# JOURNAL — eval phase

## Session 1

Implemented evaluator, CLI, and tests in one pass.

### evaluator.py design

`evaluate(node)` recursively walks `Num`, `BinOp`, `Unary` nodes. `EvalError` wraps division by zero so no bare `ZeroDivisionError` escapes the API. `_normalize(value)` converts whole-valued floats to int (satisfying D3).

### Test run

```
$ python -m unittest -q
Ran 69 tests in 0.113s
OK
```

Prior suite had 48 tests (lex+parse); 21 new tests from `test_evaluator.py`.

### CLI manual check

```
$ 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 "8-3-2"   → 3
$ python calc.py "-2+5"    → 3
$ python calc.py "2*-3"    → -6
$ python calc.py "1/0"     → error: division by zero (exit 1)
$ python calc.py "1 +"     → error: unexpected token 'EOF' (exit 1)
```

All match plan-specified expected values.