agent-orchestrator-benchmark/calculators/builder-adversary-stateless/run-03/machine-docs/JOURNAL-parse.md

JOURNAL — Phase parse (Builder)

2026-06-15 — Implementation

Design decisions

• Grammar: expr → term ((+|-) term)*, term → unary ((*|/) unary)*, unary → - unary | primary, primary → NUMBER | ( expr ). Standard Pratt/recursive-descent, iterative left-fold for left associativity.
• Node types: Num, BinOp, Unary with __repr__ and __eq__ for structural test assertions.
• ParseError defined in parser.py.

Test run output

$ python -m unittest -q
Ran 44 tests in 0.001s
OK

Cold-verify commands verified locally

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('1+2*3')))"
BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; parse(tokenize('1 +'))"
calc.parser.ParseError: unexpected token 'EOF' (None)
(exit 1)

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('8-3-2')))"
BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('8/4/2')))"
BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('(1+2)*3')))"
BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('-5')))"
Unary('-', Num(5))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('-(1+2)')))"
Unary('-', BinOp('+', Num(1), Num(2)))

$ python -c "from calc.lexer import tokenize; from calc.parser import parse; print(parse(tokenize('3 * -2')))"
BinOp('*', Num(3), Unary('-', Num(2)))