# STATUS — phase lex

## DONE

## claim(D1): numbers tokenize correctly

**What:** Integers and floats (including `.5`, `10.`) produce a single `NUMBER` token with the correct numeric type (int or float), followed by `EOF`.

**How to verify:**
```bash
python -c "from calc.lexer import tokenize; toks = tokenize('42'); print(toks[0].kind, toks[0].value, type(toks[0].value).__name__, toks[1].kind)"
python -c "from calc.lexer import tokenize; toks = tokenize('3.14'); print(toks[0].kind, toks[0].value, type(toks[0].value).__name__)"
python -c "from calc.lexer import tokenize; toks = tokenize('.5'); print(toks[0].kind, toks[0].value)"
python -c "from calc.lexer import tokenize; toks = tokenize('10.'); print(toks[0].kind, toks[0].value, type(toks[0].value).__name__)"
```

**Expected:**
```
NUMBER 42 int EOF
NUMBER 3.14 float
NUMBER 0.5 float
NUMBER 10.0 float
```

**Files:** `calc/lexer.py`, `calc/__init__.py`

---

## claim(D2): operators and parens tokenize correctly

**What:** `+ - * / ( )` each produce their respective token kind; `tokenize("1+2*3")` yields `NUMBER PLUS NUMBER STAR NUMBER EOF`.

**How to verify:**
```bash
python -c "from calc.lexer import tokenize; print([t.kind for t in tokenize('1+2*3')])"
python -c "from calc.lexer import tokenize; print([t.kind for t in tokenize('+-*/()')] )"
```

**Expected:**
```
['NUMBER', 'PLUS', 'NUMBER', 'STAR', 'NUMBER', 'EOF']
['PLUS', 'MINUS', 'STAR', 'SLASH', 'LPAREN', 'RPAREN', 'EOF']
```

**Files:** `calc/lexer.py`

---

## claim(D3): whitespace skipped, invalid chars raise LexError

**What:** Spaces/tabs between tokens are silently skipped. Any unrecognized character (e.g. `@`, `$`, letter) raises `LexError` with the offending character and its position in the message.

**How to verify:**
```bash
python -c "from calc.lexer import tokenize; print([t.kind for t in tokenize('  12  +  3 ')])"
python -c "from calc.lexer import tokenize; tokenize('1 @ 2')"
```

**Expected:**
- First command: `['NUMBER', 'PLUS', 'NUMBER', 'EOF']`
- Second command: raises `calc.lexer.LexError: unexpected character '@' at position 2`

**Files:** `calc/lexer.py`

---

## claim(D4): all tests pass

**What:** `calc/test_lexer.py` (15 test cases covering D1–D3, including the three required expressions) passes with 0 failures.

**How to verify:**
```bash
python -m unittest -q
```

**Expected:**
```
Ran 15 tests in 0.000s

OK
```

**Also run the plan's exact cold-verify commands:**
```bash
python -c "from calc.lexer import tokenize; print([(t.kind,t.value) for t in tokenize('3.5*(1-2)')])"
python -c "from calc.lexer import tokenize; tokenize('1 @ 2')"
```

**Expected:**
```
[('NUMBER', 3.5), ('STAR', '*'), ('LPAREN', '('), ('NUMBER', 1), ('MINUS', '-'), ('NUMBER', 2), ('RPAREN', ')'), ('EOF', None)]
Traceback ... LexError: unexpected character '@' at position 2
```

**Files:** `calc/test_lexer.py`