Changeset - b4a9c41d70da
[Not reviewed]
0 5 1
MH - 4 years ago 2021-05-24 18:28:25
contact@maxhenger.nl
Initial casting implementation

Explicit casts can be performed with the syntax 'cast<type>(input)'
and implicit casts can be performed with the syntax 'cast(input)'
where the output type is determined by inference.

To prevent casting shenanigans we only allow casting of primitive
types and of types to themselves (essentially creating a copy).
6 files changed with 276 insertions and 23 deletions:
0 comments (0 inline, 0 general)
src/protocol/eval/executor.rs
Show inline comments
 

	
 
use std::collections::VecDeque;
 

	
 
use super::value::*;
 
use super::store::*;
 
use super::error::*;
 
use crate::protocol::*;
 
use crate::protocol::ast::*;
 
use crate::protocol::type_table::*;
 

	
 
macro_rules! debug_enabled { () => { false }; }
 
macro_rules! debug_log {
 
    ($format:literal) => {
 
        enabled_debug_print!(false, "exec", $format);
 
    };
 
    ($format:literal, $($args:expr),*) => {
 
        enabled_debug_print!(false, "exec", $format, $($args),*);
 
    };
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub(crate) enum ExprInstruction {
 
    EvalExpr(ExpressionId),
 
    PushValToFront,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub(crate) struct Frame {
 
    pub(crate) definition: DefinitionId,
 
    pub(crate) monomorph_idx: i32,
 
    pub(crate) position: StatementId,
 
    pub(crate) expr_stack: VecDeque<ExprInstruction>, // hack for expression evaluation, evaluated by popping from back
 
    pub(crate) expr_values: VecDeque<Value>, // hack for expression results, evaluated by popping from front/back
 
}
 

	
 
impl Frame {
 
    /// Creates a new execution frame. Does not modify the stack in any way.
 
    pub fn new(heap: &Heap, definition_id: DefinitionId, monomorph_idx: i32) -> Self {
 
        let definition = &heap[definition_id];
 
        let first_statement = match definition {
 
            Definition::Component(definition) => definition.body,
 
            Definition::Function(definition) => definition.body,
 
            _ => unreachable!("initializing frame with {:?} instead of a function/component", definition),
 
        };
 

	
 
        Frame{
 
            definition: definition_id,
 
            monomorph_idx,
 
            position: first_statement.upcast(),
 
            expr_stack: VecDeque::with_capacity(128),
 
            expr_values: VecDeque::with_capacity(128),
 
        }
 
    }
 

	
 
    /// Prepares a single expression for execution. This involves walking the
 
    /// expression tree and putting them in the `expr_stack` such that
 
    /// continuously popping from its back will evaluate the expression. The
 
    /// results of each expression will be stored by pushing onto `expr_values`.
 
    pub fn prepare_single_expression(&mut self, heap: &Heap, expr_id: ExpressionId) {
 
        debug_assert!(self.expr_stack.is_empty());
 
        self.expr_values.clear(); // May not be empty if last expression result(s) were discarded
 

	
 
        self.serialize_expression(heap, expr_id);
 
    }
 

	
 
    /// Prepares multiple expressions for execution (i.e. evaluating all
 
    /// function arguments or all elements of an array/union literal). Per
 
    /// expression this works the same as `prepare_single_expression`. However
 
    /// after each expression is evaluated we insert a `PushValToFront`
 
    /// instruction
 
    pub fn prepare_multiple_expressions(&mut self, heap: &Heap, expr_ids: &[ExpressionId]) {
 
        debug_assert!(self.expr_stack.is_empty());
 
        self.expr_values.clear();
 

	
 
        for expr_id in expr_ids {
 
            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
            self.serialize_expression(heap, *expr_id);
 
        }
 
    }
 

	
 
    /// Performs depth-first serialization of expression tree. Let's not care
 
    /// about performance for a temporary runtime implementation
 
    fn serialize_expression(&mut self, heap: &Heap, id: ExpressionId) {
 
        self.expr_stack.push_back(ExprInstruction::EvalExpr(id));
 

	
 
        match &heap[id] {
 
            Expression::Assignment(expr) => {
 
                self.serialize_expression(heap, expr.left);
 
                self.serialize_expression(heap, expr.right);
 
            },
 
            Expression::Binding(expr) => {
 
                todo!("implement binding expression");
 
            },
 
            Expression::Conditional(expr) => {
 
                self.serialize_expression(heap, expr.test);
 
            },
 
            Expression::Binary(expr) => {
 
                self.serialize_expression(heap, expr.left);
 
                self.serialize_expression(heap, expr.right);
 
            },
 
            Expression::Unary(expr) => {
 
                self.serialize_expression(heap, expr.expression);
 
            },
 
            Expression::Indexing(expr) => {
 
                self.serialize_expression(heap, expr.index);
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Slicing(expr) => {
 
                self.serialize_expression(heap, expr.from_index);
 
                self.serialize_expression(heap, expr.to_index);
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Select(expr) => {
 
                self.serialize_expression(heap, expr.subject);
 
            },
 
            Expression::Literal(expr) => {
 
                // Here we only care about literals that have subexpressions
 
                match &expr.value {
 
                    Literal::Null | Literal::True | Literal::False |
 
                    Literal::Character(_) | Literal::String(_) |
 
                    Literal::Integer(_) | Literal::Enum(_) => {
 
                        // No subexpressions
 
                    },
 
                    Literal::Struct(literal) => {
 
                        // Note: fields expressions are evaluated in programmer-
 
                        // specified order. But struct construction expects them
 
                        // in type-defined order. I might want to come back to
 
                        // this.
 
                        let mut _num_pushed = 0;
 
                        for want_field_idx in 0..literal.fields.len() {
 
                            for field in &literal.fields {
 
                                if field.field_idx == want_field_idx {
 
                                    _num_pushed += 1;
 
                                    self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                                    self.serialize_expression(heap, field.value);
 
                                }
 
                            }
 
                        }
 
                        debug_assert_eq!(_num_pushed, literal.fields.len())
 
                    },
 
                    Literal::Union(literal) => {
 
                        for value_expr_id in &literal.values {
 
                            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                            self.serialize_expression(heap, *value_expr_id);
 
                        }
 
                    },
 
                    Literal::Array(value_expr_ids) => {
 
                        for value_expr_id in value_expr_ids {
 
                            self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                            self.serialize_expression(heap, *value_expr_id);
 
                        }
 
                    }
 
                }
 
            },
 
            Expression::Cast(expr) => {
 
                self.serialize_expression(heap, expr.subject);
 
            }
 
            Expression::Call(expr) => {
 
                for arg_expr_id in &expr.arguments {
 
                    self.expr_stack.push_back(ExprInstruction::PushValToFront);
 
                    self.serialize_expression(heap, *arg_expr_id);
 
                }
 
            },
 
            Expression::Variable(expr) => {
 
                // No subexpressions
 
            }
 
        }
 
    }
 
}
 

	
 
type EvalResult = Result<EvalContinuation, EvalError>;
 

	
 
pub enum EvalContinuation {
 
    Stepping,
 
    Inconsistent,
 
    Terminal,
 
    SyncBlockStart,
 
    SyncBlockEnd,
 
    NewComponent(DefinitionId, i32, ValueGroup),
 
    BlockFires(Value),
 
    BlockGet(Value),
 
    Put(Value, Value),
 
}
 

	
 
// Note: cloning is fine, methinks. cloning all values and the heap regions then
 
// we end up with valid "pointers" to heap regions.
 
#[derive(Debug, Clone)]
 
pub struct Prompt {
 
    pub(crate) frames: Vec<Frame>,
 
    pub(crate) store: Store,
 
}
 

	
 
impl Prompt {
 
    pub fn new(_types: &TypeTable, heap: &Heap, def: DefinitionId, monomorph_idx: i32, args: ValueGroup) -> Self {
 
        let mut prompt = Self{
 
            frames: Vec::new(),
 
            store: Store::new(),
 
        };
 

	
 
        // Maybe do typechecking in the future?
 
        debug_assert!((monomorph_idx as usize) < _types.get_base_definition(&def).unwrap().definition.procedure_monomorphs().len());
 
        prompt.frames.push(Frame::new(heap, def, monomorph_idx));
 
        args.into_store(&mut prompt.store);
 

	
 
        prompt
 
    }
 

	
 
    pub(crate) fn step(&mut self, types: &TypeTable, heap: &Heap, modules: &[Module], ctx: &mut EvalContext) -> EvalResult {
 
        // Helper function to transfer multiple values from the expression value
 
        // array into a heap region (e.g. constructing arrays or structs).
 
        fn transfer_expression_values_front_into_heap(cur_frame: &mut Frame, store: &mut Store, num_values: usize) -> HeapPos {
 
            let heap_pos = store.alloc_heap();
 

	
 
            // Do the transformation first (because Rust...)
 
            for val_idx in 0..num_values {
 
                cur_frame.expr_values[val_idx] = store.read_take_ownership(cur_frame.expr_values[val_idx].clone());
 
            }
 

	
 
            // And now transfer to the heap region
 
            let values = &mut store.heap_regions[heap_pos as usize].values;
 
            debug_assert!(values.is_empty());
 
            values.reserve(num_values);
 
            for _ in 0..num_values {
 
                values.push(cur_frame.expr_values.pop_front().unwrap());
 
            }
 

	
 
            heap_pos
 
        }
 

	
 
        // Helper function to make sure that an index into an aray is valid.
 
        fn array_inclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
 
            let array_len = store.heap_regions[array_heap_pos as usize].values.len();
 
            return idx < 0 || idx >= array_len as i64;
 
        }
 

	
 
        fn array_exclusive_index_is_invalid(store: &Store, array_heap_pos: u32, idx: i64) -> bool {
 
            let array_len = store.heap_regions[array_heap_pos as usize].values.len();
 
            return idx < 0 || idx > array_len as i64;
 
        }
 

	
 
        fn construct_array_error(prompt: &Prompt, modules: &[Module], heap: &Heap, expr_id: ExpressionId, heap_pos: u32, idx: i64) -> EvalError {
 
            let array_len = prompt.store.heap_regions[heap_pos as usize].values.len();
 
            return EvalError::new_error_at_expr(
 
                prompt, modules, heap, expr_id,
 
                format!("index {} is out of bounds: array length is {}", idx, array_len)
 
            )
 
        }
 

	
 
        // Checking if we're at the end of execution
 
        let cur_frame = self.frames.last_mut().unwrap();
 
        if cur_frame.position.is_invalid() {
 
            if heap[cur_frame.definition].is_function() {
 
                todo!("End of function without return, return an evaluation error");
 
            }
 
            return Ok(EvalContinuation::Terminal);
 
        }
 

	
 
        debug_log!("Taking step in '{}'", heap[cur_frame.definition].identifier().value.as_str());
 

	
 
        // Execute all pending expressions
 
        while !cur_frame.expr_stack.is_empty() {
 
            let next = cur_frame.expr_stack.pop_back().unwrap();
 
            debug_log!("Expr stack: {:?}", next);
 
            match next {
 
                ExprInstruction::PushValToFront => {
 
                    cur_frame.expr_values.rotate_right(1);
 
                },
 
                ExprInstruction::EvalExpr(expr_id) => {
 
                    let expr = &heap[expr_id];
 
                    match expr {
 
                        Expression::Assignment(expr) => {
 
                            let to = cur_frame.expr_values.pop_back().unwrap().as_ref();
 
                            let rhs = cur_frame.expr_values.pop_back().unwrap();
 

	
 
                            // Note: although not pretty, the assignment operator takes ownership
 
                            // of the right-hand side value when possible. So we do not drop the
 
                            // rhs's optionally owned heap data.
 
                            let rhs = self.store.read_take_ownership(rhs);
 
                            apply_assignment_operator(&mut self.store, to, expr.operation, rhs);
 
                        },
 
                        Expression::Binding(_expr) => {
 
                            todo!("Binding expression");
 
                        },
 
                        Expression::Conditional(expr) => {
 
                            // Evaluate testing expression, then extend the
 
                            // expression stack with the appropriate expression
 
                            let test_result = cur_frame.expr_values.pop_back().unwrap().as_bool();
 
                            if test_result {
 
                                cur_frame.serialize_expression(heap, expr.true_expression);
 
                            } else {
 
                                cur_frame.serialize_expression(heap, expr.false_expression);
 
                            }
 
                        },
 
                        Expression::Binary(expr) => {
 
                            let lhs = cur_frame.expr_values.pop_back().unwrap();
 
                            let rhs = cur_frame.expr_values.pop_back().unwrap();
 
                            let result = apply_binary_operator(&mut self.store, &lhs, expr.operation, &rhs);
 
                            cur_frame.expr_values.push_back(result);
 
                            self.store.drop_value(lhs.get_heap_pos());
 
                            self.store.drop_value(rhs.get_heap_pos());
 
                        },
 
                        Expression::Unary(expr) => {
 
                            let val = cur_frame.expr_values.pop_back().unwrap();
 
                            let result = apply_unary_operator(&mut self.store, expr.operation, &val);
 
                            cur_frame.expr_values.push_back(result);
 
                            self.store.drop_value(val.get_heap_pos());
 
                        },
 
                        Expression::Indexing(expr) => {
 
                            // Evaluate index. Never heap allocated so we do
 
                            // not have to drop it.
 
                            let index = cur_frame.expr_values.pop_back().unwrap();
 
                            let index = self.store.maybe_read_ref(&index);
 

	
 
                            debug_assert!(index.is_integer());
 
                            let index = if index.is_signed_integer() {
 
                                index.as_signed_integer() as i64
 
                            } else {
 
                                index.as_unsigned_integer() as i64
 
                            };
 

	
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 

	
 
                            let (deallocate_heap_pos, value_to_push, subject_heap_pos) = match subject {
 
                                Value::Ref(value_ref) => {
 
                                    // Our expression stack value is a reference to something that
 
                                    // exists in the normal stack/heap. We don't want to deallocate
 
                                    // this thing. Rather we want to return a reference to it.
 
                                    let subject = self.store.read_ref(value_ref);
 
                                    let subject_heap_pos = subject.as_array();
 

	
 
                                    if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
 
                                        return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
 
                                    }
 

	
 
                                    (None, Value::Ref(ValueId::Heap(subject_heap_pos, index as u32)), subject_heap_pos)
 
                                },
 
                                _ => {
 
                                    // Our value lives on the expression stack, hence we need to
 
                                    // clone whatever we're referring to. Then drop the subject.
 
                                    let subject_heap_pos = subject.as_array();
 

	
 
                                    if array_inclusive_index_is_invalid(&self.store, subject_heap_pos, index) {
 
                                        return Err(construct_array_error(self, modules, heap, expr_id, subject_heap_pos, index));
 
                                    }
 

	
 
                                    let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, index as u32));
 
                                    (Some(subject_heap_pos), self.store.clone_value(subject_indexed), subject_heap_pos)
 
                                },
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value_to_push);
 
                            self.store.drop_value(deallocate_heap_pos);
 
                        },
 
                        Expression::Slicing(expr) => {
 
                            // Evaluate indices
 
                            let from_index = cur_frame.expr_values.pop_back().unwrap();
 
                            let from_index = self.store.maybe_read_ref(&from_index);
 
                            let to_index = cur_frame.expr_values.pop_back().unwrap();
 
                            let to_index = self.store.maybe_read_ref(&to_index);
 

	
 
                            debug_assert!(from_index.is_integer() && to_index.is_integer());
 
                            let from_index = if from_index.is_signed_integer() {
 
                                from_index.as_signed_integer()
 
                            } else {
 
                                from_index.as_unsigned_integer() as i64
 
                            };
 
                            let to_index = if to_index.is_signed_integer() {
 
                                to_index.as_signed_integer()
 
                            } else {
 
                                to_index.as_unsigned_integer() as i64
 
                            };
 

	
 
                            // Dereference subject if needed
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 
                            let deref_subject = self.store.maybe_read_ref(&subject);
 

	
 
                            // Slicing needs to produce a copy anyway (with the
 
                            // current evaluator implementation)
 
                            let array_heap_pos = deref_subject.as_array();
 
                            if array_inclusive_index_is_invalid(&self.store, array_heap_pos, from_index) {
 
                                return Err(construct_array_error(self, modules, heap, expr.from_index, array_heap_pos, from_index));
 
                            }
 
                            if array_exclusive_index_is_invalid(&self.store, array_heap_pos, to_index) {
 
                                return Err(construct_array_error(self, modules, heap, expr.to_index, array_heap_pos, to_index));
 
                            }
 

	
 
                            // Again: would love to push directly, but rust...
 
                            let new_heap_pos = self.store.alloc_heap();
 
                            debug_assert!(self.store.heap_regions[new_heap_pos as usize].values.is_empty());
 
                            if to_index > from_index {
 
                                let from_index = from_index as usize;
 
                                let to_index = to_index as usize;
 
                                let mut values = Vec::with_capacity(to_index - from_index);
 
                                for idx in from_index..to_index {
 
                                    let value = self.store.heap_regions[array_heap_pos as usize].values[idx].clone();
 
                                    values.push(self.store.clone_value(value));
 
                                }
 

	
 
                                self.store.heap_regions[new_heap_pos as usize].values = values;
 

	
 
                            } // else: empty range
 

	
 
                            cur_frame.expr_values.push_back(Value::Array(new_heap_pos));
 

	
 
                            // Dropping the original subject, because we don't
 
                            // want to drop something on the stack
 
                            self.store.drop_value(subject.get_heap_pos());
 
                        },
 
                        Expression::Select(expr) => {
 
                            let subject= cur_frame.expr_values.pop_back().unwrap();
 
                            let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                            let field_idx = mono_data.expr_data[expr.unique_id_in_definition as usize].field_or_monomorph_idx as u32;
 

	
 
                            // Note: same as above: clone if value lives on expr stack, simply
 
                            // refer to it if it already lives on the stack/heap.
 
