Changeset - 94751a00b9b7
[Not reviewed]
0 8 0
mh - 4 years ago 2021-05-31 10:43:41
contact@maxhenger.nl
Better error spans for expressions
4 files changed:
0 comments (0 inline, 0 general)
src/protocol/ast.rs
Show inline comments
 
@@ -843,742 +843,774 @@ impl ComponentDefinition {
 
pub struct FunctionDefinition {
 
    pub this: FunctionDefinitionId,
 
    pub defined_in: RootId,
 
    // Symbol scanning
 
    pub builtin: bool,
 
    pub span: InputSpan,
 
    pub identifier: Identifier,
 
    pub poly_vars: Vec<Identifier>,
 
    // Parser
 
    pub return_types: Vec<ParserType>,
 
    pub parameters: Vec<VariableId>,
 
    pub body: BlockStatementId,
 
    // Validation/linking
 
    pub num_expressions_in_body: i32,
 
}
 

	
 
impl FunctionDefinition {
 
    pub(crate) fn new_empty(
 
        this: FunctionDefinitionId, defined_in: RootId, span: InputSpan,
 
        identifier: Identifier, poly_vars: Vec<Identifier>
 
    ) -> Self {
 
        Self {
 
            this, defined_in,
 
            builtin: false,
 
            span, identifier, poly_vars,
 
            return_types: Vec::new(),
 
            parameters: Vec::new(),
 
            body: BlockStatementId::new_invalid(),
 
            num_expressions_in_body: -1,
 
        }
 
    }
 
}
 

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

	
 
impl Statement {
 
    pub fn as_block(&self) -> &BlockStatement {
 
        match self {
 
            Statement::Block(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `BlockStatement`"),
 
        }
 
    }
 
    pub fn as_local(&self) -> &LocalStatement {
 
        match self {
 
            Statement::Local(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `LocalStatement`"),
 
        }
 
    }
 
    pub fn as_memory(&self) -> &MemoryStatement {
 
        self.as_local().as_memory()
 
    }
 
    pub fn as_channel(&self) -> &ChannelStatement {
 
        self.as_local().as_channel()
 
    }
 

	
 
    pub fn as_new(&self) -> &NewStatement {
 
        match self {
 
            Statement::New(result) => result,
 
            _ => panic!("Unable to cast `Statement` to `NewStatement`"),
 
        }
 
    }
 

	
 
    pub fn span(&self) -> InputSpan {
 
        match self {
 
            Statement::Block(v) => v.span,
 
            Statement::Local(v) => v.span(),
 
            Statement::Labeled(v) => v.label.span,
 
            Statement::If(v) => v.span,
 
            Statement::While(v) => v.span,
 
            Statement::Break(v) => v.span,
 
            Statement::Continue(v) => v.span,
 
            Statement::Synchronous(v) => v.span,
 
            Statement::Return(v) => v.span,
 
            Statement::Goto(v) => v.span,
 
            Statement::New(v) => v.span,
 
            Statement::Expression(v) => v.span,
 
            Statement::EndBlock(_) | Statement::EndIf(_) | Statement::EndWhile(_) | Statement::EndSynchronous(_) => unreachable!(),
 
        }
 
    }
 
    pub fn link_next(&mut self, next: StatementId) {
 
        match self {
 
            Statement::Block(stmt) => stmt.next = next,
 
            Statement::EndBlock(stmt) => stmt.next = next,
 
            Statement::Local(stmt) => match stmt {
 
                LocalStatement::Channel(stmt) => stmt.next = next,
 
                LocalStatement::Memory(stmt) => stmt.next = next,
 
            },
 
            Statement::EndIf(stmt) => stmt.next = next,
 
            Statement::EndWhile(stmt) => stmt.next = next,
 
            Statement::EndSynchronous(stmt) => stmt.next = next,
 
            Statement::New(stmt) => stmt.next = next,
 
            Statement::Expression(stmt) => stmt.next = next,
 
            Statement::Return(_)
 
            | Statement::Break(_)
 
            | Statement::Continue(_)
 
            | Statement::Synchronous(_)
 
            | Statement::Goto(_)
 
            | Statement::While(_)
 
            | Statement::Labeled(_)
 
            | Statement::If(_) => unreachable!(),
 
        }
 
    }
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BlockStatement {
 
    pub this: BlockStatementId,
 
    // Phase 1: parser
 
    pub is_implicit: bool,
 
    pub span: InputSpan, // of the complete block
 
    pub statements: Vec<StatementId>,
 
    pub end_block: EndBlockStatementId,
 
    // Phase 2: linker
 
    pub scope_node: ScopeNode,
 
    pub first_unique_id_in_scope: i32, // Temporary fix until proper bytecode/asm is generated
 
    pub next_unique_id_in_scope: i32, // Temporary fix until proper bytecode/asm is generated
 
    pub relative_pos_in_parent: u32,
 
    pub locals: Vec<VariableId>,
 
    pub labels: Vec<LabeledStatementId>,
 
    pub next: StatementId,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct EndBlockStatement {
 
    pub this: EndBlockStatementId,
 
    // Parser
 
    pub start_block: BlockStatementId,
 
    // Validation/Linking
 
    pub next: StatementId,
 
}
 

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

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

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

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

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

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

	
 
