Merge pull request #34 from flotwig/allow-abrupt-decimals

Support decimals beginning with only a dot
axiacore · Jun 18, 2018 · e5c2312 · e5c2312
2 parents de41e02 + a7ec301
commit e5c2312
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diff --git a/py_expression_eval/__init__.py b/py_expression_eval/__init__.py
@@ -522,7 +522,9 @@ def isNumber(self):
         while self.pos < len(self.expression):
             code = self.expression[self.pos]
             if (code >= '0' and code <= '9') or code == '.':
-                str += self.expression[self.pos]
+                if (len(str) == 0 and code == '.' ):
+                    str = '0'
+                str += code
                 self.pos += 1
                 self.tokennumber = float(str)
                 r = True

diff --git a/py_expression_eval/tests.py b/py_expression_eval/tests.py
@@ -173,6 +173,18 @@ def count(increment):
         self.assertEqual(parser.evaluate("count(inc)", variables={"inc": 5}), 5)
         self.assertEqual(parser.evaluate("count(inc)", variables={"inc": 5}), 10)
 
+    def test_decimals(self):
+        parser = Parser()
+
+        self.assertEqual(parser.parse(".1").evaluate({}), parser.parse("0.1").evaluate({}))
+        self.assertEqual(parser.parse(".1*.2").evaluate({}), parser.parse("0.1*0.2").evaluate({}))
+        self.assertEqual(parser.parse(".5^3").evaluate({}), float(0.125))
+        self.assertEqual(parser.parse("16^.5").evaluate({}), 4)
+        self.assertEqual(parser.parse("8300*.8").evaluate({}), 6640)
+
+        with self.assertRaises(ValueError):
+            parser.parse("..5").evaluate({})
+
 
 if __name__ == '__main__':
     unittest.main()