                            let (deallocate_heap_pos, value_to_push) = match subject {
 
                                Value::Ref(value_ref) => {
 
                                    let subject = self.store.read_ref(value_ref);
 
                                    let subject_heap_pos = subject.as_struct();
 

	
 
                                    (None, Value::Ref(ValueId::Heap(subject_heap_pos, field_idx)))
 
                                },
 
                                _ => {
 
                                    let subject_heap_pos = subject.as_struct();
 
                                    let subject_indexed = Value::Ref(ValueId::Heap(subject_heap_pos, field_idx));
 
                                    (Some(subject_heap_pos), self.store.clone_value(subject_indexed))
 
                                },
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value_to_push);
 
                            self.store.drop_value(deallocate_heap_pos);
 
                        },
 
                        Expression::Literal(expr) => {
 
                            let value = match &expr.value {
 
                                Literal::Null => Value::Null,
 
                                Literal::True => Value::Bool(true),
 
                                Literal::False => Value::Bool(false),
 
                                Literal::Character(lit_value) => Value::Char(*lit_value),
 
                                Literal::String(lit_value) => {
 
                                    let heap_pos = self.store.alloc_heap();
 
                                    let values = &mut self.store.heap_regions[heap_pos as usize].values;
 
                                    let value = lit_value.as_str();
 
                                    debug_assert!(values.is_empty());
 
                                    values.reserve(value.len());
 
                                    for character in value.as_bytes() {
 
                                        debug_assert!(character.is_ascii());
 
                                        values.push(Value::Char(*character as char));
 
                                    }
 
                                    Value::String(heap_pos)
 
                                }
 
                                Literal::Integer(lit_value) => {
 
                                    use ConcreteTypePart as CTP;
 
                                    let def_types = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                                    let concrete_type = &def_types.expr_data[expr.unique_id_in_definition as usize].expr_type;
 

	
 
                                    debug_assert_eq!(concrete_type.parts.len(), 1);
 
                                    match concrete_type.parts[0] {
 
                                        CTP::UInt8  => Value::UInt8(lit_value.unsigned_value as u8),
 
                                        CTP::UInt16 => Value::UInt16(lit_value.unsigned_value as u16),
 
                                        CTP::UInt32 => Value::UInt32(lit_value.unsigned_value as u32),
 
                                        CTP::UInt64 => Value::UInt64(lit_value.unsigned_value as u64),
 
                                        CTP::SInt8  => Value::SInt8(lit_value.unsigned_value as i8),
 
                                        CTP::SInt16 => Value::SInt16(lit_value.unsigned_value as i16),
 
                                        CTP::SInt32 => Value::SInt32(lit_value.unsigned_value as i32),
 
                                        CTP::SInt64 => Value::SInt64(lit_value.unsigned_value as i64),
 
                                        _ => unreachable!("got concrete type {:?} for integer literal at expr {:?}", concrete_type, expr_id),
 
                                    }
 
                                }
 
                                Literal::Struct(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.fields.len()
 
                                    );
 
                                    Value::Struct(heap_pos)
 
                                }
 
                                Literal::Enum(lit_value) => {
 
                                    Value::Enum(lit_value.variant_idx as i64)
 
                                }
 
                                Literal::Union(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.values.len()
 
                                    );
 
                                    Value::Union(lit_value.variant_idx as i64, heap_pos)
 
                                }
 
                                Literal::Array(lit_value) => {
 
                                    let heap_pos = transfer_expression_values_front_into_heap(
 
                                        cur_frame, &mut self.store, lit_value.len()
 
                                    );
 
                                    Value::Array(heap_pos)
 
                                }
 
                            };
 

	
 
                            cur_frame.expr_values.push_back(value);
 
                        },
 
                        Expression::Cast(expr) => {
 
                            let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                            let output_type = &mono_data.expr_data[expr.unique_id_in_definition as usize].expr_type;
 

	
 
                            // Typechecking reduced this to two cases: either we
 
                            // have casting noop (same types), or we're casting
 
                            // between integer/bool/char types.
 
                            let subject = cur_frame.expr_values.pop_back().unwrap();
 
                            match apply_casting(&mut self.store, output_type, &subject) {
 
                                Ok(value) => cur_frame.expr_values.push_back(value),
 
                                Err(msg) => {
 
                                    return Err(EvalError::new_error_at_expr(self, modules, heap, expr.this.upcast(), msg));
 
                                }
 
                            }
 

	
 
                            self.store.drop_value(subject.get_heap_pos());
 
                        }
 
                        Expression::Call(expr) => {
 
                            // Push a new frame. Note that all expressions have
 
                            // been pushed to the front, so they're in the order
 
                            // of the definition.
 
                            let num_args = expr.arguments.len();
 

	
 
                            // Determine stack boundaries
 
                            let cur_stack_boundary = self.store.cur_stack_boundary;
 
                            let new_stack_boundary = self.store.stack.len();
 

	
 
                            // Push new boundary and function arguments for new frame
 
                            self.store.stack.push(Value::PrevStackBoundary(cur_stack_boundary as isize));
 
                            for _ in 0..num_args {
 
                                let argument = self.store.read_take_ownership(cur_frame.expr_values.pop_front().unwrap());
 
                                self.store.stack.push(argument);
 
                            }
 

	
 
                            // Determine the monomorph index of the function we're calling
 
                            let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                            let call_data = &mono_data.expr_data[expr.unique_id_in_definition as usize];
 

	
 
                            // Push the new frame
 
                            self.frames.push(Frame::new(heap, expr.definition, call_data.field_or_monomorph_idx));
 
                            self.store.cur_stack_boundary = new_stack_boundary;
 

	
 
                            // To simplify the logic a little bit we will now
 
                            // return and ask our caller to call us again
 
                            return Ok(EvalContinuation::Stepping);
 
                        },
 
                        Expression::Variable(expr) => {
 
                            let variable = &heap[expr.declaration.unwrap()];
 
                            cur_frame.expr_values.push_back(Value::Ref(ValueId::Stack(variable.unique_id_in_scope as StackPos)));
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        debug_log!("Frame [{:?}] at {:?}, stack size = {}", cur_frame.definition, cur_frame.position, self.store.stack.len());
 
        if debug_enabled!() {
 
            debug_log!("Stack:");
 
            for (stack_idx, stack_val) in self.store.stack.iter().enumerate() {
 
                debug_log!("  [{:03}] {:?}", stack_idx, stack_val);
 
            }
 

	
 
            debug_log!("Heap:");
 
            for (heap_idx, heap_region) in self.store.heap_regions.iter().enumerate() {
 
                let is_free = self.store.free_regions.iter().any(|idx| *idx as usize == heap_idx);
 
                debug_log!("  [{:03}] in_use: {}, len: {}, vals: {:?}", heap_idx, !is_free, heap_region.values.len(), &heap_region.values);
 
            }
 
        }
 
        // No (more) expressions to evaluate. So evaluate statement (that may
 
        // depend on the result on the last evaluated expression(s))
 
        let stmt = &heap[cur_frame.position];
 
        let return_value = match stmt {
 
            Statement::Block(stmt) => {
 
                // Reserve space on stack, but also make sure excess stack space
 
                // is cleared
 
                self.store.clear_stack(stmt.first_unique_id_in_scope as usize);
 
                self.store.reserve_stack(stmt.next_unique_id_in_scope as usize);
 
                cur_frame.position = stmt.statements[0];
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndBlock(stmt) => {
 
                let block = &heap[stmt.start_block];
 
                self.store.clear_stack(block.first_unique_id_in_scope as usize);
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Local(stmt) => {
 
                match stmt {
 
                    LocalStatement::Memory(stmt) => {
 
                        let variable = &heap[stmt.variable];
 
                        self.store.write(ValueId::Stack(variable.unique_id_in_scope as u32), Value::Unassigned);
 

	
 
                        cur_frame.position = stmt.next;
 
                    },
 
                    LocalStatement::Channel(stmt) => {
 
                        let [from_value, to_value] = ctx.new_channel();
 
                        self.store.write(ValueId::Stack(heap[stmt.from].unique_id_in_scope as u32), from_value);
 
                        self.store.write(ValueId::Stack(heap[stmt.to].unique_id_in_scope as u32), to_value);
 

	
 
                        cur_frame.position = stmt.next;
 
                    }
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Labeled(stmt) => {
 
                cur_frame.position = stmt.body;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::If(stmt) => {
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for if statement");
 
                let test_value = cur_frame.expr_values.pop_back().unwrap().as_bool();
 
                if test_value {
 
                    cur_frame.position = stmt.true_body.upcast();
 
                } else if let Some(false_body) = stmt.false_body {
 
                    cur_frame.position = false_body.upcast();
 
                } else {
 
                    // Not true, and no false body
 
                    cur_frame.position = stmt.end_if.upcast();
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndIf(stmt) => {
 
                cur_frame.position = stmt.next;
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::While(stmt) => {
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for while statement");
 
                let test_value = cur_frame.expr_values.pop_back().unwrap().as_bool();
 
                if test_value {
 
                    cur_frame.position = stmt.body.upcast();
 
                } else {
 
                    cur_frame.position = stmt.end_while.upcast();
 
                }
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::EndWhile(stmt) => {
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Break(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Continue(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::Synchronous(stmt) => {
 
                cur_frame.position = stmt.body.upcast();
 

	
 
                Ok(EvalContinuation::SyncBlockStart)
 
            },
 
            Statement::EndSynchronous(stmt) => {
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::SyncBlockEnd)
 
            },
 
            Statement::Return(stmt) => {
 
                debug_assert!(heap[cur_frame.definition].is_function());
 
                debug_assert_eq!(cur_frame.expr_values.len(), 1, "expected one expr value for return statement");
 

	
 
                // The preceding frame has executed a call, so is expecting the
 
                // return expression on its expression value stack. Note that
 
                // we may be returning a reference to something on our stack,
 
                // so we need to read that value and clone it.
 
                let return_value = cur_frame.expr_values.pop_back().unwrap();
 
                let return_value = match return_value {
 
                    Value::Ref(value_id) => self.store.read_copy(value_id),
 
                    _ => return_value,
 
                };
 

	
 
                // Pre-emptively pop our stack frame
 
                self.frames.pop();
 

	
 
                // Clean up our section of the stack
 
                self.store.clear_stack(0);
 
                let prev_stack_idx = self.store.stack.pop().unwrap().as_stack_boundary();
 

	
 
                // TODO: Temporary hack for testing, remove at some point
 
                if self.frames.is_empty() {
 
                    debug_assert!(prev_stack_idx == -1);
 
                    debug_assert!(self.store.stack.len() == 0);
 
                    self.store.stack.push(return_value);
 
                    return Ok(EvalContinuation::Terminal);
 
                }
 

	
 
                debug_assert!(prev_stack_idx >= 0);
 
                // Return to original state of stack frame
 
                self.store.cur_stack_boundary = prev_stack_idx as usize;
 
                let cur_frame = self.frames.last_mut().unwrap();
 
                cur_frame.expr_values.push_back(return_value);
 

	
 
                // We just returned to the previous frame, which might be in
 
                // the middle of evaluating expressions for a particular
 
                // statement. So we don't want to enter the code below.
 
                return Ok(EvalContinuation::Stepping);
 
            },
 
            Statement::Goto(stmt) => {
 
                cur_frame.position = stmt.target.unwrap().upcast();
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
            Statement::New(stmt) => {
 
                let call_expr = &heap[stmt.expression];
 
                debug_assert!(heap[call_expr.definition].is_component());
 
                debug_assert_eq!(
 
                    cur_frame.expr_values.len(), heap[call_expr.definition].parameters().len(),
 
                    "mismatch in expr stack size and number of arguments for new statement"
 
                );
 

	
 
                let mono_data = types.get_procedure_expression_data(&cur_frame.definition, cur_frame.monomorph_idx);
 
                let expr_data = &mono_data.expr_data[call_expr.unique_id_in_definition as usize];
 

	
 
                // Note that due to expression value evaluation they exist in
 
                // reverse order on the stack.
 
                // TODO: Revise this code, keep it as is to be compatible with current runtime
 
                let mut args = Vec::new();
 
                while let Some(value) = cur_frame.expr_values.pop_front() {
 
                    args.push(value);
 
                }
 

	
 
                // Construct argument group, thereby copying heap regions
 
                let argument_group = ValueGroup::from_store(&self.store, &args);
 

	
 
                // Clear any heap regions
 
                for arg in &args {
 
                    self.store.drop_value(arg.get_heap_pos());
 
                }
 

	
 
                cur_frame.position = stmt.next;
 

	
 
                todo!("Make sure this is handled correctly, transfer 'heap' values to another Prompt");
 
                Ok(EvalContinuation::NewComponent(call_expr.definition, expr_data.field_or_monomorph_idx, argument_group))
 
            },
 
            Statement::Expression(stmt) => {
 
                // The expression has just been completely evaluated. Some
 
                // values might have remained on the expression value stack.
 
                cur_frame.expr_values.clear();
 
                cur_frame.position = stmt.next;
 

	
 
                Ok(EvalContinuation::Stepping)
 
            },
 
        };
 

	
 
        assert!(
 
            cur_frame.expr_values.is_empty(),
 
            "This is a debugging assertion that will fail if you perform expressions without \
 
            assigning to anything. This should be completely valid, and this assertion should be \
 
            replaced by something that clears the expression values if needed, but I'll keep this \
 
            in for now for debugging purposes."
 
        );
 

	
 
        // If the next statement requires evaluating expressions then we push
 
        // these onto the expression stack. This way we will evaluate this
 
        // stack in the next loop, then evaluate the statement using the result
 
        // from the expression evaluation.
 
        if !cur_frame.position.is_invalid() {
 
            let stmt = &heap[cur_frame.position];
 

	
 
            match stmt {
 
                Statement::If(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
 
                Statement::While(stmt) => cur_frame.prepare_single_expression(heap, stmt.test),
 
                Statement::Return(stmt) => {
 
                    debug_assert_eq!(stmt.expressions.len(), 1); // TODO: @ReturnValues
 
                    cur_frame.prepare_single_expression(heap, stmt.expressions[0]);
 
                },
 
                Statement::New(stmt) => {
 
                    // Note that we will end up not evaluating the call itself.
 
                    // Rather we will evaluate its expressions and then
 
                    // instantiate the component upon reaching the "new" stmt.
 
                    let call_expr = &heap[stmt.expression];
 
                    cur_frame.prepare_multiple_expressions(heap, &call_expr.arguments);
 
                },
 
                Statement::Expression(stmt) => {
 
                    cur_frame.prepare_single_expression(heap, stmt.expression);
 
                }
 
                _ => {},
 
            }
 
        }
 

	
 
        return_value
 
    }
 
}
 
\ No newline at end of file
src/protocol/eval/value.rs
Show inline comments
 

	
 
use super::store::*;
 
use crate::PortId;
 
use crate::protocol::ast::{
 
    AssignmentOperator,
 
    BinaryOperator,
 
    UnaryOperator,
 
    ConcreteType,
 
    ConcreteTypePart,
 
};
 
use crate::protocol::parser::token_parsing::*;
 

	
 
pub type StackPos = u32;
 
pub type HeapPos = u32;
 

	
 
#[derive(Debug, Copy, Clone)]
 
pub enum ValueId {
 
    Stack(StackPos), // place on stack
 
    Heap(HeapPos, u32), // allocated region + values within that region
 
}
 

	
 
/// Represents a value stored on the stack or on the heap. Some values contain
 
/// a `HeapPos`, implying that they're stored in the store's `Heap`. Clearing
 
/// a `Value` with a `HeapPos` from a stack must also clear the associated
 
/// region from the `Heap`.
 
#[derive(Debug, Clone)]
 
pub enum Value {
 
    // Special types, never encountered during evaluation if the compiler works correctly
 
    Unassigned,                 // Marker when variables are first declared, immediately followed by assignment
 
    PrevStackBoundary(isize),   // Marker for stack frame beginning, so we can pop stack values
 
    Ref(ValueId),               // Reference to a value, used by expressions producing references
 
    // Builtin types
 
    Input(PortId),
 
    Output(PortId),
 
    Message(HeapPos),
 
    Null,
 
    Bool(bool),
 
    Char(char),
 
    String(HeapPos),
 
    UInt8(u8),
 
    UInt16(u16),
 
    UInt32(u32),
 
    UInt64(u64),
 
    SInt8(i8),
 
    SInt16(i16),
 
    SInt32(i32),
 
    SInt64(i64),
 
    Array(HeapPos),
 
    // Instances of user-defined types
 
    Enum(i64),
 
    Union(i64, HeapPos),
 
    Struct(HeapPos),
 
}
 

	
 
macro_rules! impl_union_unpack_as_value {
 
    ($func_name:ident, $variant_name:path, $return_type:ty) => {
 
        impl Value {
 
            pub(crate) fn $func_name(&self) -> $return_type {
 
                match self {
 
                    $variant_name(v) => *v,
 
                    _ => panic!(concat!("called ", stringify!($func_name()), " on {:?}"), self),
 
                }
 
            }
 
        }
 
    }
 
}
 

	
 
impl_union_unpack_as_value!(as_stack_boundary, Value::PrevStackBoundary, isize);
 
impl_union_unpack_as_value!(as_ref,     Value::Ref,     ValueId);
 
impl_union_unpack_as_value!(as_input,   Value::Input,   PortId);
 
impl_union_unpack_as_value!(as_output,  Value::Output,  PortId);
 
impl_union_unpack_as_value!(as_message, Value::Message, HeapPos);
 
impl_union_unpack_as_value!(as_bool,    Value::Bool,    bool);
 
impl_union_unpack_as_value!(as_char,    Value::Char,    char);
 
impl_union_unpack_as_value!(as_string,  Value::String,  HeapPos);
 
impl_union_unpack_as_value!(as_uint8,   Value::UInt8,   u8);
 
impl_union_unpack_as_value!(as_uint16,  Value::UInt16,  u16);
 
impl_union_unpack_as_value!(as_uint32,  Value::UInt32,  u32);
 
impl_union_unpack_as_value!(as_uint64,  Value::UInt64,  u64);
 
impl_union_unpack_as_value!(as_sint8,   Value::SInt8,   i8);
 
impl_union_unpack_as_value!(as_sint16,  Value::SInt16,  i16);
 
impl_union_unpack_as_value!(as_sint32,  Value::SInt32,  i32);
 
impl_union_unpack_as_value!(as_sint64,  Value::SInt64,  i64);
 
impl_union_unpack_as_value!(as_array,   Value::Array,   HeapPos);
 
impl_union_unpack_as_value!(as_enum,    Value::Enum,    i64);
 
impl_union_unpack_as_value!(as_struct,  Value::Struct,  HeapPos);
 

	
 
impl Value {
 
    pub(crate) fn as_union(&self) -> (i64, HeapPos) {
 
        match self {
 
            Value::Union(tag, v) => (*tag, *v),
 
            _ => panic!("called as_union on {:?}", self),
 
        }
 
    }
 

	
 
    pub(crate) fn is_integer(&self) -> bool {
 
        match self {
 
            Value::UInt8(_) | Value::UInt16(_) | Value::UInt32(_) | Value::UInt64(_) |
 
            Value::SInt8(_) | Value::SInt16(_) | Value::SInt32(_) | Value::SInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn is_unsigned_integer(&self) -> bool {
 
        match self {
 
            Value::UInt8(_) | Value::UInt16(_) | Value::UInt32(_) | Value::UInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn is_signed_integer(&self) -> bool {
 
        match self {
 
            Value::SInt8(_) | Value::SInt16(_) | Value::SInt32(_) | Value::SInt64(_) => true,
 
            _ => false
 
        }
 
    }
 

	
 
    pub(crate) fn as_unsigned_integer(&self) -> u64 {
 
        match self {
 
            Value::UInt8(v)  => *v as u64,
 
            Value::UInt16(v) => *v as u64,
 
            Value::UInt32(v) => *v as u64,
 
            Value::UInt64(v) => *v as u64,
 
            _ => unreachable!("called as_unsigned_integer on {:?}", self),
 
        }
 
    }
 

	
 
    pub(crate) fn as_signed_integer(&self) -> i64 {
 
        match self {
 
            Value::SInt8(v)  => *v as i64,
 
            Value::SInt16(v) => *v as i64,
 
            Value::SInt32(v) => *v as i64,
 
            Value::SInt64(v) => *v as i64,
 
            _ => unreachable!("called as_signed_integer on {:?}", self)
 
        }
 
    }
 

	
 
    /// Returns the heap position associated with the value. If the value
 
    /// doesn't store anything in the heap then we return `None`.
 
    pub(crate) fn get_heap_pos(&self) -> Option<HeapPos> {
 
        match self {
 
            Value::Message(v) => Some(*v),
 
            Value::Array(v) => Some(*v),
 
            Value::Union(_, v) => Some(*v),
 
            Value::Struct(v) => Some(*v),
 
            _ => None
 
        }
 
    }
 
}
 

	
 
/// When providing arguments to a new component, or when transferring values
 
/// from one component's store to a newly instantiated component, one has to
 
/// transfer stack and heap values. This `ValueGroup` represents such a
 
/// temporary group of values with potential heap allocations.
 