#[derive(Debug, Clone)]
 
pub struct EndIfStatement {
 
    pub this: EndIfStatementId,
 
    pub start_if: IfStatementId,
 
    pub next: StatementId,
 
}
 

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

	
 
#[derive(Debug, Clone)]
 
pub struct EndWhileStatement {
 
    pub this: EndWhileStatementId,
 
    pub start_while: WhileStatementId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

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

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

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

	
 
#[derive(Debug, Clone)]
 
pub struct EndSynchronousStatement {
 
    pub this: EndSynchronousStatementId,
 
    pub start_sync: SynchronousStatementId,
 
    // Phase 2: linker
 
    pub next: StatementId,
 
}
 

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

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

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

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

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

	
 
impl ExpressionParent {
 
    pub fn is_new(&self) -> bool {
 
        match self {
 
            ExpressionParent::New(_) => true,
 
            _ => false,
 
        }
 
    }
 

	
 
    pub fn as_expression(&self) -> ExpressionId {
 
        match self {
 
            ExpressionParent::Expression(id, _) => *id,
 
            _ => panic!("called as_expression() on {:?}", self),
 
        }
 
    }
 
}
 

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

	
 
impl Expression {
 
    pub fn as_variable(&self) -> &VariableExpression {
 
        match self {
 
            Expression::Variable(result) => result,
 
            _ => panic!("Unable to cast `Expression` to `VariableExpression`"),
 
        }
 
    }
 

	
 
    pub fn span(&self) -> InputSpan {
 
    /// Returns operator span, function name, a binding's "let" span, etc. An
 
    /// indicator for the kind of expression that is being applied.
 
    pub fn operation_span(&self) -> InputSpan {
 
        match self {
 
            Expression::Assignment(expr) => expr.operator_span,
 
            Expression::Binding(expr) => expr.operator_span,
 
            Expression::Conditional(expr) => expr.operator_span,
 
            Expression::Binary(expr) => expr.operator_span,
 
            Expression::Unary(expr) => expr.operator_span,
 
            Expression::Indexing(expr) => expr.operator_span,
 
            Expression::Slicing(expr) => expr.slicing_span,
 
            Expression::Select(expr) => expr.operator_span,
 
            Expression::Literal(expr) => expr.span,
 
            Expression::Cast(expr) => expr.cast_span,
 
            Expression::Call(expr) => expr.func_span,
 
            Expression::Variable(expr) => expr.identifier.span,
 
        }
 
    }
 

	
 
    /// Returns the span covering the entire expression (i.e. including the
 
    /// spans of the arguments as well).
 
    pub fn full_span(&self) -> InputSpan {
 
        match self {
 
            Expression::Assignment(expr) => expr.span,
 
            Expression::Binding(expr) => expr.span,
 
            Expression::Conditional(expr) => expr.span,
 
            Expression::Binary(expr) => expr.span,
 
            Expression::Unary(expr) => expr.span,
 
            Expression::Indexing(expr) => expr.span,
 
            Expression::Slicing(expr) => expr.span,
 
            Expression::Select(expr) => expr.span,
 
            Expression::Assignment(expr) => expr.full_span,
 
            Expression::Binding(expr) => expr.full_span,
 
            Expression::Conditional(expr) => expr.full_span,
 
            Expression::Binary(expr) => expr.full_span,
 
            Expression::Unary(expr) => expr.full_span,
 
            Expression::Indexing(expr) => expr.full_span,
 
            Expression::Slicing(expr) => expr.full_span,
 
            Expression::Select(expr) => expr.full_span,
 
            Expression::Literal(expr) => expr.span,
 
            Expression::Cast(expr) => expr.span,
 
            Expression::Call(expr) => expr.span,
 
            Expression::Cast(expr) => expr.full_span,
 
            Expression::Call(expr) => expr.full_span,
 
            Expression::Variable(expr) => expr.identifier.span,
 
        }
 
    }
 

	
 
    // TODO: @cleanup
 
    pub fn parent(&self) -> &ExpressionParent {
 
        match self {
 
            Expression::Assignment(expr) => &expr.parent,
 
            Expression::Binding(expr) => &expr.parent,
 
            Expression::Conditional(expr) => &expr.parent,
 
            Expression::Binary(expr) => &expr.parent,
 
            Expression::Unary(expr) => &expr.parent,
 
            Expression::Indexing(expr) => &expr.parent,
 
            Expression::Slicing(expr) => &expr.parent,
 
            Expression::Select(expr) => &expr.parent,
 
            Expression::Literal(expr) => &expr.parent,
 
            Expression::Cast(expr) => &expr.parent,
 
            Expression::Call(expr) => &expr.parent,
 
            Expression::Variable(expr) => &expr.parent,
 
        }
 
    }
 
    // TODO: @cleanup
 
    pub fn parent_expr_id(&self) -> Option<ExpressionId> {
 
        if let ExpressionParent::Expression(id, _) = self.parent() {
 
            Some(*id)
 
