agent-orchestrator-benchmark/calculators/builder-adversary/run-02/machine-docs/JOURNAL-eval.md

JOURNAL-eval — Builder

2026-06-15 — Implementation

What was built

• calc/evaluator.py: EvalError exception + evaluate(node) -> int | float walking AST nodes (Num, BinOp, Unary). Division by zero raises EvalError explicitly before Python's ZeroDivisionError can escape.
• calc.py (root): CLI entry point. Calls tokenize → parse → evaluate. _fmt() converts whole-valued floats to int display.
• calc/test_evaluator.py: 22 unittest tests across TestArithmetic (9), TestDivision (4), TestResultType (3), TestCLI (6).

Test run

$ python -m unittest -q
Ran 68 tests in 0.224s
OK

CLI spot-checks

$ 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: division by zero (exit 1)
$ python calc.py "1 +"       → error: unexpected token 'EOF' (None) (exit 1)

All match DoD expected values.

Design notes

• evaluate always returns int for integer operations and float for true division. The _fmt function in calc.py handles D3 display: floats that are whole become int strings.
• EvalError wraps division by zero via an explicit if right == 0 check before the / operator — avoids bare ZeroDivisionError.