types.md

Aver — Key Data Types

Compiler types

Type	Location	Description
TokenKind	src/lexer.rs	Every possible token: literals, keywords, operators, structural (INDENT/DEDENT/NEWLINE/EOF)
Token	src/lexer.rs	TokenKind + source position (line, col)
LexerError	src/lexer.rs	Carry msg, line, col; formatted as "Lexer error [L:C]: msg"
ParseError	src/parser/core.rs	msg, line, col; formatted as "Parse error [L:C]: msg"

AST types

Type	Location	Description
Literal	src/ast.rs	Int(i64), Float(f64), Str(String), Bool(bool)
BinOp	src/ast.rs	Arithmetic and comparison operators as enum variants
Pattern	src/ast.rs	Match arm pattern: Wildcard, Literal, Ident, EmptyList, Cons, Constructor
StrPart	src/ast.rs	Piece of an interpolated string: Literal(String) or Parsed(Box<Expr>)
Expr	src/ast.rs	Every expression form: Literal, Ident, Resolved(u16), Attr, FnCall, BinOp, Match, Constructor, ErrorProp, InterpolatedStr, List(Vec<Expr>), Tuple(Vec<Expr>), MapLiteral(Vec<(Expr, Expr)>), RecordCreate { type_name, fields }, RecordUpdate { type_name, base, updates }, TailCall(Box<(String, Vec<Expr>)>)
Stmt	src/ast.rs	Binding(name, Option<type_ann>, expr), Expr(expr)
FnBody	src/ast.rs	Block(Vec<Stmt>) for parsed source; Expr(Expr) remains as an internal compact form used by some compiler/codegen tests
FnDef	src/ast.rs	Name, params, return type, effects, optional description, body
Module	src/ast.rs	Name + source line, depends, exposes, intent string
VerifyBlock	src/ast.rs	Function name + list of (left_expr, right_expr) equality cases
DecisionBlock	src/ast.rs	Name + source line, date, reason, chosen ref, rejected refs, impacts refs, optional author
DecisionImpact	src/ast.rs	Reusable decision reference: Symbol(String) (validated identifier) or Semantic(String) (free-form text)
TopLevel	src/ast.rs	Top-level item: Module, FnDef, Verify, Decision, Stmt, TypeDef (plus legacy EffectSet placeholder for removed syntax)
TypeDef	src/ast.rs	Sum { name, variants: Vec<TypeVariant> } or Product { name, fields: Vec<(String, String)> }

Runtime types

Type	Location	Description
Value	src/value.rs	Runtime value: Int, Float, Str, Bool, Unit, Ok(Box<Value>), Err(Box<Value>), Some(Box<Value>), None, List(AverList<Value>), Fn{..}, Builtin(String), Variant { type_name, variant, fields }, Record { type_name, fields }, Namespace { name, members }
Env	src/value.rs	Vec<EnvFrame> — scope stack (Owned(HashMap) or Slots(Vec<Rc<Value>>)), innermost last
RuntimeError	src/value.rs	Error enum: Error(String), ErrProp(Box<Value>), TailCall(Box<(String, Vec<Value>)>), ReplayMismatch(String), ReplayExhausted