        } else {
 
            None
 
        }
 
    }
 

	
 
    pub fn get_unique_id_in_definition(&self) -> i32 {
 
        match self {
 
            Expression::Assignment(expr) => expr.unique_id_in_definition,
 
            Expression::Binding(expr) => expr.unique_id_in_definition,
 
            Expression::Conditional(expr) => expr.unique_id_in_definition,
 
            Expression::Binary(expr) => expr.unique_id_in_definition,
 
            Expression::Unary(expr) => expr.unique_id_in_definition,
 
            Expression::Indexing(expr) => expr.unique_id_in_definition,
 
            Expression::Slicing(expr) => expr.unique_id_in_definition,
 
            Expression::Select(expr) => expr.unique_id_in_definition,
 
            Expression::Literal(expr) => expr.unique_id_in_definition,
 
            Expression::Cast(expr) => expr.unique_id_in_definition,
 
            Expression::Call(expr) => expr.unique_id_in_definition,
 
            Expression::Variable(expr) => expr.unique_id_in_definition,
 
        }
 
    }
 
}
 

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

	
 
#[derive(Debug, Clone)]
 
pub struct AssignmentExpression {
 
    pub this: AssignmentExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub left: ExpressionId,
 
    pub operation: AssignmentOperator,
 
    pub right: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct BindingExpression {
 
    pub this: BindingExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the binding keyword
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub bound_to: ExpressionId,
 
    pub bound_from: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct ConditionalExpression {
 
    pub this: ConditionalExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of question mark operator
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub test: ExpressionId,
 
    pub true_expression: ExpressionId,
 
    pub false_expression: ExpressionId,
 
    // Validator/Linking
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

	
 
#[derive(Debug, Clone)]
 
pub struct BinaryExpression {
 
    pub this: BinaryExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub left: ExpressionId,
 
    pub operation: BinaryOperator,
 
    pub right: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
 
pub enum UnaryOperator {
 
    Positive,
 
    Negative,
 
    BitwiseNot,
 
    LogicalNot,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct UnaryExpression {
 
    pub this: UnaryExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the operator
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub operation: UnaryOperator,
 
    pub expression: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct IndexingExpression {
 
    pub this: IndexingExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub operator_span: InputSpan,
 
    pub full_span: InputSpan,
 
    pub subject: ExpressionId,
 
    pub index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SlicingExpression {
 
    pub this: SlicingExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // from '[' to ']';
 
    pub slicing_span: InputSpan, // from '[' to ']'
 
    pub full_span: InputSpan, // includes subject
 
    pub subject: ExpressionId,
 
    pub from_index: ExpressionId,
 
    pub to_index: ExpressionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct SelectExpression {
 
    pub this: SelectExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the '.'
 
    pub operator_span: InputSpan, // of the '.'
 
    pub full_span: InputSpan, // includes subject and field
 
    pub subject: ExpressionId,
 
    pub field_name: Identifier,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CastExpression {
 
    pub this: CastExpressionId,
 
    // Parsing
 
    pub span: InputSpan, // of the "cast" keyword,
 
    pub cast_span: InputSpan, // of the "cast" keyword,
 
    pub full_span: InputSpan, // includes the cast subject
 
    pub to_type: ParserType,
 
    pub subject: ExpressionId,
 
    // Validator/linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

	
 
#[derive(Debug, Clone)]
 
pub struct CallExpression {
 
    pub this: CallExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub func_span: InputSpan, // of the function name
 
    pub full_span: InputSpan, // includes the arguments and parentheses
 
    pub parser_type: ParserType, // of the function call, not the return type
 
    pub method: Method,
 
    pub arguments: Vec<ExpressionId>,
 
    pub definition: DefinitionId,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

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

	
 
#[derive(Debug, Clone)]
 
pub struct LiteralExpression {
 
    pub this: LiteralExpressionId,
 
    // Parsing
 
    pub span: InputSpan,
 
    pub value: Literal,
 
    // Validator/Linker
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 

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

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

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

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

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

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

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

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

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

	
 
#[derive(Debug, Clone)]
 
pub struct VariableExpression {
 
    pub this: VariableExpressionId,
 
    // Parsing
 
    pub identifier: Identifier,
 
    // Validator/Linker
 
    pub declaration: Option<VariableId>,
 
    pub used_as_binding_target: bool,
 
    pub parent: ExpressionParent,
 
    pub unique_id_in_definition: i32,
 
}
 
\ No newline at end of file
src/protocol/eval/error.rs
Show inline comments
 
use std::fmt;
 

	
 
use crate::protocol::{
 
    ast::*,
 
    Module,
 
    input_source::{ErrorStatement, StatementKind}
 
};
 
use super::executor::*;
 

	
 
/// Represents a stack frame recorded in an error
 
#[derive(Debug)]
 
pub struct EvalFrame {
 
    pub line: u32,
 
    pub module_name: String,
 
    pub procedure: String, // function or component
 
    pub is_func: bool,
 
}
 

	
 
impl fmt::Display for EvalFrame {
 
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 
        let func_or_comp = if self.is_func {
 
            "function "
 
        } else {
 
            "component"
 
        };
 

	
 
        if self.module_name.is_empty() {
 
            write!(f, "{} {}:{}", func_or_comp, &self.procedure, self.line)
 
        } else {
 
            write!(f, "{} {}:{}:{}", func_or_comp, &self.module_name, &self.procedure, self.line)
 
        }
 
    }
 
}
 

	
 
/// Represents an error that ocurred during evaluation. Contains error
 
/// statements just like in parsing errors. Additionally may display the current
 
/// execution state.
 