///
 
/// Constructing such a ValueGroup manually requires some extra care to make
 
/// sure all elements of `values` point to valid elements of `regions`.
 
///
 
/// Again: this is a temporary thing, hopefully removed once we move to a
 
/// bytecode interpreter.
 
pub struct ValueGroup {
 
    pub(crate) values: Vec<Value>,
 
    pub(crate) regions: Vec<Vec<Value>>
 
}
 

	
 
impl ValueGroup {
 
    pub(crate) fn new_stack(values: Vec<Value>) -> Self {
 
        debug_assert!(values.iter().all(|v| v.get_heap_pos().is_none()));
 
        Self{
 
            values,
 
            regions: Vec::new(),
 
        }
 
    }
 
    pub(crate) fn from_store(store: &Store, values: &[Value]) -> Self {
 
        let mut group = ValueGroup{
 
            values: Vec::with_capacity(values.len()),
 
            regions: Vec::with_capacity(values.len()), // estimation
 
        };
 

	
 
        for value in values {
 
            let transferred = group.retrieve_value(value, store);
 
            group.values.push(transferred);
 
        }
 

	
 
        group
 
    }
 

	
 
    /// Transfers a provided value from a store into a local value with its
 
    /// heap allocations (if any) stored in the ValueGroup. Calling this
 
    /// function will not store the returned value in the `values` member.
 
    fn retrieve_value(&mut self, value: &Value, from_store: &Store) -> Value {
 
        if let Some(heap_pos) = value.get_heap_pos() {
 
            // Value points to a heap allocation, so transfer the heap values
 
            // internally.
 
            let from_region = &from_store.heap_regions[heap_pos as usize].values;
 
            let mut new_region = Vec::with_capacity(from_region.len());
 
            for value in from_region {
 
                let transferred = self.retrieve_value(value, from_store);
 
                new_region.push(transferred);
 
            }
 

	
 
            // Region is constructed, store internally and return the new value.
 
            let new_region_idx = self.regions.len() as HeapPos;
 
            self.regions.push(new_region);
 

	
 
            return match value {
 
                Value::Message(_)    => Value::Message(new_region_idx),
 
                Value::String(_)     => Value::String(new_region_idx),
 
                Value::Array(_)      => Value::Array(new_region_idx),
 
                Value::Union(tag, _) => Value::Union(*tag, new_region_idx),
 
                Value::Struct(_)     => Value::Struct(new_region_idx),
 
                _ => unreachable!(),
 
            };
 
        } else {
 
            return value.clone();
 
        }
 
    }
 

	
 
    /// Transfers the heap values and the stack values into the store. Stack
 
    /// values are pushed onto the Store's stack in the order in which they
 
    /// appear in the value group.
 
    pub(crate) fn into_store(self, store: &mut Store) {
 
        for value in &self.values {
 
            let transferred = self.provide_value(value, store);
 
            store.stack.push(transferred);
 
        }
 
    }
 

	
 
    fn provide_value(&self, value: &Value, to_store: &mut Store) -> Value {
 
        if let Some(from_heap_pos) = value.get_heap_pos() {
 
            let from_heap_pos = from_heap_pos as usize;
 
            let to_heap_pos = to_store.alloc_heap();
 
            let to_heap_pos_usize = to_heap_pos as usize;
 
            to_store.heap_regions[to_heap_pos_usize].values.reserve(self.regions[from_heap_pos].len());
 

	
 
            for value in &self.regions[from_heap_pos as usize] {
 
                let transferred = self.provide_value(value, to_store);
 
                to_store.heap_regions[to_heap_pos_usize].values.push(transferred);
 
            }
 

	
 
            return match value {
 
                Value::Message(_)    => Value::Message(to_heap_pos),
 
                Value::String(_)     => Value::String(to_heap_pos),
 
                Value::Array(_)      => Value::Array(to_heap_pos),
 
                Value::Union(tag, _) => Value::Union(*tag, to_heap_pos),
 
                Value::Struct(_)     => Value::Struct(to_heap_pos),
 
                _ => unreachable!(),
 
            };
 
        } else {
 
            return value.clone();
 
        }
 
    }
 
}
 

	
 
impl Default for ValueGroup {
 
    /// Returns an empty ValueGroup
 
    fn default() -> Self {
 
        Self { values: Vec::new(), regions: Vec::new() }
 
    }
 
}
 

	
 
pub(crate) fn apply_assignment_operator(store: &mut Store, lhs: ValueId, op: AssignmentOperator, rhs: Value) {
 
    use AssignmentOperator as AO;
 

	
 
    macro_rules! apply_int_op {
 
        ($lhs:ident, $assignment_tokens:tt, $operator:ident, $rhs:ident) => {
 
            match $lhs {
 
                Value::UInt8(v)  => { *v $assignment_tokens $rhs.as_uint8();  },
 
                Value::UInt16(v) => { *v $assignment_tokens $rhs.as_uint16(); },
 
                Value::UInt32(v) => { *v $assignment_tokens $rhs.as_uint32(); },
 
                Value::UInt64(v) => { *v $assignment_tokens $rhs.as_uint64(); },
 
                Value::SInt8(v)  => { *v $assignment_tokens $rhs.as_sint8();  },
 
                Value::SInt16(v) => { *v $assignment_tokens $rhs.as_sint16(); },
 
                Value::SInt32(v) => { *v $assignment_tokens $rhs.as_sint32(); },
 
                Value::SInt64(v) => { *v $assignment_tokens $rhs.as_sint64(); },
 
                _ => unreachable!("apply_assignment_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs),
 
            }
 
        }
 
    }
 

	
 
    // let rhs = store.maybe_read_ref(&rhs).clone(); // we don't own this thing, so don't drop it
 
    let lhs = store.read_mut_ref(lhs);
 

	
 
    let mut to_dealloc = None;
 
    match op {
 
        AO::Set => {
 
            match lhs {
 
                Value::Unassigned => { *lhs = rhs; },
 
                Value::Input(v)  => { *v = rhs.as_input(); },
 
                Value::Output(v) => { *v = rhs.as_output(); },
 
                Value::Message(v)  => { to_dealloc = Some(*v); *v = rhs.as_message(); },
 
                Value::Bool(v)    => { *v = rhs.as_bool(); },
 
                Value::Char(v) => { *v = rhs.as_char(); },
 
                Value::String(v) => { *v = rhs.as_string().clone(); },
 
                Value::UInt8(v) => { *v = rhs.as_uint8(); },
 
                Value::UInt16(v) => { *v = rhs.as_uint16(); },
 
                Value::UInt32(v) => { *v = rhs.as_uint32(); },
 
                Value::UInt64(v) => { *v = rhs.as_uint64(); },
 
                Value::SInt8(v) => { *v = rhs.as_sint8(); },
 
                Value::SInt16(v) => { *v = rhs.as_sint16(); },
 
                Value::SInt32(v) => { *v = rhs.as_sint32(); },
 
                Value::SInt64(v) => { *v = rhs.as_sint64(); },
 
                Value::Array(v) => { to_dealloc = Some(*v); *v = rhs.as_array(); },
 
                Value::Enum(v) => { *v = rhs.as_enum(); },
 
                Value::Union(lhs_tag, lhs_heap_pos) => {
 
                    to_dealloc = Some(*lhs_heap_pos);
 
                    let (rhs_tag, rhs_heap_pos) = rhs.as_union();
 
                    *lhs_tag = rhs_tag;
 
                    *lhs_heap_pos = rhs_heap_pos;
 
                }
 
                Value::Struct(v) => { to_dealloc = Some(*v); *v = rhs.as_struct(); },
 
                _ => unreachable!("apply_assignment_operator {:?} on lhs {:?} and rhs {:?}", op, lhs, rhs),
 
            }
 
        },
 
        AO::Multiplied =>   { apply_int_op!(lhs, *=,  op, rhs) },
 
        AO::Divided =>      { apply_int_op!(lhs, /=,  op, rhs) },
 
        AO::Remained =>     { apply_int_op!(lhs, %=,  op, rhs) },
 
        AO::Added =>        { apply_int_op!(lhs, +=,  op, rhs) },
 
        AO::Subtracted =>   { apply_int_op!(lhs, -=,  op, rhs) },
 
        AO::ShiftedLeft =>  { apply_int_op!(lhs, <<=, op, rhs) },
 
        AO::ShiftedRight => { apply_int_op!(lhs, >>=, op, rhs) },
 
        AO::BitwiseAnded => { apply_int_op!(lhs, &=,  op, rhs) },
 
        AO::BitwiseXored => { apply_int_op!(lhs, ^=,  op, rhs) },
 
        AO::BitwiseOred =>  { apply_int_op!(lhs, |=,  op, rhs) },
 
    }
 

	
 
    if let Some(heap_pos) = to_dealloc {
 
        store.drop_heap_pos(heap_pos);
 
    }
 
}
 

	
 
pub(crate) fn apply_binary_operator(store: &mut Store, lhs: &Value, op: BinaryOperator, rhs: &Value) -> Value {
 
    use BinaryOperator as BO;
 

	
 
    macro_rules! apply_int_op_and_return_self {
 
        ($lhs:ident, $operator_tokens:tt, $operator:ident, $rhs:ident) => {
 
            return match $lhs {
 
                Value::UInt8(v)  => { Value::UInt8( *v $operator_tokens $rhs.as_uint8() ) },
 
                Value::UInt16(v) => { Value::UInt16(*v $operator_tokens $rhs.as_uint16()) },
 
                Value::UInt32(v) => { Value::UInt32(*v $operator_tokens $rhs.as_uint32()) },
 
                Value::UInt64(v) => { Value::UInt64(*v $operator_tokens $rhs.as_uint64()) },
 
                Value::SInt8(v)  => { Value::SInt8( *v $operator_tokens $rhs.as_sint8() ) },
 
                Value::SInt16(v) => { Value::SInt16(*v $operator_tokens $rhs.as_sint16()) },
 
                Value::SInt32(v) => { Value::SInt32(*v $operator_tokens $rhs.as_sint32()) },
 
                Value::SInt64(v) => { Value::SInt64(*v $operator_tokens $rhs.as_sint64()) },
 
                _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs)
 
            };
 
        }
 
    }
 

	
 
    macro_rules! apply_int_op_and_return_bool {
 
        ($lhs:ident, $operator_tokens:tt, $operator:ident, $rhs:ident) => {
 
            return match $lhs {
 
                Value::UInt8(v)  => { Value::Bool(*v $operator_tokens $rhs.as_uint8() ) },
 
                Value::UInt16(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint16()) },
 
                Value::UInt32(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint32()) },
 
                Value::UInt64(v) => { Value::Bool(*v $operator_tokens $rhs.as_uint64()) },
 
                Value::SInt8(v)  => { Value::Bool(*v $operator_tokens $rhs.as_sint8() ) },
 
                Value::SInt16(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint16()) },
 
                Value::SInt32(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint32()) },
 
                Value::SInt64(v) => { Value::Bool(*v $operator_tokens $rhs.as_sint64()) },
 
                _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", $operator, $lhs, $rhs)
 
            };
 
        }
 
    }
 

	
 
    // We need to handle concatenate in a special way because it needs the store
 
    // mutably.
 
    if op == BO::Concatenate {
 
        let target_heap_pos = store.alloc_heap();
 
        let lhs_heap_pos;
 
        let rhs_heap_pos;
 

	
 
        let lhs = store.maybe_read_ref(lhs);
 
        let rhs = store.maybe_read_ref(rhs);
 

	
 
        enum ValueKind { Message, String, Array }
 
        let value_kind;
 

	
 
        match lhs {
 
            Value::Message(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_message();
 
                value_kind = ValueKind::Message;
 
            },
 
            Value::String(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_string();
 
                value_kind = ValueKind::String;
 
            },
 
            Value::Array(lhs_pos) => {
 
                lhs_heap_pos = *lhs_pos;
 
                rhs_heap_pos = rhs.as_array();
 
                value_kind = ValueKind::Array;
 
            },
 
            _ => unreachable!("apply_binary_operator {:?} on lhs {:?} and rhs {:?}", op, lhs, rhs)
 
        }
 

	
 
        let lhs_heap_pos = lhs_heap_pos as usize;
 
        let rhs_heap_pos = rhs_heap_pos as usize;
 

	
 
        // TODO: I hate this, but fine...
 
        let mut concatenated = Vec::new();
 
        let lhs_len = store.heap_regions[lhs_heap_pos].values.len();
 
        let rhs_len = store.heap_regions[rhs_heap_pos].values.len();
 
        concatenated.reserve(lhs_len + rhs_len);
 
        for idx in 0..lhs_len {
 
            concatenated.push(store.clone_value(store.heap_regions[lhs_heap_pos].values[idx].clone()));
 
        }
 
        for idx in 0..rhs_len {
 
            concatenated.push(store.clone_value(store.heap_regions[rhs_heap_pos].values[idx].clone()));
 
        }
 

	
 
        store.heap_regions[target_heap_pos as usize].values = concatenated;
 

	
 
        return match value_kind{
 
            ValueKind::Message => Value::Message(target_heap_pos),
 
            ValueKind::String => Value::String(target_heap_pos),
 
            ValueKind::Array => Value::Array(target_heap_pos),
 
        };
 
    }
 

	
 
    // If any of the values are references, retrieve the thing they're referring
 
    // to.
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    match op {
 
        BO::Concatenate => unreachable!(),
 
        BO::LogicalOr => {
 
            return Value::Bool(lhs.as_bool() || rhs.as_bool());
 
        },
 
        BO::LogicalAnd => {
 
            return Value::Bool(lhs.as_bool() && rhs.as_bool());
 
        },
 
        BO::BitwiseOr        => { apply_int_op_and_return_self!(lhs, |,  op, rhs); },
 
        BO::BitwiseXor       => { apply_int_op_and_return_self!(lhs, ^,  op, rhs); },
 
        BO::BitwiseAnd       => { apply_int_op_and_return_self!(lhs, &,  op, rhs); },
 
        BO::Equality         => { Value::Bool(apply_equality_operator(store, lhs, rhs)) },
 
        BO::Inequality       => { Value::Bool(apply_inequality_operator(store, lhs, rhs)) },
 
        BO::LessThan         => { apply_int_op_and_return_bool!(lhs, <,  op, rhs); },
 
        BO::GreaterThan      => { apply_int_op_and_return_bool!(lhs, >,  op, rhs); },
 
        BO::LessThanEqual    => { apply_int_op_and_return_bool!(lhs, <=, op, rhs); },
 
        BO::GreaterThanEqual => { apply_int_op_and_return_bool!(lhs, >=, op, rhs); },
 
        BO::ShiftLeft        => { apply_int_op_and_return_self!(lhs, <<, op, rhs); },
 
        BO::ShiftRight       => { apply_int_op_and_return_self!(lhs, >>, op, rhs); },
 
        BO::Add              => { apply_int_op_and_return_self!(lhs, +,  op, rhs); },
 
        BO::Subtract         => { apply_int_op_and_return_self!(lhs, -,  op, rhs); },
 
        BO::Multiply         => { apply_int_op_and_return_self!(lhs, *,  op, rhs); },
 
        BO::Divide           => { apply_int_op_and_return_self!(lhs, /,  op, rhs); },
 
        BO::Remainder        => { apply_int_op_and_return_self!(lhs, %,  op, rhs); }
 
    }
 
}
 

	
 
pub(crate) fn apply_unary_operator(store: &mut Store, op: UnaryOperator, value: &Value) -> Value {
 
    use UnaryOperator as UO;
 

	
 
    macro_rules! apply_int_expr_and_return {
 
        ($value:ident, $apply:tt, $op:ident) => {
 
            return match $value {
 
                Value::UInt8(v)  => Value::UInt8($apply *v),
 
                Value::UInt16(v) => Value::UInt16($apply *v),
 
                Value::UInt32(v) => Value::UInt32($apply *v),
 
                Value::UInt64(v) => Value::UInt64($apply *v),
 
                Value::SInt8(v)  => Value::SInt8($apply *v),
 
                Value::SInt16(v) => Value::SInt16($apply *v),
 
                Value::SInt32(v) => Value::SInt32($apply *v),
 
                Value::SInt64(v) => Value::SInt64($apply *v),
 
                _ => unreachable!("apply_unary_operator {:?} on value {:?}", $op, $value),
 
            };
 
        }
 
    }
 

	
 
    // If the value is a reference, retrieve the thing it is referring to
 
    let value = store.maybe_read_ref(value);
 

	
 
    match op {
 
        UO::Positive => {
 
            debug_assert!(value.is_integer());
 
            return value.clone();
 
        },
 
        UO::Negative => {
 
            // TODO: Error on negating unsigned integers
 
            return match value {
 
                Value::SInt8(v) => Value::SInt8(-*v),
 
                Value::SInt16(v) => Value::SInt16(-*v),
 
                Value::SInt32(v) => Value::SInt32(-*v),
 
                Value::SInt64(v) => Value::SInt64(-*v),
 
                _ => unreachable!("apply_unary_operator {:?} on value {:?}", op, value),
 
            }
 
        },
 
        UO::BitwiseNot => { apply_int_expr_and_return!(value, !, op)},
 
        UO::LogicalNot => { return Value::Bool(!value.as_bool()); },
 
        UO::PreIncrement => { todo!("implement") },
 
        UO::PreDecrement => { todo!("implement") },
 
        UO::PostIncrement => { todo!("implement") },
 
        UO::PostDecrement => { todo!("implement") },
 
    }
 
}
 

	
 
pub(crate) fn apply_casting(store: &mut Store, output_type: &ConcreteType, subject: &Value) -> Value {
 
pub(crate) fn apply_casting(store: &mut Store, output_type: &ConcreteType, subject: &Value) -> Result<Value, String> {
 
