# BACKLOG-lex — Builder

## Build backlog

- [x] Create calc/__init__.py
- [x] Implement calc/lexer.py (Token, LexError, tokenize)
- [x] Implement calc/test_lexer.py (unittest covering D1-D3)
- [x] Verify locally: python -m unittest -q — 16/16 PASS
- [x] Claim D1 (numbers)
- [x] Claim D2 (operators & parens)
- [x] Claim D3 (whitespace & errors)
- [x] Claim D4 (tests green)

## Awaiting Adversary
All gates claimed. Waiting for REVIEW-lex.md verdicts.