#[derive(Debug)]
 
pub struct EvalError {
 
    pub(crate) statements: Vec<ErrorStatement>,
 
    pub(crate) frames: Vec<EvalFrame>,
 
}
 

	
 
impl EvalError {
 
    pub(crate) fn new_error_at_expr(prompt: &Prompt, modules: &[Module], heap: &Heap, expr_id: ExpressionId, msg: String) -> EvalError {
 
        // Create frames
 
        debug_assert!(!prompt.frames.is_empty());
 
        let mut frames = Vec::with_capacity(prompt.frames.len());
 
        let mut last_module_source = &modules[0].source;
 
        for frame in prompt.frames.iter() {
 
            let definition = &heap[frame.definition];
 
            let statement = &heap[frame.position];
 
            let statement_span = statement.span();
 

	
 
            let (root_id, procedure, is_func) = match definition {
 
                Definition::Function(def) => {
 
                    (def.defined_in, def.identifier.value.as_str().to_string(), true)
 
                },
 
                Definition::Component(def) => {
 
                    (def.defined_in, def.identifier.value.as_str().to_string(), false)
 
                },
 
                _ => unreachable!("construct stack frame with definition pointing to data type")
 
            };
 

	
 
            // Lookup module name, if it has one
 
            let module = modules.iter().find(|m| m.root_id == root_id).unwrap();
 
            let module_name = if let Some(name) = &module.name {
 
                name.as_str().to_string()
 
            } else {
 
                String::new()
 
            };
 

	
 
            last_module_source = &module.source;
 
            frames.push(EvalFrame{
 
                line: statement_span.begin.line,
 
                module_name,
 
                procedure,
 
                is_func
 
            });
 
        }
 

	
 
        let expr = &heap[expr_id];
 
        let statements = vec![
 
            ErrorStatement::from_source_at_span(StatementKind::Error, last_module_source, expr.span(), msg)
 
            ErrorStatement::from_source_at_span(StatementKind::Error, last_module_source, expr.full_span(), msg)
 
        ];
 

	
 
        EvalError{ statements, frames }
 
    }
 
}
 

	
 
impl fmt::Display for EvalError {
 
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 
        // Display error statement(s)
 
        self.statements[0].fmt(f)?;
 
        for statement in self.statements.iter().skip(1) {
 
            writeln!(f)?;
 
            statement.fmt(f)?;
 
        }
 

	
 
        // Display stack trace
 
        writeln!(f)?;
 
        writeln!(f, " +-  Stack trace:")?;
 
        for frame in self.frames.iter().rev() {
 
            write!(f, " | ")?;
 
            frame.fmt(f)?;
 
            writeln!(f)?;
 
        }
 

	
 
        Ok(())
 
    }
 
}
 
\ No newline at end of file
src/protocol/eval/executor.rs
Show inline comments
 
@@ -206,751 +206,761 @@ pub enum EvalContinuation {
 

	
 
// 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());
 
        let new_frame = Frame::new(heap, def, monomorph_idx);
 
        let max_stack_size = new_frame.max_stack_size;
 
        prompt.frames.push(new_frame);
 
        args.into_store(&mut prompt.store);
 
        prompt.store.reserve_stack(max_stack_size);
 

	
 
        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) => {
 
                            let bind_to = cur_frame.expr_values.pop_back().unwrap();
 
                            let bind_from = cur_frame.expr_values.pop_back().unwrap();
 
                            let bind_to_heap_pos = bind_to.get_heap_pos();
 
                            let bind_from_heap_pos = bind_from.get_heap_pos();
 

	
 
                            let result = apply_binding_operator(&mut self.store, bind_to, bind_from);
 
                            self.store.drop_value(bind_to_heap_pos);
 
                            self.store.drop_value(bind_from_heap_pos);
 
                            cur_frame.expr_values.push_back(Value::Bool(result));
 
                        },
 
                        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) = 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 = match subject {
 
                                        Value::String(v) => *v,
 
                                        Value::Array(v) => *v,
 
                                        Value::Message(v) => *v,
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    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)))
 
                                },
 
                                _ => {
 
                                    // 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 = match &subject {
 
                                        Value::String(v) => *v,
 
                                        Value::Array(v) => *v,
 
                                        Value::Message(v) => *v,
 
                                        _ => unreachable!(),
 
                                    };
 

	
 
                                    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))
 
                                },
 
                            };
 

	
 
                            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)
 
                            enum ValueKind{ Array, String, Message }
 
                            let (value_kind, array_heap_pos) = match deref_subject {
 
                                Value::Array(v) => (ValueKind::Array, *v),
 
                                Value::String(v) => (ValueKind::String, *v),
 
                                Value::Message(v) => (ValueKind::Message, *v),
 
                                _ => unreachable!()
 
                            };
 

	
 
                            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(match value_kind {
 
                                ValueKind::Array => Value::Array(new_heap_pos),
 
                                ValueKind::String => Value::String(new_heap_pos),
 
                                ValueKind::Message => Value::Message(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) => {
 
                            // If we're dealing with a builtin we don't do any
 
                            // fancy shenanigans at all, just push the result.
 
