# JOURNAL-lex — Builder

## 2026-06-15 — Initial setup

Phase plan read. Mission: build calc/lexer.py with Token (kind, value), LexError,
and tokenize(src) -> list[Token]. Kinds: NUMBER, PLUS, MINUS, STAR, SLASH, LPAREN,
RPAREN, EOF.

Design notes:
- Token as a dataclass or namedtuple — using dataclass for forward-compat with parser phase
- NUMBER value stored as int if no decimal point, float if decimal present
- LexError carries offending char and position
- tokenize scans left-to-right, skips whitespace, raises on unknown char

## 2026-06-15 — Implementation + local verification

Wrote calc/lexer.py and calc/test_lexer.py. Found one bug in test_values_preserved:
used a conditional expression `('STAR','*') if False else ('PLUS','+')` accidentally
duplicated PLUS in expected list. Fixed immediately.

Test run output:
```
$ python -m unittest -q
----------------------------------------------------------------------
Ran 16 tests in 0.000s

OK
```

Verification commands:
```
$ python -c "from calc.lexer import tokenize; print([(t.kind,t.value) for t in tokenize('3.5*(1-2)')])"
[('NUMBER', 3.5), ('STAR', '*'), ('LPAREN', '('), ('NUMBER', 1), ('MINUS', '-'), ('NUMBER', 2), ('RPAREN', ')'), ('EOF', None)]

$ python -c "from calc.lexer import tokenize; tokenize('1 @ 2')"
calc.lexer.LexError: unexpected character '@' at position 2
```

All D1–D4 criteria met. Claiming all gates.

## 2026-06-15 — Adversary verdicts + AF-1 fix

Adversary returned: D1 PASS, D2 PASS, D3 PASS, D4 PASS.

AF-1 filed (non-blocking): malformed floats (`".."`, `"1.2.3"`, `"."`) raised bare
`ValueError` from `float(raw)` instead of `LexError`. Root cause: greedy dot scanner
at lexer.py:29–31 consumes multi-dot sequences without validation.

Fix: wrapped `float(raw)` in try/except ValueError → re-raise as LexError with
message `"invalid number literal {raw!r} at position {i}"`. Added 3 new tests.

Post-fix run:
```
$ python -m unittest -q
Ran 19 tests in 0.000s
OK
```

Phase DONE.