Merge pull request #13 from Hhamid1991/master

Add subtraction styles to calculator class. Closes #11

sunrise/actions.py

@@ -16,6 +16,7 @@ def __init__(self, operator, a, b):
         self.operator = {
             'Add': '+',
             'Sub': '-',
+            'subtract': '-',
         }[operator] if operator not in self.operators else operator
         self.numbers = [a, b]
 
@@ -30,7 +31,13 @@ def execute(self):
     ),
     (
         re.compile(
-            r'(?P<operator>Add|Sub)\s*(?P<a>\d+)\s*(with|by)\s*(?P<b>\d+)'
+            r'(?P<operator>Add)\s*(?P<a>\d+)\s*(with|by)\s*(?P<b>\d+)'
+        ),
+        Calculator
+    ),
+    (
+        re.compile(
+            r'(?P<operator>Sub|subtract)\s*(?P<b>\d+)\s*(from)\s*(?P<a>\d+)'
         ),
         Calculator
     ),

tests/test_calculator.py

@@ -4,5 +4,7 @@
 def test_parser():
     assert '6' == do('2 + 4')
     assert '6' == do('Add 2 by 4')
+    assert '2' == do('subtract 2 from 4')
+    assert '2' == do('4 - 2')