                            match expr.method {
 
                                Method::Get => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value = self.store.maybe_read_ref(&value).clone();
 

	
 
                                    match ctx.get(value.clone(), &mut self.store) {
 
                                        Some(result) => {
 
                                            cur_frame.expr_values.push_back(result)
 
                                        },
 
                                        None => {
 
                                            cur_frame.expr_values.push_front(value.clone());
 
                                            cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                            return Ok(EvalContinuation::BlockGet(value));
 
                                        }
 
                                    }
 
                                },
 
                                Method::Put => {
 
                                    let port_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let deref_port_value = self.store.maybe_read_ref(&port_value).clone();
 
                                    let msg_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let deref_msg_value = self.store.maybe_read_ref(&msg_value).clone();
 

	
 
                                    match deref_msg_value {
 
                                        Value::Message(_) => {},
 
                                        _ => {
 
                                            return Err(EvalError::new_error_at_expr(
 
                                                self, modules, heap, expr_id,
 
                                                String::from("Calls to `put` are currently restricted to only send instances of `msg` types. This will change in the future")
 
                                            ));
 
                                        }
 
                                    }
 

	
 
                                    if ctx.did_put(deref_port_value.clone()) {
 
                                        // We're fine, deallocate in case the expression value stack
 
                                        // held an owned value
 
                                        self.store.drop_value(msg_value.get_heap_pos());
 
                                    } else {
 
                                        cur_frame.expr_values.push_front(msg_value);
 
                                        cur_frame.expr_values.push_front(port_value);
 
                                        cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                        return Ok(EvalContinuation::Put(deref_port_value, deref_msg_value));
 
                                    }
 
                                },
 
                                Method::Fires => {
 
                                    let port_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let port_value_deref = self.store.maybe_read_ref(&port_value).clone();
 
                                    match ctx.fires(port_value_deref.clone()) {
 
                                        None => {
 
                                            cur_frame.expr_values.push_front(port_value);
 
                                            cur_frame.expr_stack.push_back(ExprInstruction::EvalExpr(expr_id));
 
                                            return Ok(EvalContinuation::BlockFires(port_value_deref));
 
                                        },
 
                                        Some(value) => {
 
                                            cur_frame.expr_values.push_back(value);
 
                                        }
 
                                    }
 
                                },
 
                                Method::Create => {
 
                                    let length_value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let length_value = self.store.maybe_read_ref(&length_value);
 
                                    let length = if length_value.is_signed_integer() {
 
                                        let length_value = length_value.as_signed_integer();
 
                                        if length_value < 0 {
 
                                            return Err(EvalError::new_error_at_expr(
 
                                                self, modules, heap, expr_id,
 
                                                format!("got length '{}', can only create a message with a non-negative length", length_value)
 
                                            ));
 
                                        }
 

	
 
                                        length_value as u64
 
                                    } else {
 
                                        debug_assert!(length_value.is_unsigned_integer());
 
                                        length_value.as_unsigned_integer()
 
                                    };
 

	
 
                                    let heap_pos = self.store.alloc_heap();
 
                                    let values = &mut self.store.heap_regions[heap_pos as usize].values;
 
                                    debug_assert!(values.is_empty());
 
                                    values.resize(length as usize, Value::UInt8(0));
 
                                    cur_frame.expr_values.push_back(Value::Message(heap_pos));
 
                                },
 
                                Method::Length => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value_heap_pos = value.get_heap_pos();
 
                                    let value = self.store.maybe_read_ref(&value);
 

	
 
                                    let heap_pos = match value {
 
                                        Value::Array(pos) => *pos,
 
                                        Value::String(pos) => *pos,
 
                                        _ => unreachable!("length(...) on {:?}", value),
 
                                    };
 

	
 
                                    let len = self.store.heap_regions[heap_pos as usize].values.len();
 

	
 
                                    // TODO: @PtrInt
 
                                    cur_frame.expr_values.push_back(Value::UInt32(len as u32));
 
                                    self.store.drop_value(value_heap_pos);
 
                                },
 
                                Method::Assert => {
 
                                    let value = cur_frame.expr_values.pop_front().unwrap();
 
                                    let value = self.store.maybe_read_ref(&value).clone();
 
                                    if !value.as_bool() {
 
                                        return Ok(EvalContinuation::Inconsistent)
 
                                    }
 
                                },
 
                                Method::UserComponent => {
 
                                    // This is actually handled by the evaluation
 
                                    // of the statement.
 
