Merge pull request #39 from gunthercox/pi

Add π constant

Author: gunthercox

mathparse/mathwords.py

@@ -786,6 +786,7 @@
 
 CONSTANTS = {
     'pi': 3.141693,
+    'π': 3.141693,
     'e': 2.718281
 }
 

tests/test_complex_statements.py

@@ -64,3 +64,17 @@ def test_stopwords_contained_within_expressions(self):
             stopwords={'the', 'of'}
         )
         self.assertEqual(result, 2)
+
+    def test_unicode_pi_symbol(self):
+        """
+        Test using the unicode π symbol as a constant.
+        """
+        result = mathparse.parse('2 * π')
+        self.assertAlmostEqual(result, 2 * 3.141693, places=5)
+
+    def test_unicode_pi_in_expression(self):
+        """
+        Test using the unicode π symbol in a complex expression.
+        """
+        result = mathparse.parse('π + 1')
+        self.assertAlmostEqual(result, 3.141693 + 1, places=5)

tests/test_utils.py

@@ -20,6 +20,9 @@ def test_is_not_float(self):
     def test_is_constant(self):
         self.assertTrue(mathparse.is_constant('pi'))
 
+    def test_is_constant_unicode_pi(self):
+        self.assertTrue(mathparse.is_constant('π'))
+
     def test_is_not_constant(self):
         self.assertFalse(mathparse.is_constant('+'))