Support the python math library

Author: githejie

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mcp-server-calculator"
-version = "0.1.1"
+version = "0.2.0"
 description = "A Model Context Protocol server for calculating"
 readme = "README.md"
 requires-python = ">=3.10"

src/mcp_server_calculator/calculator.py

@@ -1,5 +1,6 @@
 import ast
 import operator
+import math
 from mcp.server.fastmcp import FastMCP
 
 def evaluate(expression: str) -> str:
@@ -13,17 +14,34 @@ def evaluate(expression: str) -> str:
         ast.Pow: operator.pow,
         ast.USub: operator.neg,
     }
+    allowed_names = {
+        k: getattr(math, k)
+        for k in dir(math)
+        if not k.startswith("__")
+    }
+    allowed_names.update({
+        "pi": math.pi,
+        "e": math.e,
+    })
 
     def eval_expr(node):
         if isinstance(node, ast.Constant):
             return node.value
+        elif isinstance(node, ast.Name):
+            if node.id in allowed_names:
+                return allowed_names[node.id]
+            raise ValueError(f"Unknown identifier: {node.id}")
         elif isinstance(node, ast.BinOp):
             left = eval_expr(node.left)
             right = eval_expr(node.right)
             if type(node.op) in allowed_operators:
                 return allowed_operators[type(node.op)](left, right)
         elif isinstance(node, ast.UnaryOp) and isinstance(node.op, ast.USub):
             return -eval_expr(node.operand)
+        elif isinstance(node, ast.Call):
+            func = eval_expr(node.func)
+            args = [eval_expr(arg) for arg in node.args]
+            return func(*args)
         raise ValueError(f"Unsupported operation: {ast.dump(node)}")
 
     expression = expression.replace('^', '**').replace('×', '*').replace('÷', '/')

tests/test_calculator.py

@@ -1,3 +1,4 @@
+import math
 import unittest
 from src.mcp_server_calculator.calculator import evaluate
 
@@ -79,5 +80,20 @@ def test_modulus_by_zero(self):
         with self.assertRaises(ZeroDivisionError):
             evaluate("1 % 0")
 
+    def test_math_functions(self):
+        self.assertAlmostEqual(float(evaluate("sin(pi/2)")), math.sin(math.pi/2), places=7)
+        self.assertAlmostEqual(float(evaluate("cos(0)")), math.cos(0), places=7)
+        self.assertAlmostEqual(float(evaluate("sqrt(16)")), math.sqrt(16), places=7)
+        self.assertAlmostEqual(float(evaluate("log(e)")), math.log(math.e), places=7)
+        self.assertAlmostEqual(float(evaluate("exp(1)")), math.exp(1), places=7)
+        self.assertAlmostEqual(float(evaluate("tan(0)")), math.tan(0), places=7)
+        self.assertAlmostEqual(float(evaluate("fabs(-5)")), math.fabs(-5), places=7)
+        self.assertAlmostEqual(float(evaluate("factorial(5)")), math.factorial(5), places=7)
+        self.assertAlmostEqual(float(evaluate("pow(2, 5)")), math.pow(2, 5), places=7)
+        self.assertAlmostEqual(float(evaluate("degrees(pi)")), math.degrees(math.pi), places=7)
+        self.assertAlmostEqual(float(evaluate("radians(180)")), math.radians(180), places=7)
+        self.assertAlmostEqual(float(evaluate("pi")), math.pi, places=7)
+        self.assertAlmostEqual(float(evaluate("e")), math.e, places=7)
+
 if __name__ == '__main__':
     unittest.main()