                                    debug_assert_eq!(heap[expr.definition].parameters().len(), cur_frame.expr_values.len());
 
                                    debug_assert_eq!(heap[cur_frame.position].as_new().expression, expr.this)
 
                                },
 
                                Method::UserFunction => {
 
                                    // 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 and reserve its stack size
 
                                    let new_frame = Frame::new(heap, expr.definition, call_data.field_or_monomorph_idx);
 
                                    let new_stack_size = new_frame.max_stack_size;
 
                                    self.frames.push(new_frame);
 
                                    self.store.cur_stack_boundary = new_stack_boundary;
 
                                    self.store.reserve_stack(new_stack_size);
 

	
 
                                    // 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()];
 
                            let ref_value = if expr.used_as_binding_target {
 
                                Value::Binding(variable.unique_id_in_scope as StackPos)
 
                            } else {
 
                                Value::Ref(ValueId::Stack(variable.unique_id_in_scope as StackPos))
 
                            };
 
                            cur_frame.expr_values.push_back(ref_value);
 
                        }
 
                    }
 
                }
 
            }
 
        }
 

	
 
        debug_log!("Frame [{:?}] at {:?}", cur_frame.definition, cur_frame.position);
 
        if debug_enabled!() {
 
            debug_log!("Expression value stack (size = {}):", cur_frame.expr_values.len());
 
            for (_stack_idx, _stack_val) in cur_frame.expr_values.iter().enumerate() {
 
                debug_log!("  [{:03}] {:?}", _stack_idx, _stack_val);
 
            }
 

	
 
            debug_log!("Stack (size = {}):", self.store.stack.len());
 
            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) => {
 
                debug_assert!(stmt.statements.is_empty() || stmt.next == stmt.statements[0]);
 
                cur_frame.position = stmt.next;
 
                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();
 
                let test_value = self.store.maybe_read_ref(&test_value).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();
 
                let test_value = self.store.maybe_read_ref(&test_value).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);
 
                self.store.stack.truncate(self.store.cur_stack_boundary + 1);
 
                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;
 

	
 
                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(); PROPER CLEARING
 
                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/parser/pass_definitions.rs
Show inline comments
 
@@ -480,1505 +480,1539 @@ impl PassDefinitions {
 
            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(),
 
            scope_node: ScopeNode::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(),
 
            next: StatementId::new_invalid(),
 
        });
 

	
 
        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: SynchronousStatementId::new_invalid(),
 
        }))
 
    }
 

	
 
    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(),
 
        }))
 
    }
 

	
 
    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, "an 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)?;
 

	
 
        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 (inner_port_type, end_pos) = 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();
 
            let parser_type = consume_parser_type(
 
                &module.source, iter, &ctx.symbols, &ctx.heap,
 
                poly_vars, SymbolScope::Module(module.root_id), definition_id,
 
                true, 1
 
            )?;
 

	
 
            (parser_type.elements, parser_type.full_span.end)
 
        } else {
 
            // Assume inferred
 
            (
 
                vec![ParserTypeElement{
 
                    element_span: channel_span,
 
                    variant: ParserTypeVariant::Inferred
 
                }],
 
                channel_span.end
 
            )
 
        };
 

	
 
        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 port_type_span = InputSpan::from_positions(channel_span.begin, end_pos);
 
        let port_type_len = inner_port_type.len() + 1;
 
        let mut from_port_type = ParserType{ elements: Vec::with_capacity(port_type_len), full_span: port_type_span };
 
        from_port_type.elements.push(ParserTypeElement{
 
            element_span: channel_span,
 
            variant: ParserTypeVariant::Output,
 
        });
 
        from_port_type.elements.extend_from_slice(&inner_port_type);
 
        let from = ctx.heap.alloc_variable(|this| Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: from_identifier,
 
            parser_type: from_port_type,
 
            relative_pos_in_block: 0,
 
            unique_id_in_scope: -1,
 
        });
 

	
 
        let mut to_port_type = ParserType{ elements: Vec::with_capacity(port_type_len), full_span: port_type_span };
 
        to_port_type.elements.push(ParserTypeElement{
 
            element_span: channel_span,
 
            variant: ParserTypeVariant::Input
 
        });
 
        to_port_type.elements.extend_from_slice(&inner_port_type);
 
        let to = ctx.heap.alloc_variable(|this|Variable{
 
            this,
 
            kind: VariableKind::Local,
 
            identifier: to_identifier,
 
            parser_type: to_port_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: SynchronousStatementId::new_invalid(),
 
        });
 

	
 
        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.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,
 
                    used_as_binding_target: false,
 
                    parent: ExpressionParent::None,
 
                    unique_id_in_definition: -1,
 
                });
 
                let assignment_expr_id = ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                    this,
 
                    span: assign_span,
 
                    operator_span: assign_span,
 
                    full_span: InputSpan::from_positions(memory_span.begin, initial_expr_end_pos),
 
                    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::AtEquals            => Some(AO::Concatenated),
 