    // To simplify the casting logic: if the output type is not a simple
 
    // integer/boolean/character, then the type checker made sure that the two
 
    // types must be equal, hence we can do a simple clone.
 
    use ConcreteTypePart as CTP;
 
    let part = &output_type.parts[0];
 
    if output_type.parts.len() > 1 || (
 
        part != CTP::Bool &&
 
        part != CTP::Character &&
 
        part != CTP::UInt8 && part != CTP::UInt16 && part != CTP::UInt32 && part != CTP::UInt64 &&
 
        part != CTP::SInt8 && part != CTP::SInt16 && part != CTP::SInt32 && part != CTP::SInt64
 
    ) {
 
        // Complex thingamajig
 
        return store.clone_value(subject.clone());
 
    match part {
 
        CTP::Bool | CTP::Character |
 
        CTP::UInt8 | CTP::UInt16 | CTP::UInt32 | CTP::UInt64 |
 
        CTP::SInt8 | CTP::SInt16 | CTP::SInt32 | CTP::SInt64 => {
 
            // Do the checking of these below
 
            debug_assert_eq!(output_type.parts.len(), 1);
 
        },
 
        _ => {
 
            return Ok(store.clone_value(subject.clone()));
 
        },
 
    }
 

	
 
    // Note: character is not included, needs per-type checking
 
    macro_rules! unchecked_cast {
 
        ($input: expr, $output_part: expr) => {
 
            match $output_part {
 
                CTP::Bool => Value::Bool($input as bool),
 
                CTP::Character => Value::Char($input as char),
 
            return Ok(match $output_part {
 
                CTP::UInt8 => Value::UInt8($input as u8),
 
                CTP::UInt16 => Value::UInt16($input as u16),
 
                CTP::UInt32 => Value::UInt32($input as u32),
 
                CTP::UInt64 => Value::UInt64($input as u64),
 
                CTP::SInt8 => Value::SInt8($input as i8),
 
                CTP::SInt16 => Value::SInt16($input as i16),
 
                CTP::SInt32 => Value::SInt32($input as i32),
 
                CTP::SInt64 => Value::SInt64($input as i64),
 
                _ => unreachable!()
 
            }
 
            })
 
        }
 
    };
 

	
 
    macro_rules! from_unsigned_cast {
 
        ($input:expr, $input_type:ty, $output_part:expr) => {
 
            {
 
                let target_type_name = match $output_part {
 
                    CTP::Bool => return Ok(Value::Bool($input != 0)),
 
                    CTP::Character => if $input <= u8::MAX as $input_type {
 
                        return Ok(Value::Char(($input as u8) as char))
 
                    } else {
 
                        KW_TYPE_CHAR_STR
 
                    },
 
                    CTP::UInt8 => if $input <= u8::MAX as $input_type {
 
                        return Ok(Value::UInt8($input as u8))
 
                    } else {
 
                        KW_TYPE_UINT8_STR
 
                    },
 
                    CTP::UInt16 => if $input <= u16::MAX as $input_type {
 
                        return Ok(Value::UInt16($input as u16))
 
                    } else {
 
                        KW_TYPE_UINT16_STR
 
                    },
 
                    CTP::UInt32 => if $input <= u32::MAX as $input_type {
 
                        return Ok(Value::UInt32($input as u32))
 
                    } else {
 
                        KW_TYPE_UINT32_STR
 
                    },
 
                    CTP::UInt64 => return Ok(Value::UInt64($input as u64)), // any unsigned int to u64 is fine
 
                    CTP::SInt8 => if $input <= i8::MAX as $input_type {
 
                        return Ok(Value::SInt8($input as i8))
 
                    } else {
 
                        KW_TYPE_SINT8_STR
 
                    },
 
                    CTP::SInt16 => if $input <= i16::MAX as $input_type {
 
                        return Ok(Value::SInt16($input as i16))
 
                    } else {
 
                        KW_TYPE_SINT16_STR
 
                    },
 
                    CTP::SInt32 => if $input <= i32::MAX as $input_type {
 
                        return Ok(Value::SInt32($input as i32))
 
                    } else {
 
                        KW_TYPE_SINT32_STR
 
                    },
 
                    CTP::SInt64 => if $input <= i64::MAX as $input_type {
 
                        return Ok(Value::SInt64($input as i64))
 
                    } else {
 
                        KW_TYPE_SINT64_STR
 
                    },
 
                    _ => unreachable!(),
 
                };
 

	
 
                return Err(format!("value is '{}' which doesn't fit in a type '{}'", $input, target_type_name));
 
            }
 
        }
 
    }
 

	
 
    macro_rules! from_signed_cast {
 
        // Programmer note: for signed checking we cannot do
 
        //  output_type::MAX as input_type,
 
        //
 
        // because if the output type's width is larger than the input type,
 
        // then the cast results in a negative number. So we mask with the
 
        // maximum possible value the input type can become. As in:
 
        //  (output_type::MAX as input_type) & input_type::MAX
 
        //
 
        // This way:
 
        // 1. output width is larger than input width: fine in all cases, we
 
        //  simply compare against the max input value, which is always true.
 
        // 2. output width is equal to input width: by masking we "remove the
 
        //  signed bit from the unsigned number" and again compare against the
 
        //  maximum input value.
 
        // 3. output width is smaller than the input width: masking does nothing
 
        //  because the signed bit is never set, and we simply compare against
 
        //  the maximum possible output value.
 
        //
 
        // A similar kind of mechanism for the minimum value, but here we do
 
        // a binary OR. We do a:
 
        //  (output_type::MIN as input_type) & input_type::MIN
 
        //
 
        // This way:
 
        // 1. output width is larger than input width: initial cast truncates to
 
        //  0, then we OR with the actual minimum value, so we attain the
 
        //  minimum value of the input type.
 
        // 2. output width is equal to input width: we OR the minimum value with
 
        //  itself.
 
        // 3. output width is smaller than input width: the cast produces the
 
        //  min value of the output type, the subsequent OR does nothing, as it
 
        //  essentially just sets the signed bit (which must already be set,
 
        //  since we're dealing with a signed minimum value)
 
        //
 
        // After all of this expanding, we simply hope the compiler does a best
 
        // effort constant expression evaluation, and presto!
 
        ($input:expr, $input_type:ty, $output_type:expr) => {
 
            {
 
                let target_type_name = match $output_type {
 
                    CTP::Bool => return Ok(Value::Bool($input != 0)),
 
                    CTP::Character => if $input >= 0 && $input <= (u8::max as $input_type & <$input_type>::MAX) {
 
                        return Ok(Value::Char(($input as u8) as char))
 
                    } else {
 
                        KW_TYPE_CHAR_STR
 
                    },
 
                    CTP::UInt8 => if $input >= 0 && $input <= ((u8::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt8($input as u8));
 
                    } else {
 
                        KW_TYPE_UINT8_STR
 
                    },
 
                    CTP::UInt16 => if $input >= 0 && $input <= ((u16::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt16($input as u16));
 
                    } else {
 
                        KW_TYPE_UINT16_STR
 
                    },
 
                    CTP::UInt32 => if $input >= 0 && $input <= ((u32::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt32($input as u32));
 
                    } else {
 
                        KW_TYPE_UINT32_STR
 
                    },
 
                    CTP::UInt64 => if $input >= 0 && $input <= ((u64::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::UInt64($input as u64));
 
                    } else {
 
                        KW_TYPE_UINT64_STR
 
                    },
 
                    CTP::SInt8 => if $input >= ((i8::MIN as $input_type) | <$input_type>::MIN) && $input <= ((i8::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt8($input as i8));
 
                    } else {
 
                        KW_TYPE_SINT8_STR
 
                    },
 
                    CTP::SInt16 => if $input >= ((i16::MIN as $input_type | <$input_type>::MIN)) && $input <= ((i16::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt16($input as i16));
 
                    } else {
 
                        KW_TYPE_SINT16_STR
 
                    },
 
                    CTP::SInt32 => if $input >= ((i32::MIN as $input_type | <$input_type>::MIN)) && $input <= ((i32::MAX as $input_type) & <$input_type>::MAX) {
 
                        return Ok(Value::SInt32($input as i32));
 
                    } else {
 
                        KW_TYPE_SINT32_STR
 
                    },
 
                    CTP::SInt64 => return Ok(Value::SInt64($input as i64)),
 
                    _ => unreachable!(),
 
                };
 

	
 
                return Err(format!("value is '{}' which doesn't fit in a type '{}'", $input, target_type_name));
 
            }
 
        }
 
    }
 

	
 
    // If here, then the types might still be equal, but at least we're dealing
 
    // with a simple integer/boolean/character input and output type.
 
    let subject = store.maybe_read_ref(subject);
 
    match subject {
 
        Value::Bool(val) => unchecked_cast!(*val, part),
 
        Value::Char(val) => unchecked_cast!(*val, part),
 
        Value::UInt8(val) => {},
 
        Value::UInt16(val) => {},
 
        Value::UInt32(val) => {},
 
        Value::UInt64(val) => {},
 
        Value::SInt8(val) => {},
 
        Value::SInt16(val) => {},
 
        Value::SInt32(val) => {},
 
        Value::SInt64(val) => {},
 
        Value::Bool(val) => {
 
            match part {
 
                CTP::Bool => return Ok(Value::Bool(*val)),
 
                CTP::Character => return Ok(Value::Char(1 as char)),
 
                _ => unchecked_cast!(*val, part),
 
            }
 
        },
 
        Value::Char(val) => {
 
            match part {
 
                CTP::Bool => return Ok(Value::Bool(*val != 0 as char)),
 
                CTP::Character => return Ok(Value::Char(*val)),
 
                _ => unchecked_cast!(*val, part),
 
            }
 
        },
 
        Value::UInt8(val) => from_unsigned_cast!(*val, u8, part),
 
        Value::UInt16(val) => from_unsigned_cast!(*val, u16, part),
 
        Value::UInt32(val) => from_unsigned_cast!(*val, u32, part),
 
        Value::UInt64(val) => from_unsigned_cast!(*val, u64, part),
 
        Value::SInt8(val) => from_signed_cast!(*val, i8, part),
 
        Value::SInt16(val) => from_signed_cast!(*val, i16, part),
 
        Value::SInt32(val) => from_signed_cast!(*val, i32, part),
 
        Value::SInt64(val) => from_signed_cast!(*val, i64, part),
 
        _ => unreachable!("mismatch between 'cast' type checking and 'cast' evaluation"),
 
    }
 
}
 

	
 
pub(crate) fn apply_equality_operator(store: &Store, lhs: &Value, rhs: &Value) -> bool {
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    fn eval_equality_heap(store: &Store, lhs_pos: HeapPos, rhs_pos: HeapPos) -> bool {
 
        let lhs_vals = &store.heap_regions[lhs_pos as usize].values;
 
        let rhs_vals = &store.heap_regions[rhs_pos as usize].values;
 
        let lhs_len = lhs_vals.len();
 
        if lhs_len != rhs_vals.len() {
 
            return false;
 
        }
 

	
 
        for idx in 0..lhs_len {
 
            let lhs_val = &lhs_vals[idx];
 
            let rhs_val = &rhs_vals[idx];
 
            if !apply_equality_operator(store, lhs_val, rhs_val) {
 
                return false;
 
            }
 
        }
 

	
 
        return true;
 
    }
 

	
 
    match lhs {
 
        Value::Input(v) => *v == rhs.as_input(),
 
        Value::Output(v) => *v == rhs.as_output(),
 
        Value::Message(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_message()),
 
        Value::Null => todo!("remove null"),
 
        Value::Bool(v) => *v == rhs.as_bool(),
 
        Value::Char(v) => *v == rhs.as_char(),
 
        Value::String(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_string()),
 
        Value::UInt8(v) => *v == rhs.as_uint8(),
 
        Value::UInt16(v) => *v == rhs.as_uint16(),
 
        Value::UInt32(v) => *v == rhs.as_uint32(),
 
        Value::UInt64(v) => *v == rhs.as_uint64(),
 
        Value::SInt8(v) => *v == rhs.as_sint8(),
 
        Value::SInt16(v) => *v == rhs.as_sint16(),
 
        Value::SInt32(v) => *v == rhs.as_sint32(),
 
        Value::SInt64(v) => *v == rhs.as_sint64(),
 
        Value::Array(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_array()),
 
        Value::Enum(v) => *v == rhs.as_enum(),
 
        Value::Union(lhs_tag, lhs_pos) => {
 
            let (rhs_tag, rhs_pos) = rhs.as_union();
 
            if *lhs_tag != rhs_tag {
 
                return false;
 
            }
 
            eval_equality_heap(store, *lhs_pos, rhs_pos)
 
        },
 
        Value::Struct(lhs_pos) => eval_equality_heap(store, *lhs_pos, rhs.as_struct()),
 
        _ => unreachable!("apply_equality_operator to lhs {:?}", lhs),
 
    }
 
}
 

	
 
pub(crate) fn apply_inequality_operator(store: &Store, lhs: &Value, rhs: &Value) -> bool {
 
    let lhs = store.maybe_read_ref(lhs);
 
    let rhs = store.maybe_read_ref(rhs);
 

	
 
    fn eval_inequality_heap(store: &Store, lhs_pos: HeapPos, rhs_pos: HeapPos) -> bool {
 
        let lhs_vals = &store.heap_regions[lhs_pos as usize].values;
 
        let rhs_vals = &store.heap_regions[rhs_pos as usize].values;
 
        let lhs_len = lhs_vals.len();
 
        if lhs_len != rhs_vals.len() {
 
            return true;
 
        }
 

	
 
        for idx in 0..lhs_len {
 
            let lhs_val = &lhs_vals[idx];
 
            let rhs_val = &rhs_vals[idx];
 
            if apply_inequality_operator(store, lhs_val, rhs_val) {
 
                return true;
 
            }
 
        }
 

	
 
        return false;
 
    }
 

	
 
    match lhs {
 
        Value::Input(v) => *v != rhs.as_input(),
 
        Value::Output(v) => *v != rhs.as_output(),
 
        Value::Message(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_message()),
 
        Value::Null => todo!("remove null"),
 
        Value::Bool(v) => *v != rhs.as_bool(),
 
        Value::Char(v) => *v != rhs.as_char(),
 
        Value::String(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_string()),
 
        Value::UInt8(v) => *v != rhs.as_uint8(),
 
        Value::UInt16(v) => *v != rhs.as_uint16(),
 
        Value::UInt32(v) => *v != rhs.as_uint32(),
 
        Value::UInt64(v) => *v != rhs.as_uint64(),
 
        Value::SInt8(v) => *v != rhs.as_sint8(),
 
        Value::SInt16(v) => *v != rhs.as_sint16(),
 
        Value::SInt32(v) => *v != rhs.as_sint32(),
 
        Value::SInt64(v) => *v != rhs.as_sint64(),
 
        Value::Enum(v) => *v != rhs.as_enum(),
 
        Value::Union(lhs_tag, lhs_pos) => {
 
            let (rhs_tag, rhs_pos) = rhs.as_union();
 
            if *lhs_tag != rhs_tag {
 
                return true;
 
            }
 
            eval_inequality_heap(store, *lhs_pos, rhs_pos)
 
        },
 
        Value::String(lhs_pos) => eval_inequality_heap(store, *lhs_pos, rhs.as_struct()),
 
        _ => unreachable!("apply_inequality_operator to lhs {:?}", lhs)
 
    }
 
}
 
\ No newline at end of file
src/protocol/parser/pass_definitions.rs
Show inline comments
 
use crate::protocol::ast::*;
 
use super::symbol_table::*;
 
use super::{Module, ModuleCompilationPhase, PassCtx};
 
use super::tokens::*;
 
use super::token_parsing::*;
 
use crate::protocol::input_source::{InputSource as InputSource, InputPosition as InputPosition, InputSpan, ParseError};
 
use crate::collections::*;
 

	
 
/// Parses all the tokenized definitions into actual AST nodes.
 
pub(crate) struct PassDefinitions {
 
    // State associated with the definition currently being processed
 
    cur_definition: DefinitionId,
 
    // Temporary buffers of various kinds
 
    buffer: String,
 
    struct_fields: ScopedBuffer<StructFieldDefinition>,
 
    enum_variants: ScopedBuffer<EnumVariantDefinition>,
 
    union_variants: ScopedBuffer<UnionVariantDefinition>,
 
    variables: ScopedBuffer<VariableId>,
 
    expressions: ScopedBuffer<ExpressionId>,
 
    statements: ScopedBuffer<StatementId>,
 
    parser_types: ScopedBuffer<ParserType>,
 
}
 

	
 
impl PassDefinitions {
 
    pub(crate) fn new() -> Self {
 
        Self{
 
            cur_definition: DefinitionId::new_invalid(),
 
            buffer: String::with_capacity(128),
 
            struct_fields: ScopedBuffer::new_reserved(128),
 
            enum_variants: ScopedBuffer::new_reserved(128),
 
            union_variants: ScopedBuffer::new_reserved(128),
 
            variables: ScopedBuffer::new_reserved(128),
 
            expressions: ScopedBuffer::new_reserved(128),
 
            statements: ScopedBuffer::new_reserved(128),
 
            parser_types: ScopedBuffer::new_reserved(128),
 
        }
 
    }
 

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

	
 
        // Although we only need to parse the definitions, we want to go through
 
        // code ranges as well such that we can throw errors if we get
 
        // unexpected tokens at the module level of the source.
 
        let mut range_idx = module_range.first_child_idx;
 
        loop {
 
            let range_idx_usize = range_idx as usize;
 
            let cur_range = &module.tokens.ranges[range_idx_usize];
 

	
 
            match cur_range.range_kind {
 
                TokenRangeKind::Module => unreachable!(), // should not be reachable
 
                TokenRangeKind::Pragma | TokenRangeKind::Import => {
 
                    // Already fully parsed, fall through and go to next range
 
                },
 
                TokenRangeKind::Definition | TokenRangeKind::Code => {
 
                    // Visit range even if it is a "code" range to provide
 
                    // proper error messages.
 
                    self.visit_range(modules, module_idx, ctx, range_idx_usize)?;
 
                },
 
            }
 

	
 
            if cur_range.next_sibling_idx == NO_SIBLING {
 
                break;
 
            } else {
 
                range_idx = cur_range.next_sibling_idx;
 
            }
 
        }
 

	
 
        modules[module_idx].phase = ModuleCompilationPhase::DefinitionsParsed;
 

	
 
        Ok(())
 
    }
 

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

	
 
        // Detect which definition we're parsing
 
        let mut iter = module.tokens.iter_range(cur_range);
 
        loop {
 
            let next = iter.next();
 
            if next.is_none() {
 
                return Ok(())
 
            }
 

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

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

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

	
 
        // Parse struct definition
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        let mut fields_section = self.struct_fields.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 

