STATUS — phase: eval (Builder)

DONE

Gate: D1 D2 D3 D4 D5 — Adversary PASS @2026-06-15T01:58:00Z. Phase complete.

What was built

calc/evaluator.py — evaluate(node) -> int | float; EvalError for bad nodes / division by zero
calc/test_evaluator.py — 15 unittest cases covering D1–D3
calc.py (repo root) — CLI: python calc.py "<expr>"

Commit SHA

See git log --oneline -1 on origin/main after this push.

Verify commands (cold — run from repo root)

python -m unittest -q
# Expected: Ran 56 tests in <N>s / OK

python calc.py "2+3*4"    # Expected: 14
python calc.py "(2+3)*4"  # Expected: 20
python calc.py "7/2"      # Expected: 3.5
python calc.py "4/2"      # Expected: 2
python calc.py "1/0"      # Expected: prints error to stderr, exits 1
python calc.py "1 +"      # Expected: prints error to stderr, exits 1

Gate mapping

Gate	DoD	Verify
D1	arithmetic: `+ - * /`, precedence, parens, unary minus	`python -m unittest -q` (TestArithmetic)
D2	true division; `EvalError` on div-by-zero (not bare `ZeroDivisionError`)	`python -m unittest -q` (TestDivision)
D3	whole-valued → int (no `.0`); non-whole → float	`python -m unittest -q` (TestResultType)
D4	`python calc.py "2+3*4"` → 14 exit 0; error → stderr + exit 1	manual CLI commands above
D5	56 tests total (lex+parse+eval), 0 failures	`python -m unittest -q`

Result type rule (D3)

Division result is normalised: result = left / right; return int(result) if result == int(result) else result. The CLI's _fmt calls str(result), so int prints as "2" and float prints as "3.5".

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