Expression evaluator (no eval)

glm4-9b

Pythononeshotrun 2sample 030.4s wall

← run 2 · raw JSON · challenge definitions

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deliverables (20%)—

content checks (20%)—

one-shot reply is not valid JSON: Invalid \escape: line 1 column 125 (char 124)

01 what the model was asked

Create calc.py with exactly one public function:

evaluate(expr: str) -> float
    Evaluate an arithmetic expression containing numbers (integers or decimals), the binary operators + - * /, unary minus, parentheses, and arbitrary whitespace. Normal precedence: * and / bind tighter than + and -; operators of equal precedence associate left to right. Division is true division. Examples: evaluate("2+3*4") == 14, evaluate("(2+3)*4") == 20, evaluate("2*-3") == -6.

You must parse the expression yourself: using eval() or exec() is forbidden and is checked by the test suite. Use only the Python standard library.

required deliverables + checks

✗deliverable: calc.py

✗calc.py must contain “def evaluate”

pytest suite it was graded against

test_calc.py · 36 lines · 688 B

from pathlib import Path from calc import evaluate  def test_precedence():    assert evaluate("2+3*4") == 14  def test_parentheses():    assert evaluate("(2+3)*4") == 20    assert evaluate("2*(3+(4-1))") == 12  def test_true_division():    assert evaluate("10/4") == 2.5  def test_left_associativity():    assert evaluate("10-3-2") == 5    assert evaluate("16/4/2") == 2  def test_unary_minus():    assert evaluate("-3+5") == 2    assert evaluate("2*-3") == -6  def test_whitespace_and_decimals():    assert evaluate("  1.5 + 2.25 ") == 3.75  def test_does_not_use_eval():    src = Path("calc.py").read_text()    assert "eval(" not in src    assert "exec(" not in src

02 what it did — full transcript

promptthe exact instruction sent to the model

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You are completing a coding task in one shot. Write complete files that satisfy the spec below. Tests (pytest) will be run against your files; you cannot run them yourself.

Reply with ONE JSON object and nothing else:
{"files": {"<relative path>": "<complete file content>", ...}}

Required deliverable files: calc.py

SPEC:
Create calc.py with exactly one public function:

evaluate(expr: str) -> float
    Evaluate an arithmetic expression containing numbers (integers or decimals), the binary operators + - * /, unary minus, parentheses, and arbitrary whitespace. Normal precedence: * and / bind tighter than + and -; operators of equal precedence associate left to right. Division is true division. Examples: evaluate("2+3*4") == 14, evaluate("(2+3)*4") == 20, evaluate("2*-3") == -6.

You must parse the expression yourself: using eval() or exec() is forbidden and is checked by the test suite. Use only the Python standard library.

reply252 tokens

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```json
{"files": {"calc.py": "import re\n\nclass ExpressionEvaluator:\n    def __init__(self, expr):\n        self.expr = re.sub(r'\s+', '', expr)\n\n    def evaluate(self):\n        return self._evaluate_helper(0, len(self.expr))\n\n    def _evaluate_helper(self, start, end):\n        if start == end:\n            return float(self.expr[start])\n        for i in range(start + 1, end):\n            if self.expr[i] in '+-*/':\n                left = self._evaluate_helper(start, i)\n                right = self._evaluate_helper(i + 1, end)\n                if self.expr[i] == '+':\n                    return left + right\n                elif self.expr[i] == '-':\n                    return left - right\n                elif self.expr[i] == '*':\n                    return left * right\n                elif self.expr[i] == '/':\n                    return left / right\n        raise ValueError('Invalid expression')\n\n\ndef evaluate(expr: str) -> float:\n    evaluator = ExpressionEvaluator(expr)\n    return evaluator.evaluate()"}}

⚠ degenerate outputone-shot reply is not valid JSON: Invalid \escape: line 1 column 125 (char 124)

03 what it wrote

The model produced no files.

04 how it was graded

⚠ degenerate —

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invalid actions

self test runs

252

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30.4s

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