	
 
                let start_pos = iter.last_valid_pos();
 
                let parser_type = consume_parser_type(
 
                    source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope,
 
                    definition_id, false, 0
 
                )?;
 
                let field = consume_ident_interned(source, iter, ctx)?;
 
                Ok(StructFieldDefinition{
 
                    span: InputSpan::from_positions(start_pos, field.span.end),
 
                    field, parser_type
 
                })
 
            },
 
            &mut fields_section, "a struct field", "a list of struct fields", None
 
        )?;
 

	
 
        // Transfer to preallocated definition
 
        let struct_def = ctx.heap[definition_id].as_struct_mut();
 
        struct_def.fields = fields_section.into_vec();
 

	
 
        Ok(())
 
    }
 

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

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

	
 
        // Parse enum definition
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

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

	
 
        // Transfer to definition
 
        let enum_def = ctx.heap[definition_id].as_enum_mut();
 
        enum_def.variants = enum_section.into_vec();
 

	
 
        Ok(())
 
    }
 

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

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

	
 
        // Parse union definition
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

	
 
        let mut variants_section = self.union_variants.start_section();
 
        consume_comma_separated(
 
            TokenKind::OpenCurly, TokenKind::CloseCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let identifier = consume_ident_interned(source, iter, ctx)?;
 
                let mut close_pos = identifier.span.end;
 

	
 
                let mut types_section = self.parser_types.start_section();
 

	
 
                let has_embedded = maybe_consume_comma_separated(
 
                    TokenKind::OpenParen, TokenKind::CloseParen, source, iter, ctx,
 
                    |source, iter, ctx| {
 
                        let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 
                        consume_parser_type(
 
                            source, iter, &ctx.symbols, &ctx.heap, poly_vars,
 
                            module_scope, definition_id, false, 0
 
                        )
 
                    },
 
                    &mut types_section, "an embedded type", Some(&mut close_pos)
 
                )?;
 
                let value = if has_embedded {
 
                    UnionVariantValue::Embedded(types_section.into_vec())
 
                } else {
 
                    types_section.forget();
 
                    UnionVariantValue::None
 
                };
 

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

	
 
        // Transfer to AST
 
        let union_def = ctx.heap[definition_id].as_union_mut();
 
        union_def.variants = variants_section.into_vec();
 

	
 
        Ok(())
 
    }
 

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

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

	
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

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

	
 
        // Consume return types
 
        consume_token(&module.source, iter, TokenKind::ArrowRight)?;
 
        let mut return_types = self.parser_types.start_section();
 
        let mut open_curly_pos = iter.last_valid_pos(); // bogus value
 
        consume_comma_separated_until(
 
            TokenKind::OpenCurly, &module.source, iter, ctx,
 
            |source, iter, ctx| {
 
                let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 
                consume_parser_type(source, iter, &ctx.symbols, &ctx.heap, poly_vars, module_scope, definition_id, false, 0)
 
            },
 
            &mut return_types, "a return type", Some(&mut open_curly_pos)
 
        )?;
 
        let return_types = return_types.into_vec();
 

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

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

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

	
 
        Ok(())
 
    }
 

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

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

	
 
        consume_polymorphic_vars_spilled(&module.source, iter, ctx)?;
 

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

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

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

	
 
        Ok(())
 
    }
 

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

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

	
 
            let id = ctx.heap.alloc_block_statement(|this| BlockStatement{
 
                this,
 
                is_implicit: true,
 
                span: InputSpan::from_positions(wrap_begin_pos, wrap_end_pos), // TODO: @Span
 
                statements,
 
                end_block: EndBlockStatementId::new_invalid(),
 
                parent_scope: Scope::Definition(DefinitionId::new_invalid()),
 
                first_unique_id_in_scope: -1,
 
                next_unique_id_in_scope: -1,
 
                relative_pos_in_parent: 0,
 
                locals: Vec::new(),
 
                labels: Vec::new()
 
            });
 

	
 
            let end_block = ctx.heap.alloc_end_block_statement(|this| EndBlockStatement{
 
                this, start_block: id, next: StatementId::new_invalid()
 
            });
 

	
 
            let block_stmt = &mut ctx.heap[id];
 
            block_stmt.end_block = end_block;
 

	
 
            Ok(id)
 
        }
 
    }
 

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

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

	
 
                let end_if = ctx.heap.alloc_end_if_statement(|this| EndIfStatement{
 
                    this, start_if: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_if.upcast());
 

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

	
 
                let end_while = ctx.heap.alloc_end_while_statement(|this| EndWhileStatement{
 
                    this, start_while: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_while.upcast());
 

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

	
 
                let end_sync = ctx.heap.alloc_end_synchronous_statement(|this| EndSynchronousStatement{
 
                    this, start_sync: id, next: StatementId::new_invalid()
 
                });
 
                section.push(end_sync.upcast());
 

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

	
 
        return Ok(());
 
    }
 

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

	
 
    fn consume_block_statement_without_leading_curly(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx, open_curly_pos: InputPosition
 
    ) -> Result<BlockStatementId, ParseError> {
 
        let mut stmt_section = self.statements.start_section();
 
        let mut next = iter.next();
 
        while next != Some(TokenKind::CloseCurly) {
 
            if next.is_none() {
 
                return Err(ParseError::new_error_str_at_pos(
 
                    &module.source, iter.last_valid_pos(), "expected a statement or '}'"
 
                ));
 
            }
 
            self.consume_statement(module, iter, ctx, &mut stmt_section)?;
 
            next = iter.next();
 
        }
 

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

	
 
        let id = ctx.heap.alloc_block_statement(|this| BlockStatement{
 
            this,
 
            is_implicit: false,
 
            span: block_span,
 
            statements,
 
            end_block: EndBlockStatementId::new_invalid(),
 
            parent_scope: Scope::Definition(DefinitionId::new_invalid()),
 
            first_unique_id_in_scope: -1,
 
            next_unique_id_in_scope: -1,
 
            relative_pos_in_parent: 0,
 
            locals: Vec::new(),
 
            labels: Vec::new(),
 
        });
 

	
 
        let end_block = ctx.heap.alloc_end_block_statement(|this| EndBlockStatement{
 
            this, start_block: id, next: StatementId::new_invalid()
 
        });
 

	
 
        let block_stmt = &mut ctx.heap[id];
 
        block_stmt.end_block = end_block;
 

	
 
        Ok(id)
 
    }
 

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

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

	
 
        Ok(ctx.heap.alloc_if_statement(|this| IfStatement{
 
            this,
 
            span: if_span,
 
            test,
 
            true_body,
 
            false_body,
 
            end_if: EndIfStatementId::new_invalid(),
 
        }))
 
    }
 

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

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

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

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

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

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

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

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

	
 
        if expressions.is_empty() {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "expected at least one return value"));
 
        } else if expressions.len() > 1 {
 
            return Err(ParseError::new_error_str_at_span(&module.source, return_span, "multiple return values are not (yet) supported"))
 
        }
 

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

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

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

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

	
 
        let mut call_id = CallExpressionId::new_invalid();
 
        if let Expression::Call(expression) = expression {
 
            // Allow both components and functions, as it makes more sense to
 
            // check their correct use in the validation and linking pass
 
            if expression.method == Method::UserComponent || expression.method == Method::UserFunction {
 
                call_id = expression.this;
 
                valid = true;
 
            }
 
        }
 

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

	
 
        debug_assert!(!call_id.is_invalid());
 
        Ok(ctx.heap.alloc_new_statement(|this| NewStatement{
 
            this,
 
            span: new_span,
 
            expression: call_id,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

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

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

	
 
        // Construct ports
 
        let from = ctx.heap.alloc_variable(|this| Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: from_identifier,
 
            parser_type: channel_type.clone(),
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: -1,
 
        });
 
        let to = ctx.heap.alloc_variable(|this|Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: to_identifier,
 
            parser_type: channel_type,
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: -1,
 
        });
 

	
 
        // Construct the channel
 
        Ok(ctx.heap.alloc_channel_statement(|this| ChannelStatement{
 
            this,
 
            span: channel_span,
 
            from, to,
 
            relative_pos_in_block: 0,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

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

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

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

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

	
 
        Ok(())
 
    }
 

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

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

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

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

	
 
                // Allocate the memory statement with the variable
 
                let local_id = ctx.heap.alloc_variable(|this| Variable{
 
                    this,
 
                    kind: VariableKind::Local,
 
                    identifier: identifier.clone(),
 
                    parser_type,
 
                    relative_pos_in_block: 0,
 
                    unique_id_in_scope: -1,
 
                });
 
                let memory_stmt_id = ctx.heap.alloc_memory_statement(|this| MemoryStatement{
 
                    this,
 
                    span: memory_span,
 
                    variable: local_id,
 
                    next: StatementId::new_invalid()
 
                });
 

	
 
                // Allocate the initial assignment
 
                let variable_expr_id = ctx.heap.alloc_variable_expression(|this| VariableExpression{
 
                    this,
 
                    identifier,
 
                    declaration: None,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 
                let assignment_expr_id = ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                    this,
 
                    span: assign_span,
 
                    left: variable_expr_id.upcast(),
 
                    operation: AssignmentOperator::Set,
 
                    right: initial_expr_id,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 
                let assignment_stmt_id = ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
                    this,
 
                    span: InputSpan::from_positions(initial_expr_begin_pos, initial_expr_end_pos),
 
                    expression: assignment_expr_id.upcast(),
 
                    next: StatementId::new_invalid(),
 
                });
 

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

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

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

	
 
        Ok(ctx.heap.alloc_expression_statement(|this| ExpressionStatement{
 
            this,
 
            span: InputSpan::from_positions(start_pos, end_pos),
 
            expression,
 
            next: StatementId::new_invalid(),
 
        }))
 
    }
 

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

	
 
    // TODO: @Cleanup This is fine for now. But I prefer my stacktraces not to
 
    //  look like enterprise Java code...
 
    fn consume_expression(
 
        &mut self, module: &Module, iter: &mut TokenIter, ctx: &mut PassCtx
 
    ) -> Result<ExpressionId, ParseError> {
 
        self.consume_assignment_expression(module, iter, ctx)
 
    }
 

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

	
 
            if token.is_none() {
 
                return None
 
            }
 

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

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

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

	
 
            Ok(ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else {
 
            Ok(expr)
 
        }
 
    }
 

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

	
 
            let test = result;
 
            let true_expression = self.consume_expression(module, iter, ctx)?;
 
            consume_token(&module.source, iter, TokenKind::Colon)?;
 
            let false_expression = self.consume_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_conditional_expression(|this| ConditionalExpression{
 
                this, span, test, true_expression, false_expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else {
 
            Ok(result)
 
        }
 
    }
 

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

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

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

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

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

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

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

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

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

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

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

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

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

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this, span, operation, expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else {
 
            self.consume_postfix_expression(module, iter, ctx)
 
        }
 
    }
 

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

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

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

	
 
            if token == TokenKind::PlusPlus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperator::PostIncrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                }).upcast();
 
            } else if token == TokenKind::MinusMinus {
 
                result = ctx.heap.alloc_unary_expression(|this| UnaryExpression{
 
                    this, span,
 
                    operation: UnaryOperator::PostDecrement,
 
                    expression: result,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                }).upcast();
 
            } else if token == TokenKind::OpenSquare {
 
                let subject = result;
 
                let from_index = self.consume_expression(module, iter, ctx)?;
 

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

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

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this, span, subject, from_index, to_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else if Some(TokenKind::CloseSquare) == next {
 
                    let end_span = consume_token(&module.source, iter, TokenKind::CloseSquare)?;
 
                    span.end = end_span.end;
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, span, subject,
 
                        index: from_index,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast();
 
                } else {
 
                    return Err(ParseError::new_error_str_at_pos(
 
                        &module.source, iter.last_valid_pos(), "unexpected token: expected ']' or '..'"
 
                    ));
 
                }
 
            } else {
 
                debug_assert_eq!(token, TokenKind::Dot);
 
                let subject = result;
 
                let field_name = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, span, subject, field_name,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                }).upcast();
 
            }
 

	
 
            next = iter.next();
 
        }
 

	
 
        Ok(result)
 
    }
 

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

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

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

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this,
 
                span: InputSpan::from_positions(start_pos, end_pos),
 
                value: Literal::Array(scoped_section.into_vec()),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Integer) {
 
            let (literal, span) = consume_integer_literal(&module.source, iter, &mut self.buffer)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Integer(LiteralInteger{ unsigned_value: literal, negated: false }),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::String) {
 
            let span = consume_string_literal(&module.source, iter, &mut self.buffer)?;
 
            let interned = ctx.pool.intern(self.buffer.as_bytes());
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::String(interned),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Character) {
 
            let (character, span) = consume_character_literal(&module.source, iter)?;
 

	
 
            ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                this, span,
 
                value: Literal::Character(character),
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast()
 
        } else if next == Some(TokenKind::Ident) {
 
            // May be a variable, a type instantiation or a function call. If we
 
            // have a single identifier that we cannot find in the type table
 
            // then we're going to assume that we're dealing with a variable.
 
            let ident_span = iter.next_span();
 
            let ident_text = module.source.section_at_span(ident_span);
 
            let symbol = ctx.symbols.get_symbol_by_name(SymbolScope::Module(module.root_id), ident_text);
 

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

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

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, last_token),
 
                                    value: Literal::Struct(LiteralStruct{
 
                                        parser_type,
 
                                        fields: struct_fields,
 
                                        definition: target_definition_id,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Enum(_) => {
 
                                // Enum literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, variant.span.end),
 
                                    value: Literal::Enum(LiteralEnum{
 
                                        parser_type,
 
                                        variant,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Union(_) => {
 
                                // Union literal: consume the variant
 
                                consume_token(&module.source, iter, TokenKind::ColonColon)?;
 
                                let variant = consume_ident_interned(&module.source, iter, ctx)?;
 

	
 
                                // Consume any possible embedded values
 
                                let mut end_pos = variant.span.end;
 
                                let values = if Some(TokenKind::OpenParen) == iter.next() {
 
                                    self.consume_expression_list(module, iter, ctx, Some(&mut end_pos))?
 
                                } else {
 
                                    Vec::new()
 
                                };
 

	
 
                                ctx.heap.alloc_literal_expression(|this| LiteralExpression{
 
                                    this,
 
                                    span: InputSpan::from_positions(ident_span.begin, end_pos),
 
                                    value: Literal::Union(LiteralUnion{
 
                                        parser_type, variant, values,
 
                                        definition: target_definition_id,
 
                                        variant_idx: 0,
 
                                    }),
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Component(_) => {
 
                                // Component instantiation
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method: Method::UserComponent,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            },
 
                            Definition::Function(function_definition) => {
 
                                // Check whether it is a builtin function
 
                                let method = if function_definition.builtin {
 
                                    match function_definition.identifier.value.as_str() {
 
                                        "get" => Method::Get,
 
                                        "put" => Method::Put,
 
                                        "fires" => Method::Fires,
 
                                        "create" => Method::Create,
 
                                        "length" => Method::Length,
 
                                        "assert" => Method::Assert,
 
                                        _ => unreachable!(),
 
                                    }
 
                                } else {
 
                                    Method::UserFunction
 
                                };
 

	
 
                                // Function call: consume the arguments
 
                                let arguments = self.consume_expression_list(module, iter, ctx, None)?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.elements[0].full_span, // TODO: @Span fix
 
                                    parser_type,
 
                                    method,
 
                                    arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            }
 
                        }
 
                    },
 
                    _ => {
 
                        // TODO: Casting expressions
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, parser_type.elements[0].full_span,
 
                            "unexpected type in expression, note that casting expressions are not yet implemented"
 
                        ))
 
                    }
 
                }
 
            } else {
 
                // Check for builtin keywords or builtin functions
 
                if ident_text == KW_LIT_NULL || ident_text == KW_LIT_TRUE || ident_text == KW_LIT_FALSE {
 
                    iter.consume();
 

	
 
                    // Parse builtin literal
 
                    let value = match ident_text {
 
                        KW_LIT_NULL => Literal::Null,
 
                        KW_LIT_TRUE => Literal::True,
 
                        KW_LIT_FALSE => Literal::False,
 
                        _ => unreachable!(),
 
                    };
 

	
 
                    ctx.heap.alloc_literal_expression(|this| LiteralExpression {
 
                        this,
 
                        span: ident_span,
 
                        value,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                } else if ident_text == KW_CAST {
 
                    // Casting expression
 
                    iter.consume();
 
                    let to_type = if Some(TokenKind::OpenAngle) == iter.next() {
 
                        iter.consume();
 
                        let definition_id = self.cur_definition;
 
                        let poly_vars = ctx.heap[definition_id].poly_vars();
 
                        consume_parser_type(
 
                            &module.source, iter, &ctx.symbols, &ctx.heap,
 
                            poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                            true, 1
 
                        )?
 
                    } else {
 
                        // Automatic casting with inferred target type
 
                        ParserType{ elements: vec![ParserTypeElement{
 
                            full_span: ident_span, // TODO: @Span fix
 
                            variant: ParserTypeVariant::Inferred,
 
                        }]}
 
                    };
 

	
 
                    consume_token(&module.source, iter, TokenKind::OpenParen)?;
 
                    let subject = self.consume_expression(module, iter, ctx)?;
 
                    consume_token(&module.source, iter, TokenKind::CloseParen)?;
 

	
 
                    ctx.heap.alloc_cast_expression(|this| CastExpression{
 
                        this,
 
                        span: ident_span,
 
                        to_type,
 
                        subject,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                } else {
 
                    // Not a builtin literal, but also not a known type. So we
 
                    // assume it is a variable expression. Although if we do,
 
                    // then if a programmer mistyped a struct/function name the
 
                    // error messages will be rather cryptic. For polymorphic
 
                    // arguments we can't really do anything at all (because it
 
                    // uses the '<' token). In the other cases we try to provide
 
                    // a better error message.
 
                    iter.consume();
 
                    let next = iter.next();
 
                    if Some(TokenKind::ColonColon) == next {
 
                        return Err(ParseError::new_error_str_at_span(&module.source, ident_span, "unknown identifier"));
 
                    } else if Some(TokenKind::OpenParen) == next {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, ident_span,
 
                            "unknown identifier, did you mistype a union variant's or a function's name?"
 
                        ));
 
                    } else if Some(TokenKind::OpenCurly) == next {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, ident_span,
 
                            "unknown identifier, did you mistype a struct type's name?"
 
