64 lines
2.6 KiB
Python
64 lines
2.6 KiB
Python
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"""计算器工具"""
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# ════════════════════════════════════════════════════════════════
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# tools/calculator.py — 数学计算工具
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# ════════════════════════════════════════════════════════════════
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"""
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tools/calculator.py
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安全的数学表达式计算工具（使用 ast 模块避免 eval 注入风险）
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"""
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import ast
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import operator
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from tools.base_tool import BaseTool, ToolResult
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class CalculatorTool(BaseTool):
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name = "calculator"
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description = "计算数学表达式，支持加减乘除、幂运算、括号等"
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parameters = {
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"expression": {
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"type": "string",
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"description": "数学表达式，例如 '(1+2)*3' 或 '2**10'",
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}
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}
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# 允许的运算符白名单（防止注入）
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_OPERATORS = {
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ast.Add: operator.add,
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ast.Sub: operator.sub,
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ast.Mult: operator.mul,
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ast.Div: operator.truediv,
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ast.Pow: operator.pow,
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ast.Mod: operator.mod,
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ast.USub: operator.neg,
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}
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def execute(self, expression: str, **_) -> ToolResult:
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try:
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tree = ast.parse(expression, mode="eval")
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result = self._eval_node(tree.body)
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return ToolResult(
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success=True,
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output=f"{expression} = {result}",
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metadata={"expression": expression, "result": result},
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)
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except (ValueError, TypeError, ZeroDivisionError) as exc:
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return ToolResult(success=False, output=f"计算错误: {exc}")
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def _eval_node(self, node: ast.AST) -> float:
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"""递归解析 AST 节点"""
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match node:
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case ast.Constant(value=v) if isinstance(v, (int, float)):
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return v
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case ast.BinOp(left=left, op=op, right=right):
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fn = self._OPERATORS.get(type(op))
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if fn is None:
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raise ValueError(f"不支持的运算符: {type(op).__name__}")
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return fn(self._eval_node(left), self._eval_node(right))
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case ast.UnaryOp(op=op, operand=operand):
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fn = self._OPERATORS.get(type(op))
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if fn is None:
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raise ValueError(f"不支持的一元运算符: {type(op).__name__}")
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return fn(self._eval_node(operand))
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case _:
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raise ValueError(f"不支持的表达式节点: {type(node).__name__}")
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