                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();
 
            let operator_span = iter.next_span();
 
            iter.consume();
 

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

	
 
            let full_span = InputSpan::from_positions(
 
                ctx.heap[left].full_span().begin,
 
                ctx.heap[right].full_span().end,
 
            );
 

	
 
            Ok(ctx.heap.alloc_assignment_expression(|this| AssignmentExpression{
 
                this, span, left, operation, right,
 
                this, operator_span, full_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();
 
            let operator_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)?;
 

	
 
            let full_span = InputSpan::from_positions(
 
                ctx.heap[test].full_span().begin,
 
                ctx.heap[false_expression].full_span().end,
 
            );
 

	
 
            Ok(ctx.heap.alloc_conditional_expression(|this| ConditionalExpression{
 
                this, span, test, true_expression, false_expression,
 
                this, operator_span, full_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::Tilde) => Some(UO::BitwiseNot),
 
                Some(TK::Exclamation) => Some(UO::LogicalNot),
 
                _ => None
 
            }
 
        }
 

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

	
 
            let expression = self.consume_prefix_expression(module, iter, ctx)?;
 
            let full_span = InputSpan::from_positions(
 
                operator_span.begin, ctx.heap[expression].full_span().end,
 
            );
 
            Ok(ctx.heap.alloc_unary_expression(|this| UnaryExpression {
 
                this,
 
                span,
 
                operation,
 
                expression,
 
                this, operator_span, full_span, operation, expression,
 
                parent: ExpressionParent::None,
 
                unique_id_in_definition: -1,
 
            }).upcast())
 
        } else if next == Some(TokenKind::PlusPlus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix increment is not supported in the language"
 
            ));
 
        } else if next == Some(TokenKind::MinusMinus) {
 
            return Err(ParseError::new_error_str_at_span(
 
                &module.source, iter.next_span(), "prefix decrement is not supported in this language"
 
            ));
 
        } 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();
 
            let mut operator_span = iter.next_span();
 
            iter.consume();
 

	
 
            if token == TokenKind::PlusPlus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, span, "postfix increment is not supported in this language"
 
                    &module.source, operator_span, "postfix increment is not supported in this language"
 
                ));
 
            } else if token == TokenKind::MinusMinus {
 
                return Err(ParseError::new_error_str_at_span(
 
                    &module.source, span, "prefix increment is not supported in this language"
 
                    &module.source, operator_span, "prefix increment is not supported in this language"
 
                ));
 
            } 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;
 
                    operator_span.end = end_span.end;
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, operator_span.end
 
                    );
 

	
 
                    result = ctx.heap.alloc_slicing_expression(|this| SlicingExpression{
 
                        this, span, subject, from_index, to_index,
 
                        this,
 
                        slicing_span: operator_span,
 
                        full_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;
 
                    operator_span.end = end_span.end;
 

	
 
                    let full_span = InputSpan::from_positions(
 
                        ctx.heap[subject].full_span().begin, operator_span.end
 
                    );
 

	
 
                    result = ctx.heap.alloc_indexing_expression(|this| IndexingExpression{
 
                        this, span, subject,
 
                        this, operator_span, full_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)?;
 

	
 
                let full_span = InputSpan::from_positions(
 
                    ctx.heap[subject].full_span().begin, field_name.span.end
 
                );
 
                result = ctx.heap.alloc_select_expression(|this| SelectExpression{
 
                    this, span, subject, field_name,
 
                    this, operator_span, full_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)?;
 
                                let func_span = parser_type.full_span;
 
                                let mut full_span = func_span;
 
                                let arguments = self.consume_expression_list(
 
                                    module, iter, ctx, Some(&mut full_span.end)
 
                                )?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.full_span,
 
                                    this, func_span, full_span,
 
                                    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)?;
 
                                let func_span = parser_type.full_span;
 
                                let mut full_span = func_span;
 
                                let arguments = self.consume_expression_list(
 
                                    module, iter, ctx, Some(&mut full_span.end)
 
                                )?;
 

	
 
                                ctx.heap.alloc_call_expression(|this| CallExpression{
 
                                    this,
 
                                    span: parser_type.full_span,
 
                                    parser_type,
 
                                    method,
 
                                    arguments,
 
                                    this, func_span, full_span, parser_type, method, arguments,
 
                                    definition: target_definition_id,
 
                                    parent: ExpressionParent::None,
 
                                    unique_id_in_definition: -1,
 
                                }).upcast()
 
                            }
 
                        }
 
                    },
 
                    _ => {
 
                        return Err(ParseError::new_error_str_at_span(
 
                            &module.source, parser_type.full_span, "unexpected type in expression"
 
                        ))
 
                    }
 
                }
 
            } 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_LET {
 
                    // Binding expression
 
                    let keyword_span = iter.next_span();
 
                    let operator_span = iter.next_span();
 
                    iter.consume();
 

	
 
                    let bound_to = self.consume_prefix_expression(module, iter, ctx)?;
 
                    consume_token(&module.source, iter, TokenKind::Equal)?;
 
                    let bound_from = self.consume_prefix_expression(module, iter, ctx)?;
 

