# REVIEW — phase `parse`

## Verdict

review(D1-D6): PASS — all six gates verified cold at a05812d

---

## D1: PASS @2026-06-15T02:10Z

Precedence correct: `*`/`/` bind tighter than `+`/`-` via two-level grammar (`expr` → `_term` → `_unary` → `_primary`).

```
parse(tokenize('1+2*3'))  => BinOp('+', Num(1), BinOp('*', Num(2), Num(3)))  ✓
parse(tokenize('2*3+1'))  => BinOp('+', BinOp('*', Num(2), Num(3)), Num(1))  ✓
parse(tokenize('9-4/2'))  => BinOp('-', Num(9), BinOp('/', Num(4), Num(2)))  ✓
```

## D2: PASS @2026-06-15T02:10Z

Left associativity correct: while-loops in `expr()` and `_term()` accumulate left-to-right.

```
parse(tokenize('8-3-2'))  => BinOp('-', BinOp('-', Num(8), Num(3)), Num(2))  ✓
parse(tokenize('8/4/2'))  => BinOp('/', BinOp('/', Num(8), Num(4)), Num(2))  ✓
parse(tokenize('1+2+3'))  => BinOp('+', BinOp('+', Num(1), Num(2)), Num(3))  ✓
```

## D3: PASS @2026-06-15T02:10Z

Parentheses override precedence via `_primary()` grouping.

```
parse(tokenize('(1+2)*3'))  => BinOp('*', BinOp('+', Num(1), Num(2)), Num(3))  ✓
parse(tokenize('((2+3))'))  => BinOp('+', Num(2), Num(3))                       ✓
```

## D4: PASS @2026-06-15T02:10Z

Unary minus handled at `_unary()`, right-recursive, correct for all cases including nested and post-operator.

```
parse(tokenize('-5'))       => Unary('-', Num(5))                             ✓
parse(tokenize('-(1+2)'))   => Unary('-', BinOp('+', Num(1), Num(2)))        ✓
parse(tokenize('3 * -2'))   => BinOp('*', Num(3), Unary('-', Num(2)))        ✓
parse(tokenize('--5'))      => Unary('-', Unary('-', Num(5)))                 ✓
parse(tokenize('---5'))     => Unary('-', Unary('-', Unary('-', Num(5))))     ✓
parse(tokenize('-(1+2)*3')) => BinOp('*', Unary('-', BinOp('+', Num(1), Num(2))), Num(3)) ✓
```

## D5: PASS @2026-06-15T02:10Z

All five required error cases raise `ParseError` (not any other exception). Adversarial extras also raise correctly.

```
'1 +'  => ParseError ✓
'(1'   => ParseError ✓
'1 2'  => ParseError ✓
')('   => ParseError ✓
''     => ParseError ✓
# additional probes:
'*5'   => ParseError ✓
'()'   => ParseError ✓
'+'    => ParseError ✓
'1+2)' => ParseError ✓
```

## D6: PASS @2026-06-15T02:10Z

`python -m unittest -q` → 30 tests, 0 failures, 0 errors.

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Gates to verify: D1 D2 D3 D4 D5 D6 — all PASS.