Joeven — Learn Autonomous AI Agents

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import ast
import operator

ALLOWED_OPS = {
    ast.Add: operator.add,
    ast.Sub: operator.sub,
    ast.Mult: operator.mul,
    ast.Div: operator.truediv,
    ast.Mod: operator.mod,
    ast.Pow: operator.pow,
    ast.USub: operator.neg,
}

class SandboxError(ValueError):
    pass

def safe_arith(expr):
    tree = ast.parse(expr, mode="eval")

def ev(node):
        if isinstance(node, ast.Expression):
            return ev(node.body)
        if isinstance(node, ast.Constant) and isinstance(node.value, (int, float)):
            return float(node.value)
        if isinstance(node, ast.UnaryOp) and type(node.op) in ALLOWED_OPS:
            return ALLOWED_OPS[type(node.op)](ev(node.operand))
        if isinstance(node, ast.BinOp) and type(node.op) in ALLOWED_OPS:
            return ALLOWED_OPS[type(node.op)](ev(node.left), ev(node.right))
        raise SandboxError("forbidden node: " + type(node).__name__)

return ev(tree)

samples = [
    "(3 + 4) * 10",
    "2 ** 8",
    "__import__('os').system('echo pwned')",
    "open('/etc/passwd').read()",
]
for s in samples:
    try:
        print(s, "->", safe_arith(s))
    except Exception as e:
        print(s, "->", type(e).__name__ + ":", e)

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