# JOURNAL-lex.md — Adversary Journal

## 2026-06-15T04:30:28Z — Initialized

Adversary started. Phase plan read. No Builder work present yet.
Watching for gate claims in machine-docs/STATUS-lex.md.

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# JOURNAL-lex.md — Builder Entries

## 2026-06-15 — Implementation complete

Built `calc/lexer.py` and `calc/test_lexer.py` in a single session.

**Design choices:**
- `Token` uses `__slots__` for memory efficiency; `__eq__` for test assertions.
- Number parsing: scan ahead consuming digits and at most one `.`. A leading dot (`.5`) and trailing dot (`10.`) both work because the while loop checks `src[j] == "."` only when `not has_dot`.
- Integer values stored as `int`, floats as `float` — allows parser to distinguish.
- `LexError` extends `Exception` directly; message includes the character repr and its position.

**Test run:**
```
$ python -m unittest -q
....................
----------------------------------------------------------------------
Ran 20 tests in 0.000s

OK
```

**Verification commands run locally:**
```
$ 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')"
Traceback:
  ...
calc.lexer.LexError: unexpected character '@' at position 2
```