# REVIEW — Phase lex (Adversary)

## Verdicts

### lex/D1: PASS @2026-06-15T05:05Z
Cold-run evidence:
- `tokenize('42')` → `NUMBER 42 int` ✓ (int type confirmed)
- `tokenize('3.14')` → `NUMBER 3.14 float` ✓ (float type confirmed)
- `tokenize('.5')` → `NUMBER 0.5` ✓ (leading dot)
- `tokenize('10.')` → `NUMBER 10.0` ✓ (trailing dot → float)
- EOF appended in all cases ✓

---

### lex/D2: PASS @2026-06-15T05:05Z
Cold-run evidence:
- `tokenize('1+2*3')` → `[('NUMBER', 1), ('PLUS', '+'), ('NUMBER', 2), ('STAR', '*'), ('NUMBER', 3), ('EOF', None)]`
- Matches expected exactly ✓
- All 6 operator/paren kinds verified in test suite ✓

---

### lex/D3: PASS @2026-06-15T05:05Z
Cold-run evidence:
- `tokenize('  12  +  3 ')` → `['NUMBER', 'PLUS', 'NUMBER', 'EOF']` ✓ (spaces skipped)
- `tokenize('1 @ 2')` raises `calc.lexer.LexError: unexpected character '@' at position 2` ✓
  - Offending character `'@'` in message ✓
  - Position `2` in message ✓
- Letters (`abc`), `$` also raise `LexError` per test suite ✓

---

### lex/D4: PASS @2026-06-15T05:05Z
Cold-run evidence:
- `python -m unittest -q` → `Ran 18 tests in 0.000s  OK` ✓
- `tokenize('3.5*(1-2)')` → `[('NUMBER', 3.5), ('STAR', '*'), ('LPAREN', '('), ('NUMBER', 1), ('MINUS', '-'), ('NUMBER', 2), ('RPAREN', ')'), ('EOF', None)]` ✓ (exact plan match)
- `tokenize('1 @ 2')` raises `LexError` (exit 1) ✓
- Required test cases present: `"  12  +  3 "`, `"3.5*(1-2)"`, `"1 @ 2"` ✓
- 18 tests, 0 failures ✓

---

## Adversary findings (non-blocking for this phase)

### AF-1: `ValueError` leaks on malformed number tokens
**Repro:**
```
python -c "from calc.lexer import tokenize; tokenize('1.2.3')"
# → ValueError: could not convert string to float: '1.2.3'

python -c "from calc.lexer import tokenize; tokenize('.')"
# → ValueError: could not convert string to float: '.'
```
The number-scanning loop (`ch.isdigit() or ch == '.'`) greedily consumes all digits and dots, then hands the raw span to `float()` which raises `ValueError` on malformed input like `1.2.3` or bare `.`. These should raise `LexError` for consistency — the caller can't distinguish a lexer malfunction from a Python type error.

**Severity:** Not blocking — the DoD only requires `LexError` for invalid *characters* (`@`, `$`, letters). `1.2.3` and `.` are outside the explicit D1/D3 test cases. However, the parser phase will likely encounter these and must handle them.

**Recommendation:** Wrap the `float(raw)` call in a `try/except ValueError` and re-raise as `LexError`. Flag for builder attention in BUILDER-INBOX.