                        ))
 
                    }
 

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

	
 
                    ctx.heap.alloc_variable_expression(|this| VariableExpression {
 
                        this,
 
                        identifier,
 
                        declaration: None,
 
                        parent: ExpressionParent::None,
 
                        unique_id_in_definition: -1,
 
                    }).upcast()
 
                }
 
            }
 
        } else {
 
            return Err(ParseError::new_error_str_at_pos(
 
                &module.source, iter.last_valid_pos(), "expected an expression"
 
            ));
 
        };
 

	
 
        Ok(result)
 
    }
 

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

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

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

	
 
            result = ctx.heap.alloc_binary_expression(|this| BinaryExpression{
 
                this, span, left, operation, right,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast();
 
        }
 

	
 
        Ok(result)
 
    }
 

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

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

	
 
    // After parsing the array modified "[]", we need to insert an array type
 
    // before the most recently parsed type.
 
    fn insert_array_before(elements: &mut Vec<Entry>, depth: i32, span: InputSpan) {
 
        let index = elements.iter().rposition(|e| e.depth == depth).unwrap();
 
        elements.insert(index, Entry{
 
            element: ParserTypeElement{ full_span: span, variant: ParserTypeVariant::Array },
 
            depth,
 
        });
 
    }
 

	
 
    // Most common case we just have one type, perhaps with some array
 
    // annotations. This is both the hot-path, and simplifies the state machine
 
    // that follows and is responsible for parsing more complicated types.
 
    let element = consume_parser_type_ident(source, iter, symbols, heap, poly_vars, cur_scope, wrapping_definition, allow_inference)?;
 
    if iter.next() != Some(TokenKind::OpenAngle) {
 
        let num_embedded = element.variant.num_embedded();
 
        let mut num_array = 0;
 
        while iter.next() == Some(TokenKind::OpenSquare) {
 
            iter.consume();
 
            consume_token(source, iter, TokenKind::CloseSquare)?;
 
            num_array += 1;
 
        }
 

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

	
 
        if num_embedded != 0 {
 
            if !allow_inference {
 
                return Err(ParseError::new_error_str_at_span(source, array_span, "type inference is not allowed here"));
 
            }
 

	
 
            for _ in 0..num_embedded {
 
                elements.push(ParserTypeElement { full_span: array_span, variant: ParserTypeVariant::Inferred });
 
            }
 
        }
 

	
 
        for _ in 0..first_angle_depth {
 
            consume_token(source, iter, TokenKind::CloseAngle);
 
        }
 

	
 
        return Ok(ParserType{ elements });
 
    };
 

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

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

	
 
    loop {
 
        let next = iter.next();
 

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

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

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

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

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

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

	
 
                // Insert the missing types
 
                let inserted_span = cur_element.element.full_span;
 
                let inserted_depth = cur_element.depth + 1;
 
                elements.reserve(expected_subtypes);
 
                for _ in 0..expected_subtypes {
 
                    elements.insert(idx + 1, Entry{
 
                        element: ParserTypeElement{ full_span: inserted_span, variant: ParserTypeVariant::Inferred },
 
                        depth: inserted_depth,
 
                    });
 
                }
 
            } else {
 
                // Mismatch in number of embedded types, produce a neat error
 
                // message.
 
                let type_name = String::from_utf8_lossy(source.section_at_span(cur_element.element.full_span));
 
                fn polymorphic_name_text(num: usize) -> &'static str {
 
                    if num == 1 { "polymorphic argument" } else { "polymorphic arguments" }
 
                }
 
                fn were_or_was(num: usize) -> &'static str {
 
                    if num == 1 { "was" } else { "were" }
 
                }
 

	
 
                if expected_subtypes == 0 {
 
                    return Err(ParseError::new_error_at_span(
 
                        source, cur_element.element.full_span,
 
                        format!(
 
                            "the type '{}' is not polymorphic, yet {} {} {} provided",
 
                            type_name, encountered_subtypes, polymorphic_name_text(encountered_subtypes),
 
                            were_or_was(encountered_subtypes)
 
                        )
 
                    ));
 
                }
 

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

	
 
                return Err(ParseError::new_error_at_span(
 
                    source, cur_element.element.full_span,
 
                    format!(
 
                        "expected {} {}{} for the type '{}', but {} {} provided",
 
                        expected_subtypes, polymorphic_name_text(expected_subtypes),
 
                        maybe_infer_text, type_name, encountered_subtypes,
 
                        were_or_was(encountered_subtypes)
 
                    )
 
                ));
 
            }
 
        }
 

	
 
        idx += 1;
 
    }
 

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

	
 
    Ok(ParserType{ elements: constructed_elements })
 
}
 

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

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

	
 
            PTV::Inferred
 
        },
 
        _ => {
 
            // Must be some kind of symbolic type
 
            let mut type_kind = None;
 
            for (poly_idx, poly_var) in poly_vars.iter().enumerate() {
 
                if poly_var.value.as_bytes() == type_text {
 
                    type_kind = Some(PTV::PolymorphicArgument(wrapping_definition, poly_idx as u32));
 
                }
 
            }
 

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

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

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

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

	
 
                            let new_symbol = symbols.get_symbol_by_name_defined_in_scope(scope, type_text);
 
                            if new_symbol.is_none() {
 
                                // If the type is imported in the module then notify the programmer
 
                                // that imports do not leak outside of a module
 
                                let type_name = String::from_utf8_lossy(type_text);
 
                                let module_name = String::from_utf8_lossy(old_text);
 
                                let suffix = if symbols.get_symbol_by_name(scope, type_text).is_some() {
 
                                    format!(
 
                                        ". The module '{}' does import '{}', but these imports are not visible to other modules",
 
                                        &module_name, &type_name
 
                                    )
 
                                } else {
 
                                    String::new()
 
                                };
 

	
 
                                return Err(ParseError::new_error_at_span(
 
                                    source, next_span,
 
                                    format!("unknown type '{}' in module '{}'{}", type_name, module_name, suffix)
 
                                ));
 
                            }
 

	
 
                            last_symbol = new_symbol.unwrap();
 
                        },
 
                        SymbolVariant::Definition(symbol_definition) => {
 
                            let num_poly_vars = heap[symbol_definition.definition_id].poly_vars().len();
 
                            type_kind = Some(PTV::Definition(symbol_definition.definition_id, num_poly_vars as u32));
 
                            break;
 
                        }
 
                    }
 
                }
 
            }
 

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

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

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

	
 
/// Consumes the parameter list to functions/components
 
fn consume_parameter_list(
 
    source: &InputSource, iter: &mut TokenIter, ctx: &mut PassCtx,
 
    target: &mut ScopedSection<VariableId>, scope: SymbolScope, definition_id: DefinitionId
 
) -> Result<(), ParseError> {
 
    consume_comma_separated(
 
        TokenKind::OpenParen, TokenKind::CloseParen, source, iter, ctx,
 
        |source, iter, ctx| {
 
            let poly_vars = ctx.heap[definition_id].poly_vars(); // TODO: @Cleanup, this is really ugly. But rust...
 
            let parser_type = consume_parser_type(
 
                source, iter, &ctx.symbols, &ctx.heap, poly_vars, scope,
 
                definition_id, false, 0
 
            )?;
 
            let identifier = consume_ident_interned(source, iter, ctx)?;
 
            let parameter_id = ctx.heap.alloc_variable(|this| Variable{
 
                this,
 
                kind: VariableKind::Parameter,
 
                parser_type,
 
                identifier,
 
                relative_pos_in_block: 0,
 
                unique_id_in_scope: -1,
 
            });
 
            Ok(parameter_id)
 
        },
 
        target, "a parameter", "a parameter list", None
 
    )
 
}
 
\ No newline at end of file
src/protocol/tests/eval_casting.rs
Show inline comments
 
new file 100644
 
use super::*;
 

	
 
#[test]
 
fn test_valid_unsigned_casting() {
 
    Tester::new_single_source_expect_ok("cast u8", "
 
        func foo() -> bool {
 
            u64 large_width = 255;
 
            u8 small_width = 255;
 

	
 
            // Explicit casting
 
            auto large_exp_to_08 = cast<u8> (large_width);
 
            auto large_exp_to_16 = cast<u16>(large_width);
 
            auto large_exp_to_32 = cast<u32>(large_width);
 
            auto large_exp_to_64 = cast<u64>(large_width);
 

	
 
            auto small_exp_to_08 = cast<u8> (small_width);
 
            auto small_exp_to_16 = cast<u16>(small_width);
 
            auto small_exp_to_32 = cast<u32>(small_width);
 
            auto small_exp_to_64 = cast<u64>(small_width);
 

	
 
            // Implicit casting
 
            u8  large_imp_to_08 = cast(large_width);
 
            u16 large_imp_to_16 = cast(large_width);
 
            u32 large_imp_to_32 = cast(large_width);
 
            u64 large_imp_to_64 = cast(large_width);
 

	
 
            u8  small_imp_to_08 = cast(small_width);
 
            u16 small_imp_to_16 = cast(small_width);
 
            u32 small_imp_to_32 = cast(small_width);
 
            u64 small_imp_to_64 = cast(small_width);
 

	
 
            return
 
                large_exp_to_08 == 255 && large_exp_to_16 == 255 && large_exp_to_32 == 255 && large_exp_to_64 == 255 &&
 
                small_exp_to_08 == 255 && small_exp_to_16 == 255 && small_exp_to_32 == 255 && small_exp_to_64 == 255 &&
 
                large_imp_to_08 == 255 && large_imp_to_16 == 255 && large_imp_to_32 == 255 && large_imp_to_64 == 255 &&
 
                small_imp_to_08 == 255 && small_imp_to_16 == 255 && small_imp_to_32 == 255 && small_imp_to_64 == 255;
 
        }
 
    ").for_function("foo", |f| { f
 
        .call_ok(Some(Value::Bool(true)));
 
    });
 
}
 

	
 
#[test]
 
fn test_invalid_casting() {
 
    fn generate_source(input_type: &str, input_value: &str, output_type: &str) -> String {
 
        return format!("
 
        func foo() -> u32 {{
 
            {} value = {};
 
            {} result = cast(value);
 
            return 0;
 
        }}
 
        ", input_type, input_value, output_type);
 
    }
 

	
 
    fn perform_test(input_type: &str, input_value: &str, output_type: &str) {
 
        Tester::new_single_source_expect_ok(
 
            format!("invalid cast {} to {}", input_type, output_type),
 
            generate_source(input_type, input_value, output_type)
 
        ).for_function("foo", |f| {
 
            f.call_err(&format!("'{}' which doesn't fit in a type '{}'", input_value, output_type));
 
        });
 
    }
 

	
 
    // Not exhaustive, good enough
 
    let tests = [
 
        ("u16", "256", "u8"),
 
        ("u32", "256", "u8"),
 
        ("u64", "256", "u8"),
 
        ("u32", "65536", "u16"),
 
        ("u64", "65536", "u16"),
 
        ("s8", "-1", "u8"),
 
        ("s32", "-1", "u16"),
 
        ("s32", "65536", "u16"),
 
        ("s16", "-129", "s8"),
 
        ("s16", "128", "s8")
 
    ];
 

	
 
    for (input_type, input_value, output_type) in &tests {
 
        perform_test(input_type, input_value, output_type);
 
    }
 
}
 
\ No newline at end of file
src/protocol/tests/mod.rs
Show inline comments
 
/**
 
 * protocol/tests.rs
 
 *
 
 * Contains tests for various parts of the lexer/parser and the evaluator of the
 
 * code. These are intended to be temporary tests such that we're sure that we
 
 * don't break existing functionality.
 
 *
 
 * In the future these should be replaced by proper testing protocols.
 
 */
 

	
 
mod utils;
 
mod lexer;
 
mod parser_validation;
 
mod parser_inference;
 
mod parser_monomorphs;
 
mod parser_imports;
 
mod eval_operators;
 
mod eval_calls;
 
mod eval_casting;
 
mod eval_silly;
 

	
 
pub(crate) use utils::{Tester}; // the testing harness
 
pub(crate) use crate::protocol::eval::value::*; // to test functions
 
\ No newline at end of file
src/protocol/tests/utils.rs
Show inline comments
 
use crate::collections::StringPool;
 
use crate::protocol::{
 
    Module,
 
    ast::*,
 
    input_source::*,
 
    parser::{
 
        Parser,
 
        type_table::{TypeTable, DefinedTypeVariant},
 
        symbol_table::SymbolTable,
 
        token_parsing::*,
 
    },
 
    eval::*,
 
};
 

	
 
// Carries information about the test into utility structures for builder-like
 
// assertions
 
#[derive(Clone, Copy)]
 
struct TestCtx<'a> {
 
    test_name: &'a str,
 
    heap: &'a Heap,
 
    modules: &'a Vec<Module>,
 
    types: &'a TypeTable,
 
    symbols: &'a SymbolTable,
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Interface for parsing and compiling
 
//------------------------------------------------------------------------------
 

	
 
pub(crate) struct Tester {
 
    test_name: String,
 
    sources: Vec<String>
 
}
 

	
 
impl Tester {
 
    /// Constructs a new tester, allows adding multiple sources before compiling
 
    pub(crate) fn new<S: ToString>(test_name: S) -> Self {
 
        Self{
 
            test_name: test_name.to_string(),
 
            sources: Vec::new()
 
        }
 
    }
 

	
 
    /// Utility for quick tests that use a single source file and expect the
 
    /// compilation to succeed.
 
    pub(crate) fn new_single_source_expect_ok<T: ToString, S: ToString>(test_name: T, source: S) -> AstOkTester {
 
        Self::new(test_name)
 
            .with_source(source)
 
            .compile()
 
            .expect_ok()
 
    }
 

	
 
    /// Utility for quick tests that use a single source file and expect the
 
    /// compilation to fail.
 
    pub(crate) fn new_single_source_expect_err<T: ToString, S: ToString>(test_name: T, source: S) -> AstErrTester {
 
        Self::new(test_name)
 
            .with_source(source)
 
            .compile()
 
            .expect_err()
 
    }
 

	
 
    pub(crate) fn with_source<S: ToString>(mut self, source: S) -> Self {
 
        self.sources.push(source.to_string());
 
        self
 
    }
 

	
 
    pub(crate) fn compile(self) -> AstTesterResult {
 
        let mut parser = Parser::new();
 
        for source in self.sources.into_iter() {
 
            let source = source.into_bytes();
 
            let input_source = InputSource::new(String::from(""), source);
 

	
 
            if let Err(err) = parser.feed(input_source) {
 
                return AstTesterResult::Err(AstErrTester::new(self.test_name, err))
 
            }
 
        }
 

	
 
        if let Err(err) = parser.parse() {
 
            return AstTesterResult::Err(AstErrTester::new(self.test_name, err))
 
        }
 

	
 
        AstTesterResult::Ok(AstOkTester::new(self.test_name, parser))
 
    }
 
}
 

	
 
pub(crate) enum AstTesterResult {
 
    Ok(AstOkTester),
 
    Err(AstErrTester)
 
}
 

	
 
impl AstTesterResult {
 
    pub(crate) fn expect_ok(self) -> AstOkTester {
 
        match self {
 
            AstTesterResult::Ok(v) => v,
 
            AstTesterResult::Err(err) => {
 
                let wrapped = ErrorTester{ test_name: &err.test_name, error: &err.error };
 
                println!("DEBUG: Full error:\n{}", &err.error);
 
                assert!(
 
                    false,
 
                    "[{}] Expected compilation to succeed, but it failed with {}",
 
                    err.test_name, wrapped.assert_postfix()
 
                );
 
                unreachable!();
 
            }
 
        }
 
    }
 

	
 
    pub(crate) fn expect_err(self) -> AstErrTester {
 
        match self {
 
            AstTesterResult::Ok(ok) => {
 
                assert!(false, "[{}] Expected compilation to fail, but it succeeded", ok.test_name);
 
                unreachable!();
 
            },
 
            AstTesterResult::Err(err) => err,
 
        }
 
    }
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Interface for successful compilation
 
//------------------------------------------------------------------------------
 

	
 
pub(crate) struct AstOkTester {
 
    test_name: String,
 
    modules: Vec<Module>,
 
    heap: Heap,
 
    symbols: SymbolTable,
 
    types: TypeTable,
 
    pool: StringPool, // This is stored because if we drop it on the floor, we lose all our `StringRef<'static>`s
 
}
 

	
 
impl AstOkTester {
 
    fn new(test_name: String, parser: Parser) -> Self {
 
        Self {
 
            test_name,
 
            modules: parser.modules.into_iter().map(|module| Module{
 
                source: module.source,
 
                root_id: module.root_id,
 
                name: module.name.map(|(_, name)| name)
 
            }).collect(),
 
            heap: parser.heap,
 
            symbols: parser.symbol_table,
 
            types: parser.type_table,
 
            pool: parser.string_pool,
 
        }
 
    }
 

	
 
    pub(crate) fn for_struct<F: Fn(StructTester)>(self, name: &str, f: F) -> Self {
 
        let mut found = false;
 
        for definition in self.heap.definitions.iter() {
 
            if let Definition::Struct(definition) = definition {
 
                if definition.identifier.value.as_str() != name {
 
                    continue;
 
                }
 

	
 
                // Found struct with the same name
 
                let tester = StructTester::new(self.ctx(), definition);
 
                f(tester);
 
                found = true;
 
                break
 
            }
 
        }
 

	
 
        assert!(
 
            found, "[{}] Failed to find definition for struct '{}'",
 
            self.test_name, name
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn for_enum<F: Fn(EnumTester)>(self, name: &str, f: F) -> Self {
 
        let mut found = false;
 
        for definition in self.heap.definitions.iter() {
 
            if let Definition::Enum(definition) = definition {
 
                if definition.identifier.value.as_str() != name {
 
                    continue;
 
                }
 

	
 
                // Found enum with the same name
 
                let tester = EnumTester::new(self.ctx(), definition);
 
                f(tester);
 
                found = true;
 
                break;
 
            }
 
        }
 

	
 
        assert!(
 
            found, "[{}] Failed to find definition for enum '{}'",
 
            self.test_name, name
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn for_union<F: Fn(UnionTester)>(self, name: &str, f: F) -> Self {
 
        let mut found = false;
 
        for definition in self.heap.definitions.iter() {
 
            if let Definition::Union(definition) = definition {
 
                if definition.identifier.value.as_str() != name {
 
                    continue;
 
                }
 

	
 
                // Found union with the same name
 
                let tester = UnionTester::new(self.ctx(), definition);
 
                f(tester);
 
                found = true;
 
                break;
 
            }
 
        }
 

	
 
        assert!(
 
            found, "[{}] Failed to find definition for union '{}'",
 
            self.test_name, name
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn for_function<F: FnOnce(FunctionTester)>(self, name: &str, f: F) -> Self {
 
        let mut found = false;
 
        for definition in self.heap.definitions.iter() {
 
            if let Definition::Function(definition) = definition {
 
                if definition.identifier.value.as_str() != name {
 
                    continue;
 
                }
 

	
 
                // Found function
 
                let tester = FunctionTester::new(self.ctx(), definition);
 
                f(tester);
 
                found = true;
 
                break;
 
            }
 
        }
 

	
 
        if found { return self }
 

	
 
        assert!(
 
            false, "[{}] failed to find definition for function '{}'",
 
            self.test_name, name
 
        );
 
        unreachable!();
 
