '{}' in symbol table, but not in type table", String::from_utf8_lossy(&identifier.value));
 
                let definition_type_class = definition_type.unwrap().definition.type_class();
 

	
 
                if definition_type_class != expected_type_class {
 
                    FindOfTypeResult::TypeMismatch(definition_type_class.display_name())
 
                } else {
 
                    FindOfTypeResult::Found(*definition_id)
 
                }
 
            },
 
            Symbol::Namespace(_) => FindOfTypeResult::TypeMismatch("namespace"),
 
        }
 
    }
 

	
 
    /// 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, ParseError2> {
 
        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) {
 
                        ParseError2::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(
 
                        ParseError2::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(
 
                        ParseError2::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(
 
                    ParseError2::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)
 
    }
 
}
 
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