agent-orchestrator-benchmark/calculators/builder-adversary-min/run-02/machine-docs/JOURNAL-parse.md

JOURNAL — phase parse

Approach

Recursive-descent parser with standard precedence climbing:

• expr handles + and - (lowest precedence), left-associative via iteration
• _term handles * and / (higher precedence), left-associative via iteration
• _unary handles unary - recursively (right-recursive so --5 works)
• _primary handles numbers and parenthesized subexpressions

Empty input detected early (before _Parser is constructed) by checking if the token list is empty or contains only EOF. This avoids a confusing error path through _primary.

Gate verification results (local)

• D1: 1+2*3 → BinOp('+', Num(1), BinOp('*', Num(2), Num(3))) ✓
• D2: 8-3-2 → BinOp('-', BinOp('-', Num(8), Num(3)), Num(2)) ✓
• D2: 8/4/2 → BinOp('/', BinOp('/', Num(8), Num(4)), Num(2)) ✓
• D3: (1+2)*3 → BinOp('*', BinOp('+', Num(1), Num(2)), Num(3)) ✓
• D4: -5 → Unary('-', Num(5)) ✓
• D4: -(1+2) → Unary('-', BinOp('+', Num(1), Num(2))) ✓
• D4: 3 * -2 → BinOp('*', Num(3), Unary('-', Num(2))) ✓
• D5: all 5 error cases raise ParseError ✓
• D6: 30 tests, 0 failures ✓