    }
 

	
 
    fn ctx(&self) -> TestCtx {
 
        TestCtx{
 
            test_name: &self.test_name,
 
            modules: &self.modules,
 
            heap: &self.heap,
 
            types: &self.types,
 
            symbols: &self.symbols,
 
        }
 
    }
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Utilities for successful compilation
 
//------------------------------------------------------------------------------
 

	
 
pub(crate) struct StructTester<'a> {
 
    ctx: TestCtx<'a>,
 
    def: &'a StructDefinition,
 
}
 

	
 
impl<'a> StructTester<'a> {
 
    fn new(ctx: TestCtx<'a>, def: &'a StructDefinition) -> Self {
 
        Self{ ctx, def }
 
    }
 

	
 
    pub(crate) fn assert_num_fields(self, num: usize) -> Self {
 
        assert_eq!(
 
            num, self.def.fields.len(),
 
            "[{}] Expected {} struct fields, but found {} for {}",
 
            self.ctx.test_name, num, self.def.fields.len(), self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_num_monomorphs(self, num: usize) -> Self {
 
        let (is_equal, num_encountered) = has_equal_num_monomorphs(self.ctx, num, self.def.this.upcast());
 
        assert!(
 
            is_equal, "[{}] Expected {} monomorphs, but got {} for {}",
 
            self.ctx.test_name, num, num_encountered, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    /// Asserts that a monomorph exist, separate polymorphic variable types by
 
    /// a semicolon.
 
    pub(crate) fn assert_has_monomorph(self, serialized_monomorph: &str) -> Self {
 
        let (has_monomorph, serialized) = has_monomorph(self.ctx, self.def.this.upcast(), serialized_monomorph);
 
        assert!(
 
            has_monomorph, "[{}] Expected to find monomorph {}, but got {} for {}",
 
            self.ctx.test_name, serialized_monomorph, &serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn for_field<F: Fn(StructFieldTester)>(self, name: &str, f: F) -> Self {
 
        // Find field with specified name
 
        for field in &self.def.fields {
 
            if field.field.value.as_str() == name {
 
                let tester = StructFieldTester::new(self.ctx, field);
 
                f(tester);
 
                return self;
 
            }
 
        }
 

	
 
        assert!(
 
            false, "[{}] Could not find struct field '{}' for {}",
 
            self.ctx.test_name, name, self.assert_postfix()
 
        );
 
        unreachable!();
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        let mut v = String::new();
 
        v.push_str("Struct{ name: ");
 
        v.push_str(self.def.identifier.value.as_str());
 
        v.push_str(", fields: [");
 
        for (field_idx, field) in self.def.fields.iter().enumerate() {
 
            if field_idx != 0 { v.push_str(", "); }
 
            v.push_str(field.field.value.as_str());
 
        }
 
        v.push_str("] }");
 
        v
 
    }
 
}
 

	
 
pub(crate) struct StructFieldTester<'a> {
 
    ctx: TestCtx<'a>,
 
    def: &'a StructFieldDefinition,
 
}
 

	
 
impl<'a> StructFieldTester<'a> {
 
    fn new(ctx: TestCtx<'a>, def: &'a StructFieldDefinition) -> Self {
 
        Self{ ctx, def }
 
    }
 

	
 
    pub(crate) fn assert_parser_type(self, expected: &str) -> Self {
 
        let mut serialized_type = String::new();
 
        serialize_parser_type(&mut serialized_type, &self.ctx.heap, &self.def.parser_type);
 
        assert_eq!(
 
            expected, &serialized_type,
 
            "[{}] Expected type '{}', but got '{}' for {}",
 
            self.ctx.test_name, expected, &serialized_type, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        let mut serialized_type = String::new();
 
        serialize_parser_type(&mut serialized_type, &self.ctx.heap, &self.def.parser_type);
 
        format!("StructField{{ name: {}, parser_type: {} }}", self.def.field.value.as_str(), serialized_type)
 
    }
 
}
 

	
 
pub(crate) struct EnumTester<'a> {
 
    ctx: TestCtx<'a>,
 
    def: &'a EnumDefinition,
 
}
 

	
 
impl<'a> EnumTester<'a> {
 
    fn new(ctx: TestCtx<'a>, def: &'a EnumDefinition) -> Self {
 
        Self{ ctx, def }
 
    }
 

	
 
    pub(crate) fn assert_num_variants(self, num: usize) -> Self {
 
        assert_eq!(
 
            num, self.def.variants.len(),
 
            "[{}] Expected {} enum variants, but found {} for {}",
 
            self.ctx.test_name, num, self.def.variants.len(), self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_num_monomorphs(self, num: usize) -> Self {
 
        let (is_equal, num_encountered) = has_equal_num_monomorphs(self.ctx, num, self.def.this.upcast());
 
        assert!(
 
            is_equal, "[{}] Expected {} monomorphs, but got {} for {}",
 
            self.ctx.test_name, num, num_encountered, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_has_monomorph(self, serialized_monomorph: &str) -> Self {
 
        let (has_monomorph, serialized) = has_monomorph(self.ctx, self.def.this.upcast(), serialized_monomorph);
 
        assert!(
 
            has_monomorph, "[{}] Expected to find monomorph {}, but got {} for {}",
 
            self.ctx.test_name, serialized_monomorph, serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_postfix(&self) -> String {
 
        let mut v = String::new();
 
        v.push_str("Enum{ name: ");
 
        v.push_str(self.def.identifier.value.as_str());
 
        v.push_str(", variants: [");
 
        for (variant_idx, variant) in self.def.variants.iter().enumerate() {
 
            if variant_idx != 0 { v.push_str(", "); }
 
            v.push_str(variant.identifier.value.as_str());
 
        }
 
        v.push_str("] }");
 
        v
 
    }
 
}
 

	
 
pub(crate) struct UnionTester<'a> {
 
    ctx: TestCtx<'a>,
 
    def: &'a UnionDefinition,
 
}
 

	
 
impl<'a> UnionTester<'a> {
 
    fn new(ctx: TestCtx<'a>, def: &'a UnionDefinition) -> Self {
 
        Self{ ctx, def }
 
    }
 

	
 
    pub(crate) fn assert_num_variants(self, num: usize) -> Self {
 
        assert_eq!(
 
            num, self.def.variants.len(),
 
            "[{}] Expected {} union variants, but found {} for {}",
 
            self.ctx.test_name, num, self.def.variants.len(), self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_num_monomorphs(self, num: usize) -> Self {
 
        let (is_equal, num_encountered) = has_equal_num_monomorphs(self.ctx, num, self.def.this.upcast());
 
        assert!(
 
            is_equal, "[{}] Expected {} monomorphs, but got {} for {}",
 
            self.ctx.test_name, num, num_encountered, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_has_monomorph(self, serialized_monomorph: &str) -> Self {
 
        let (has_monomorph, serialized) = has_monomorph(self.ctx, self.def.this.upcast(), serialized_monomorph);
 
        assert!(
 
            has_monomorph, "[{}] Expected to find monomorph {}, but got {} for {}",
 
            self.ctx.test_name, serialized_monomorph, serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        let mut v = String::new();
 
        v.push_str("Union{ name: ");
 
        v.push_str(self.def.identifier.value.as_str());
 
        v.push_str(", variants: [");
 
        for (variant_idx, variant) in self.def.variants.iter().enumerate() {
 
            if variant_idx != 0 { v.push_str(", "); }
 
            v.push_str(variant.identifier.value.as_str());
 
        }
 
        v.push_str("] }");
 
        v
 
    }
 
}
 

	
 
pub(crate) struct FunctionTester<'a> {
 
    ctx: TestCtx<'a>,
 
    def: &'a FunctionDefinition,
 
}
 

	
 
impl<'a> FunctionTester<'a> {
 
    fn new(ctx: TestCtx<'a>, def: &'a FunctionDefinition) -> Self {
 
        Self{ ctx, def }
 
    }
 

	
 
    pub(crate) fn for_variable<F: Fn(VariableTester)>(self, name: &str, f: F) -> Self {
 
        // Find the memory statement in order to find the local
 
        let mem_stmt_id = seek_stmt(
 
            self.ctx.heap, self.def.body.upcast(),
 
            &|stmt| {
 
                if let Statement::Local(local) = stmt {
 
                    if let LocalStatement::Memory(memory) = local {
 
                        let local = &self.ctx.heap[memory.variable];
 
                        if local.identifier.value.as_str() == name {
 
                            return true;
 
                        }
 
                    }
 
                }
 

	
 
                false
 
            }
 
        );
 

	
 
        assert!(
 
            mem_stmt_id.is_some(), "[{}] Failed to find variable '{}' in {}",
 
            self.ctx.test_name, name, self.assert_postfix()
 
        );
 

	
 
        let mem_stmt_id = mem_stmt_id.unwrap();
 
        let local_id = self.ctx.heap[mem_stmt_id].as_memory().variable;
 
        let local = &self.ctx.heap[local_id];
 

	
 
        // Find the assignment expression that follows it
 
        let assignment_id = seek_expr_in_stmt(
 
            self.ctx.heap, self.def.body.upcast(),
 
            &|expr| {
 
                if let Expression::Assignment(assign_expr) = expr {
 
                    if let Expression::Variable(variable_expr) = &self.ctx.heap[assign_expr.left] {
 
                        if variable_expr.identifier.span.begin.offset == local.identifier.span.begin.offset {
 
                            return true;
 
                        }
 
                    }
 
                }
 

	
 
                false
 
            }
 
        );
 

	
 
        assert!(
 
            assignment_id.is_some(), "[{}] Failed to find assignment to variable '{}' in {}",
 
            self.ctx.test_name, name, self.assert_postfix()
 
        );
 

	
 
        let assignment = &self.ctx.heap[assignment_id.unwrap()];
 

	
 
        // Construct tester and pass to tester function
 
        let tester = VariableTester::new(
 
            self.ctx, self.def.this.upcast(), local, 
 
            assignment.as_assignment()
 
        );
 
        f(tester);
 

	
 
        self
 
    }
 

	
 
    /// Finds a specific expression within a function. There are two matchers:
 
    /// one outer matcher (to find a rough indication of the expression) and an
 
    /// inner matcher to find the exact expression. 
 
    ///
 
    /// The reason being that, for example, a function's body might be littered
 
    /// with addition symbols, so we first match on "some_var + some_other_var",
 
    /// and then match exactly on "+".
 
    pub(crate) fn for_expression_by_source<F: Fn(ExpressionTester)>(self, outer_match: &str, inner_match: &str, f: F) -> Self {
 
        // Seek the expression in the source code
 
        assert!(outer_match.contains(inner_match), "improper testing code");
 

	
 
        let module = seek_def_in_modules(
 
            &self.ctx.heap, &self.ctx.modules, self.def.this.upcast()
 
        ).unwrap();
 

	
 
        // Find the first occurrence of the expression after the definition of
 
        // the function, we'll check that it is included in the body later.
 
        let mut outer_match_idx = self.def.span.begin.offset as usize;
 
        while outer_match_idx < module.source.input.len() {
 
            if module.source.input[outer_match_idx..].starts_with(outer_match.as_bytes()) {
 
                break;
 
            }
 
            outer_match_idx += 1
 
        }
 

	
 
        assert!(
 
            outer_match_idx < module.source.input.len(),
 
            "[{}] Failed to find '{}' within the source that contains {}",
 
            self.ctx.test_name, outer_match, self.assert_postfix()
 
        );
 
        let inner_match_idx = outer_match_idx + outer_match.find(inner_match).unwrap();
 

	
 
        // Use the inner match index to find the expression
 
        let expr_id = seek_expr_in_stmt(
 
            &self.ctx.heap, self.def.body.upcast(),
 
            &|expr| expr.span().begin.offset as usize == inner_match_idx
 
        );
 
        assert!(
 
            expr_id.is_some(),
 
            "[{}] Failed to find '{}' within the source that contains {} \
 
            (note: expression was found, but not within the specified function",
 
            self.ctx.test_name, outer_match, self.assert_postfix()
 
        );
 
        let expr_id = expr_id.unwrap();
 

	
 
        // We have the expression, call the testing function
 
        let tester = ExpressionTester::new(
 
            self.ctx, self.def.this.upcast(), &self.ctx.heap[expr_id]
 
        );
 
        f(tester);
 

	
 
        self
 
    }
 

	
 
    pub(crate) fn call_ok(self, expected_result: Option<Value>) -> Self {
 
        use crate::protocol::*;
 
        use crate::runtime::*;
 

	
 
        let (prompt, result) = self.eval_until_end();
 
        match result {
 
            Ok(_) => {
 
                assert!(
 
                    prompt.store.stack.len() > 0, // note: stack never shrinks
 
                    "[{}] No value on stack after calling function for {}",
 
                    self.ctx.test_name, self.assert_postfix()
 
                );
 
            },
 
            Err(err) => {
 
                println!("DEBUG: Formatted error:\n{}", err);
 
                assert!(
 
                    false,
 
                    "[{}] Expected call to succeed, but got {:?} for {}",
 
                    self.ctx.test_name, err, self.assert_postfix()
 
                )
 
            }
 
        }
 

	
 
        if let Some(expected_result) = expected_result {
 
            debug_assert!(expected_result.get_heap_pos().is_none(), "comparing against heap thingamajigs is not yet implemented");
 
            assert!(
 
                value::apply_equality_operator(&prompt.store, &prompt.store.stack[0], &expected_result),
 
                "[{}] Result from call was {:?}, but expected {:?} for {}",
 
                self.ctx.test_name, &prompt.store.stack[0], &expected_result, self.assert_postfix()
 
            )
 
        }
 

	
 
        self
 
    }
 

	
 
    // Keeping this simple for now, will likely change
 
    pub(crate) fn call_err(self, expected_result: &str) -> Self {
 
        use crate::protocol::*;
 
        use crate::runtime::*;
 

	
 
        let (_, result) = self.eval_until_end();
 
        match result {
 
            Ok(_) => {
 
                assert!(
 
                    false,
 
                    "[{}] Expected an error, but evaluation finished successfully for {}",
 
                    self.ctx.test_name, self.assert_postfix()
 
                );
 
            },
 
            Err(err) => {
 
                println!("DEBUG: Got evaluation error:\n{}", err);
 
                debug_assert_eq!(err.statements.len(), 1);
 
                assert!(
 
                    err.statements[0].message.contains(&expected_result),
 
                    "[{}] Expected error message to contain '{}', but it was '{}' for {}",
 
                    self.ctx.test_name, expected_result, err.statements[0].message, self.assert_postfix()
 
                );
 
            }
 
        }
 

	
 
        self
 
    }
 

	
 
    fn eval_until_end(&self) -> (Prompt, Result<EvalContinuation, EvalError>) {
 
        use crate::protocol::*;
 
        use crate::runtime::*;
 

	
 
        let mut prompt = Prompt::new(&self.ctx.types, &self.ctx.heap, self.def.this.upcast(), 0, ValueGroup::new_stack(Vec::new()));
 
        let mut call_context = EvalContext::None;
 
        loop {
 
            let result = prompt.step(&self.ctx.types, &self.ctx.heap, &self.ctx.modules, &mut call_context);
 
            match result {
 
                Ok(EvalContinuation::Stepping) => {},
 
                _ => return (prompt, result),
 
            }
 
        }
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        format!("Function{{ name: {} }}", self.def.identifier.value.as_str())
 
    }
 
}
 

	
 
pub(crate) struct VariableTester<'a> {
 
    ctx: TestCtx<'a>,
 
    definition_id: DefinitionId,
 
    variable: &'a Variable,
 
    assignment: &'a AssignmentExpression,
 
}
 

	
 
impl<'a> VariableTester<'a> {
 
    fn new(
 
        ctx: TestCtx<'a>, definition_id: DefinitionId, variable: &'a Variable, assignment: &'a AssignmentExpression
 
    ) -> Self {
 
        Self{ ctx, definition_id, variable, assignment }
 
    }
 

	
 
    pub(crate) fn assert_parser_type(self, expected: &str) -> Self {
 
        let mut serialized = String::new();
 
        serialize_parser_type(&mut serialized, self.ctx.heap, &self.variable.parser_type);
 

	
 
        assert_eq!(
 
            expected, &serialized,
 
            "[{}] Expected parser type '{}', but got '{}' for {}",
 
            self.ctx.test_name, expected, &serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    pub(crate) fn assert_concrete_type(self, expected: &str) -> Self {
 
        // Lookup concrete type in type table
 
        let mono_data = self.ctx.types.get_procedure_expression_data(&self.definition_id, 0);
 
        let lhs = self.ctx.heap[self.assignment.left].as_variable();
 
        let concrete_type = &mono_data.expr_data[lhs.unique_id_in_definition as usize].expr_type;
 

	
 
        // Serialize and check
 
        let mut serialized = String::new();
 
        serialize_concrete_type(&mut serialized, self.ctx.heap, self.definition_id, concrete_type);
 

	
 
        assert_eq!(
 
            expected, &serialized,
 
            "[{}] Expected concrete type '{}', but got '{}' for {}",
 
            self.ctx.test_name, expected, &serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        format!("Variable{{ name: {} }}", self.variable.identifier.value.as_str())
 
    }
 
}
 

	
 
pub(crate) struct ExpressionTester<'a> {
 
    ctx: TestCtx<'a>,
 
    definition_id: DefinitionId, // of the enclosing function/component
 
    expr: &'a Expression
 
}
 

	
 
impl<'a> ExpressionTester<'a> {
 
    fn new(
 
        ctx: TestCtx<'a>, definition_id: DefinitionId, expr: &'a Expression
 
    ) -> Self {
 
        Self{ ctx, definition_id, expr }
 
    }
 

	
 
    pub(crate) fn assert_concrete_type(self, expected: &str) -> Self {
 
        // Lookup concrete type
 
        let mono_data = self.ctx.types.get_procedure_expression_data(&self.definition_id, 0);
 
        let expr_index = self.expr.get_unique_id_in_definition();
 
        let concrete_type = &mono_data.expr_data[expr_index as usize].expr_type;
 

	
 
        // Serialize and check type
 
        let mut serialized = String::new();
 
        serialize_concrete_type(&mut serialized, self.ctx.heap, self.definition_id, concrete_type);
 

	
 
        assert_eq!(
 
            expected, &serialized,
 
            "[{}] Expected concrete type '{}', but got '{}' for {}",
 
            self.ctx.test_name, expected, &serialized, self.assert_postfix()
 
        );
 
        self
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        format!(
 
            "Expression{{ debug: {:?} }}",
 
            self.expr
 
        )
 
    }
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Interface for failed compilation
 
//------------------------------------------------------------------------------
 

	
 
pub(crate) struct AstErrTester {
 
    test_name: String,
 
    error: ParseError,
 
}
 

	
 
impl AstErrTester {
 
    fn new(test_name: String, error: ParseError) -> Self {
 
        Self{ test_name, error }
 
    }
 

	
 
    pub(crate) fn error<F: Fn(ErrorTester)>(&self, f: F) {
 
        // Maybe multiple errors will be supported in the future
 
        let tester = ErrorTester{ test_name: &self.test_name, error: &self.error };
 
        f(tester)
 