	
 
                    let full_span = InputSpan::from_positions(
 
                        operator_span.begin, ctx.heap[bound_from].full_span().end,
 
                    );
 

	
 
                    ctx.heap.alloc_binding_expression(|this| BindingExpression{
 
                        this,
 
                        span: keyword_span,
 
                        bound_to,
 
                        bound_from,
 
                        this, operator_span, full_span, bound_to, bound_from,
 
                        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{
 
                                element_span: ident_span,
 
                                variant: ParserTypeVariant::Inferred,
 
                            }],
 
                            full_span: ident_span
 
                        }
 
                    };
 

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

	
 
                    ctx.heap.alloc_cast_expression(|this| CastExpression{
 
                        this,
 
                        span: ident_span,
 
                        to_type,
 
                        subject,
 
                        cast_span: to_type.full_span,
 
                        full_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, component's, or 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,
 
                        used_as_binding_target: false,
 
                        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();
 
            let operator_span = iter.next_span();
 
            iter.consume();
 

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

	
 
            let full_span = InputSpan::from_positions(
 
                ctx.heap[left].full_span().begin,
 
                ctx.heap[right].full_span().end,
 
            );
 

	
 
            result = ctx.heap.alloc_binary_expression(|this| BinaryExpression{
 
                this, span, left, operation, right,
 
                this, operator_span, full_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, @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();
 
        let num_embedded = elements[index].element.variant.num_embedded();
 
        elements.insert(index, Entry{
 
            element: ParserTypeElement{ element_span: span, variant: ParserTypeVariant::Array },
 
            depth,
 
        });
 

	
 
        // Now the original element, and all of its children, should have their
 
        // depth incremented by 1
 
        elements[index + 1].depth += 1;
 
        if num_embedded != 0 {
 
            for idx in index + 2..elements.len() {
 
                let element = &mut elements[idx];
 
                if element.depth >= depth + 1 {
 
                    element.depth += 1;
 
                } else {
 
                    break;
 
                }
 
            }
 
        }
 
    }
 

	
 
    // 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 first_pos = element.element_span.begin;
 
        let mut last_pos = element.element_span.end;
 
        let mut elements = Vec::with_capacity(num_embedded + 2); // type itself + embedded + 1 (maybe) array type
 

	
 
        // Consume any potential array elements
 
        while iter.next() == Some(TokenKind::OpenSquare) {
 
            let mut array_span = iter.next_span();
 
            iter.consume();
 

	
 
            let end_span = iter.next_span();
 
            array_span.end = end_span.end;
 
            consume_token(source, iter, TokenKind::CloseSquare)?;
 

	
 
            last_pos = end_span.end;
 
            elements.push(ParserTypeElement{ element_span: array_span, variant: ParserTypeVariant::Array });
 
        }
 

	
 
        // Push the element itself
 
        let element_span = element.element_span;
 
        elements.push(element);
 

	
 
        // Check if polymorphic arguments are expected
 
        if num_embedded != 0 {
 
            if !allow_inference {
 
                return Err(ParseError::new_error_str_at_span(source, element_span, "type inference is not allowed here"));
 
            }
 

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

	
 
        // When we have applied the initial-open-angle hack (e.g. consuming an
 
        // explicit type on a channel), then we consume the closing angles as
 
        // well.
 
        for _ in 0..first_angle_depth {
 
            let (_, angle_end_pos) = iter.next_positions();
 
            last_pos = angle_end_pos;
 
            consume_token(source, iter, TokenKind::CloseAngle)?;
 
        }
 

	
 
        return Ok(ParserType{
 
            elements,
 
            full_span: InputSpan::from_positions(first_pos, last_pos)
 
        });
 
    };
 

	
 
    // 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();
 
    let first_pos = element.element_span.begin;
 
    let mut last_pos = element.element_span.end;
 
    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 {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    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 {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    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 {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    iter.consume();
 
                    angle_depth -= 1;
 
                    state = State::Close;
 
                } else if Some(TokenKind::ShiftRight) == next {
 
                    let (_, end_angle_pos) = iter.next_positions();
 
                    last_pos = end_angle_pos;
 
                    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.
 
    for idx in 0..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.element_span,
 
                        "type inference is not allowed here"
 
                    ));
 
                }
 

	
 
                // Insert the missing types (in reverse order, but they're all
 
                // of the "inferred" type anyway).
 
                let inserted_span = cur_element.element.element_span;
 
                let inserted_depth = cur_element.depth + 1;
 
                elements.reserve(expected_subtypes);
 
                for _ in 0..expected_subtypes {
 
                    elements.insert(idx + 1, Entry{
 
                        element: ParserTypeElement{ element_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.element_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.element_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.element_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)
 
                    )
 
                ));
 
            }
 
        }
 
    }
 

	
 
    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,
 
        full_span: InputSpan::from_positions(first_pos, last_pos)
 
    })
 
}
 

	
 
/// 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, or the subsequent specification
 
/// of polymorphic arguments.
 
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 {

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