Skip to main content

Parser

internal/parse. Recursive descent with a Pratt-style operator precedence climber for expressions.

Entry points​

  • parse.File(filename, src) (*ast.File, error) — full file.
  • parse.Expr(...) — single expression (used by tests).

A *ast.File is a list of *ast.FnDecls.

Strategy​

Top-level parsing is straightforward recursive descent: see parseFile → parseFnDecl → parseParams etc. Expressions go through parseExpr → parseBinary(prec) which is a textbook Pratt loop on operator precedences (see Operators).

Postfix forms (calls, casts, index access in the future) go through parsePostfix. Builtin calls (tabulate, scan, iterate_until, each, iterate) are dispatched by name in parsePostfix and constructed as their dedicated AST nodes rather than as generic Call nodes.

AST node types​

internal/ast/ast.go. The major ones:

  • Declarations: FnDecl.
  • Statements: LetStmt.
  • Expressions: IntLit (with TypeSuffix), FloatLit, BoolLit, Ident, BinOp, Unary, Call, Lambda, Block, If, Match, Pipeline, Reduce, TensorLit, RangeExpr, Tabulate, Scan, IterateUntil, Iterate, Each, As.
  • Types: NamedType, TensorType.
  • Patterns: IntPat, BoolPat, BindingPat, WildcardPat.

Every AST node carries a Span and implements exprNode() / stmtNode() / declNode() for type discrimination.

Diagnostics​

Parse errors return *diag.Diagnostic with the offending span and a one-line title. Where applicable, they carry a "help" line pointing at the expected form.