    }
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Utilities for failed compilation
 
//------------------------------------------------------------------------------
 

	
 
pub(crate) struct ErrorTester<'a> {
 
    test_name: &'a str,
 
    error: &'a ParseError,
 
}
 

	
 
impl<'a> ErrorTester<'a> {
 
    pub(crate) fn assert_num(self, num: usize) -> Self {
 
        assert_eq!(
 
            num, self.error.statements.len(),
 
            "[{}] expected error to consist of '{}' parts, but encountered '{}' for {}",
 
            self.test_name, num, self.error.statements.len(), self.assert_postfix()
 
        );
 

	
 
        self
 
    }
 

	
 
    pub(crate) fn assert_ctx_has(self, idx: usize, msg: &str) -> Self {
 
        assert!(
 
            self.error.statements[idx].context.contains(msg),
 
            "[{}] expected error statement {}'s context to contain '{}' for {}",
 
            self.test_name, idx, msg, self.assert_postfix()
 
        );
 

	
 
        self
 
    }
 

	
 
    pub(crate) fn assert_msg_has(self, idx: usize, msg: &str) -> Self {
 
        assert!(
 
            self.error.statements[idx].message.contains(msg),
 
            "[{}] expected error statement {}'s message to contain '{}' for {}",
 
            self.test_name, idx, msg, self.assert_postfix()
 
        );
 

	
 
        self
 
    }
 

	
 
    // TODO: @tokenizer This should really be removed, as compilation should be
 
    //  deterministic, but we're currently using rather inefficient hashsets for
 
    //  the type inference, so remove once compiler architecture has changed.
 
    pub(crate) fn assert_any_msg_has(self, msg: &str) -> Self {
 
        let mut is_present = false;
 
        for statement in &self.error.statements {
 
            if statement.message.contains(msg) {
 
                is_present = true;
 
                break;
 
            }
 
        }
 

	
 
        assert!(
 
            is_present, "[{}] Expected an error statement to contain '{}' for {}",
 
            self.test_name, msg, self.assert_postfix()
 
        );
 
        
 
        self
 
    }
 

	
 
    /// Seeks the index of the pattern in the context message, then checks if
 
    /// the input position corresponds to that index.
 
    pub (crate) fn assert_occurs_at(self, idx: usize, pattern: &str) -> Self {
 
        let pos = self.error.statements[idx].context.find(pattern);
 
        assert!(
 
            pos.is_some(),
 
            "[{}] incorrect occurs_at: '{}' could not be found in the context for {}",
 
            self.test_name, pattern, self.assert_postfix()
 
        );
 
        let pos = pos.unwrap();
 
        let col = self.error.statements[idx].start_column as usize;
 
        assert_eq!(
 
            pos + 1, col,
 
            "[{}] Expected error to occur at column {}, but found it at {} for {}",
 
            self.test_name, pos + 1, col, self.assert_postfix()
 
        );
 

	
 
        self
 
    }
 

	
 
    fn assert_postfix(&self) -> String {
 
        let mut v = String::new();
 
        v.push_str("error: [");
 
        for (idx, stmt) in self.error.statements.iter().enumerate() {
 
            if idx != 0 {
 
                v.push_str(", ");
 
            }
 

	
 
            v.push_str(&format!("{{ context: {}, message: {} }}", &stmt.context, stmt.message));
 
        }
 
        v.push(']');
 
        v
 
    }
 
}
 

	
 
//------------------------------------------------------------------------------
 
// Generic utilities
 
//------------------------------------------------------------------------------
 

	
 
fn has_equal_num_monomorphs(ctx: TestCtx, num: usize, definition_id: DefinitionId) -> (bool, usize) {
 
    use DefinedTypeVariant::*;
 

	
 
    let type_def = ctx.types.get_base_definition(&definition_id).unwrap();
 
    let num_on_type = match &type_def.definition {
 
        Struct(v) => v.monomorphs.len(),
 
        Enum(v) => v.monomorphs.len(),
 
        Union(v) => v.monomorphs.len(),
 
        Function(v) => v.monomorphs.len(),
 
        Component(v) => v.monomorphs.len(),
 
    };
 

	
 
    (num_on_type == num, num_on_type)
 
}
 

	
 
fn has_monomorph(ctx: TestCtx, definition_id: DefinitionId, serialized_monomorph: &str) -> (bool, String) {
 
    use DefinedTypeVariant::*;
 

	
 
    let type_def = ctx.types.get_base_definition(&definition_id).unwrap();
 

	
 
    // Note: full_buffer is just for error reporting
 
    let mut full_buffer = String::new();
 
    let mut has_match = false;
 

	
 
    let serialize_monomorph = |monomorph: &Vec<ConcreteType>| -> String {
 
        let mut buffer = String::new();
 
        for (element_idx, element) in monomorph.iter().enumerate() {
 
            if element_idx != 0 {
 
                buffer.push(';');
 
            }
 
            serialize_concrete_type(&mut buffer, ctx.heap, definition_id, element);
 
        }
 

	
 
        buffer
 
    };
 

	
 
    full_buffer.push('[');
 
    let mut append_to_full_buffer = |buffer: String| {
 
        if full_buffer.len() != 1 {
 
            full_buffer.push_str(", ");
 
        }
 
        full_buffer.push('"');
 
        full_buffer.push_str(&buffer);
 
        full_buffer.push('"');
 
    };
 

	
 
    match &type_def.definition {
 
        Enum(_) | Union(_) | Struct(_) => {
 
            let monomorphs = type_def.definition.data_monomorphs();
 
            for monomorph in monomorphs.iter() {
 
                let buffer = serialize_monomorph(&monomorph.poly_args);
 
                if buffer == serialized_monomorph {
 
                    has_match = true;
 
                }
 
                append_to_full_buffer(buffer);
 
            }
 
        },
 
        Function(_) | Component(_) => {
 
            let monomorphs = type_def.definition.procedure_monomorphs();
 
            for monomorph in monomorphs.iter() {
 
                let buffer = serialize_monomorph(&monomorph.poly_args);
 
                if buffer == serialized_monomorph {
 
                    has_match = true;
 
                }
 
                append_to_full_buffer(buffer);
 
            }
 
        }
 
    }
 

	
 
    full_buffer.push(']');
 

	
 
    (has_match, full_buffer)
 
}
 

	
 
fn serialize_parser_type(buffer: &mut String, heap: &Heap, parser_type: &ParserType) {
 
    use ParserTypeVariant as PTV;
 

	
 
    fn write_bytes(buffer: &mut String, bytes: &[u8]) {
 
        let utf8 = String::from_utf8_lossy(bytes);
 
        buffer.push_str(&utf8);
 
    }
 

	
 
    fn serialize_variant(buffer: &mut String, heap: &Heap, parser_type: &ParserType, mut idx: usize) -> usize {
 
        match &parser_type.elements[idx].variant {
 
            PTV::Void => buffer.push_str("void"),
 
            PTV::InputOrOutput => {
 
                buffer.push_str("portlike<");
 
                idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                buffer.push('>');
 
            },
 
            PTV::ArrayLike => {
 
                idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                buffer.push_str("[???]");
 
            },
 
            PTV::IntegerLike => buffer.push_str("integerlike"),
 
            PTV::Message => buffer.push_str(KW_TYPE_MESSAGE_STR),
 
            PTV::Bool => buffer.push_str(KW_TYPE_BOOL_STR),
 
            PTV::UInt8 => buffer.push_str(KW_TYPE_UINT8_STR),
 
            PTV::UInt16 => buffer.push_str(KW_TYPE_UINT16_STR),
 
            PTV::UInt32 => buffer.push_str(KW_TYPE_UINT32_STR),
 
            PTV::UInt64 => buffer.push_str(KW_TYPE_UINT64_STR),
 
            PTV::SInt8 => buffer.push_str(KW_TYPE_SINT8_STR),
 
            PTV::SInt16 => buffer.push_str(KW_TYPE_SINT16_STR),
 
            PTV::SInt32 => buffer.push_str(KW_TYPE_SINT32_STR),
 
            PTV::SInt64 => buffer.push_str(KW_TYPE_SINT64_STR),
 
            PTV::Character => buffer.push_str(KW_TYPE_CHAR_STR),
 
            PTV::String => buffer.push_str(KW_TYPE_STRING_STR),
 
            PTV::IntegerLiteral => buffer.push_str("int_literal"),
 
            PTV::Inferred => buffer.push_str(KW_TYPE_INFERRED_STR),
 
            PTV::Array => {
 
                idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                buffer.push_str("[]");
 
            },
 
            PTV::Input => {
 
                buffer.push_str(KW_TYPE_IN_PORT_STR);
 
                buffer.push('<');
 
                idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                buffer.push('>');
 
            },
 
            PTV::Output => {
 
                buffer.push_str(KW_TYPE_OUT_PORT_STR);
 
                buffer.push('<');
 
                idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                buffer.push('>');
 
            },
 
            PTV::PolymorphicArgument(definition_id, poly_idx) => {
 
                let definition = &heap[*definition_id];
 
                let poly_arg = &definition.poly_vars()[*poly_idx as usize];
 
                buffer.push_str(poly_arg.value.as_str());
 
            },
 
            PTV::Definition(definition_id, num_embedded) => {
 
                let definition = &heap[*definition_id];
 
                buffer.push_str(definition.identifier().value.as_str());
 

	
 
                let num_embedded = *num_embedded;
 
                if num_embedded != 0 {
 
                    buffer.push('<');
 
                    for embedded_idx in 0..num_embedded {
 
                        if embedded_idx != 0 {
 
                            buffer.push(',');
 
                        }
 
                        idx = serialize_variant(buffer, heap, parser_type, idx + 1);
 
                    }
 
                    buffer.push('>');
 
                }
 
            }
 
        }
 

	
 
        idx
 
    }
 

	
 
    serialize_variant(buffer, heap, parser_type, 0);
 
}
 

	
 
fn serialize_concrete_type(buffer: &mut String, heap: &Heap, def: DefinitionId, concrete: &ConcreteType) {
 
    // Retrieve polymorphic variables
 
    let poly_vars = heap[def].poly_vars();
 

	
 
    fn write_bytes(buffer: &mut String, bytes: &[u8]) {
 
        let utf8 = String::from_utf8_lossy(bytes);
 
        buffer.push_str(&utf8);
 
    }
 

	
 
    fn serialize_recursive(
 
        buffer: &mut String, heap: &Heap, poly_vars: &Vec<Identifier>, concrete: &ConcreteType, mut idx: usize
 
    ) -> usize {
 
        use ConcreteTypePart as CTP;
 

	
 
        let part = &concrete.parts[idx];
 
        match part {
 
            CTP::Void => buffer.push_str("void"),
 
            CTP::Message => write_bytes(buffer, KW_TYPE_MESSAGE),
 
            CTP::Bool => write_bytes(buffer, KW_TYPE_BOOL),
 
            CTP::UInt8 => write_bytes(buffer, KW_TYPE_UINT8),
 
            CTP::UInt16 => write_bytes(buffer, KW_TYPE_UINT16),
 
            CTP::UInt32 => write_bytes(buffer, KW_TYPE_UINT32),
 
            CTP::UInt64 => write_bytes(buffer, KW_TYPE_UINT64),
 
            CTP::SInt8 => write_bytes(buffer, KW_TYPE_SINT8),
 
            CTP::SInt16 => write_bytes(buffer, KW_TYPE_SINT16),
 
            CTP::SInt32 => write_bytes(buffer, KW_TYPE_SINT32),
 
            CTP::SInt64 => write_bytes(buffer, KW_TYPE_SINT64),
 
            CTP::Character => write_bytes(buffer, KW_TYPE_CHAR),
 
            CTP::String => write_bytes(buffer, KW_TYPE_STRING),
 
            CTP::Array => {
 
                idx = serialize_recursive(buffer, heap, poly_vars, concrete, idx + 1);
 
                buffer.push_str("[]");
 
            },
 
            CTP::Slice => {
 
                idx = serialize_recursive(buffer, heap, poly_vars, concrete, idx + 1);
 
                buffer.push_str("[..]");
 
            },
 
            CTP::Input => {
 
                write_bytes(buffer, KW_TYPE_IN_PORT);
 
                buffer.push('<');
 
                idx = serialize_recursive(buffer, heap, poly_vars, concrete, idx + 1);
 
                buffer.push('>');
 
            },
 
            CTP::Output => {
 
                write_bytes(buffer, KW_TYPE_OUT_PORT);
 
                buffer.push('<');
 
                idx = serialize_recursive(buffer, heap, poly_vars, concrete, idx + 1);
 
                buffer.push('>');
 
            },
 
            CTP::Instance(definition_id, num_sub) => {
 
                let definition_name = heap[*definition_id].identifier();
 
                buffer.push_str(definition_name.value.as_str());
 
                if *num_sub != 0 {
 
                    buffer.push('<');
 
                    for sub_idx in 0..*num_sub {
 
                        if sub_idx != 0 { buffer.push(','); }
 
                        idx = serialize_recursive(buffer, heap, poly_vars, concrete, idx + 1);
 
                    }
 
                    buffer.push('>');
 
                }
 
            }
 
        }
 

	
 
        idx
 
    }
 

	
 
    serialize_recursive(buffer, heap, poly_vars, concrete, 0);
 
}
 

	
 
fn seek_def_in_modules<'a>(heap: &Heap, modules: &'a [Module], def_id: DefinitionId) -> Option<&'a Module> {
 
    for module in modules {
 
        let root = &heap.protocol_descriptions[module.root_id];
 
        for definition in &root.definitions {
 
            if *definition == def_id {
 
                return Some(module)
 
            }
 
        }
 
    }
 

	
 
    None
 
}
 

	
 
fn seek_stmt<F: Fn(&Statement) -> bool>(heap: &Heap, start: StatementId, f: &F) -> Option<StatementId> {
 
    let stmt = &heap[start];
 
    if f(stmt) { return Some(start); }
 

	
 
    // This statement wasn't it, try to recurse
 
    let matched = match stmt {
 
        Statement::Block(block) => {
 
            for sub_id in &block.statements {
 
                if let Some(id) = seek_stmt(heap, *sub_id, f) {
 
                    return Some(id);
 
                }
 
            }
 

	
 
            None
 
        },
 
        Statement::Labeled(stmt) => seek_stmt(heap, stmt.body, f),
 
        Statement::If(stmt) => {
 
            if let Some(id) = seek_stmt(heap, stmt.true_body.upcast(), f) {
 
                return Some(id);
 
            } else if let Some(false_body) = stmt.false_body {
 
                if let Some(id) = seek_stmt(heap, false_body.upcast(), f) {
 
                    return Some(id);
 
                }
 
            }
 
            None
 
        },
 
        Statement::While(stmt) => seek_stmt(heap, stmt.body.upcast(), f),
 
        Statement::Synchronous(stmt) => seek_stmt(heap, stmt.body.upcast(), f),
 
        _ => None
 
    };
 

	
 
    matched
 
}
 

	
 
fn seek_expr_in_expr<F: Fn(&Expression) -> bool>(heap: &Heap, start: ExpressionId, f: &F) -> Option<ExpressionId> {
 
    let expr = &heap[start];
 
    if f(expr) { return Some(start); }
 

	
 
    match expr {
 
        Expression::Assignment(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.left, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.right, f))
 
        },
 
        Expression::Binding(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.left.upcast(), f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.right, f))
 
        }
 
        Expression::Conditional(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.test, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.true_expression, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.false_expression, f))
 
        },
 
        Expression::Binary(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.left, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.right, f))
 
        },
 
        Expression::Unary(expr) => {
 
            seek_expr_in_expr(heap, expr.expression, f)
 
        },
 
        Expression::Indexing(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.subject, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.index, f))
 
        },
 
        Expression::Slicing(expr) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, expr.subject, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.from_index, f))
 
            .or_else(|| seek_expr_in_expr(heap, expr.to_index, f))
 
        },
 
        Expression::Select(expr) => {
 
            seek_expr_in_expr(heap, expr.subject, f)
 
        },
 
        Expression::Literal(expr) => {
 
            if let Literal::Struct(lit) = &expr.value {
 
                for field in &lit.fields {
 
                    if let Some(id) = seek_expr_in_expr(heap, field.value, f) {
 
                        return Some(id)
 
                    }
 
                }
 
            } else if let Literal::Array(elements) = &expr.value {
 
                for element in elements {
 
                    if let Some(id) = seek_expr_in_expr(heap, *element, f) {
 
                        return Some(id)
 
                    }
 
                }
 
            }
 
            None
 
        },
 
        Expression::Cast(expr) => {
 
            seek_expr_in_expr(heap, expr.subject, f)
 
        }
 
        Expression::Call(expr) => {
 
            for arg in &expr.arguments {
 
                if let Some(id) = seek_expr_in_expr(heap, *arg, f) {
 
                    return Some(id)
 
                }
 
            }
 
            None
 
        },
 
        Expression::Variable(_expr) => {
 
            None
 
        }
 
    }
 
}
 

	
 
fn seek_expr_in_stmt<F: Fn(&Expression) -> bool>(heap: &Heap, start: StatementId, f: &F) -> Option<ExpressionId> {
 
    let stmt = &heap[start];
 

	
 
    match stmt {
 
        Statement::Block(stmt) => {
 
            for stmt_id in &stmt.statements {
 
                if let Some(id) = seek_expr_in_stmt(heap, *stmt_id, f) {
 
                    return Some(id)
 
                }
 
            }
 
            None
 
        },
 
        Statement::Labeled(stmt) => {
 
            seek_expr_in_stmt(heap, stmt.body, f)
 
        },
 
        Statement::If(stmt) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, stmt.test, f))
 
            .or_else(|| seek_expr_in_stmt(heap, stmt.true_body.upcast(), f))
 
            .or_else(|| if let Some(false_body) = stmt.false_body {
 
                seek_expr_in_stmt(heap, false_body.upcast(), f)
 
            } else {
 
                None
 
            })
 
        },
 
        Statement::While(stmt) => {
 
            None
 
            .or_else(|| seek_expr_in_expr(heap, stmt.test, f))
 
            .or_else(|| seek_expr_in_stmt(heap, stmt.body.upcast(), f))
 
        },
 
        Statement::Synchronous(stmt) => {
 
            seek_expr_in_stmt(heap, stmt.body.upcast(), f)
 
        },
 
        Statement::Return(stmt) => {
 
            for expr_id in &stmt.expressions {
 
                if let Some(id) = seek_expr_in_expr(heap, *expr_id, f) {
 
                    return Some(id);
 
                }
 
            }
 
            None
 
        },
 
        Statement::New(stmt) => {
 
            seek_expr_in_expr(heap, stmt.expression.upcast(), f)
 
        },
 
        Statement::Expression(stmt) => {
 
            seek_expr_in_expr(heap, stmt.expression, f)
 
        },
 
        _ => None
 
    }
 
}
 
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