## DONE

Phase: eval — evaluator + CLI
All DoD items self-certified (BUILD phase — deferred Adversary review).

---

### Files created

- `calc/evaluator.py` — `EvalError`, `evaluate(node) -> int | float`
- `calc.py` — top-level CLI
- `calc/test_evaluator.py` — 22 new unittest tests covering D1–D4

---

### D1 — arithmetic

WHAT: `evaluate(parse(tokenize(s)))` correct for `+`, `-`, `*`, `/`, precedence, parens, unary minus.
HOW:
```
python calc.py "2+3*4"    # → 14
python calc.py "(2+3)*4"  # → 20
python calc.py "8-3-2"    # → 3
python calc.py "-2+5"     # → 3 (requires shell quoting awareness)
python calc.py "2*-3"     # → -6
```
EXPECTED: outputs above
WHERE: calc/evaluator.py `evaluate()`

---

### D2 — division

WHAT: `/` is true division; division by zero raises `EvalError`.
HOW:
```
python calc.py "7/2"   # → 3.5
python calc.py "1/0"   # → stderr error, exit 1
```
EXPECTED: `3.5` for 7/2; non-zero exit + stderr for 1/0
WHERE: calc/evaluator.py BinOp `/` branch

---

### D3 — result type

WHAT: Whole-valued → int (no `.0`), non-whole → float.
HOW:
```
python calc.py "4/2"   # → 2  (not 2.0)
python calc.py "7/2"   # → 3.5
```
EXPECTED: `2` and `3.5`
WHERE: calc/evaluator.py — `if isinstance(result, float) and result == int(result): return int(result)`

---

### D4 — CLI

WHAT: `python calc.py "2+3*4"` → `14`, exit 0; error → stderr, non-zero exit, no traceback.
HOW:
```
python calc.py "2+3*4"   # → 14, exit 0
python calc.py "1 +"     # → error to stderr, exit 1
```
EXPECTED: as above
WHERE: calc.py `main()`

---

### D5 — tests green + end-to-end

WHAT: Full test suite (lex + parse + eval) passes; 0 failures.
HOW: `python -m unittest -q`
EXPECTED:
```
Ran 56 tests in 0.226s
OK
```
WHERE: calc/test_lexer.py (14) + calc/test_parser.py (20) + calc/test_evaluator.py (22)

---

### Verify commands (from eval.md, verbatim)

```bash
python -m unittest -q                # Ran 56 tests in ...s  OK
python calc.py "2+3*4"              # 14
python calc.py "(2+3)*4"            # 20
python calc.py "7/2"                # 3.5
python calc.py "4/2"                # 2
python calc.py "1/0"                # error to stderr, non-zero exit
python calc.py "1 +"                # error to stderr, non-zero exit
```

Commit: (see git log — latest commit on main)