Added possibilities to fraction rules.

src/rules/fractions.py

@@ -28,11 +28,11 @@ def match_constant_division(node):
 
     # 0 / a
     if nominator == 0:
-        p.append(P(node, division_of_zero))
+        p.append(P(node, division_of_zero, (denominator,)))
 
     # a / a
     if nominator == denominator:
-        p.append(P(node, division_by_self))
+        p.append(P(node, division_by_self, (nominator,)))
 
     return p
 
@@ -44,6 +44,9 @@ def division_by_one(root, args):
     return args[0]
 
 
+MESSAGES[division_by_one] = _('Division of {1} by 1 reduces to {1}.')
+
+
 def division_of_zero(root, args):
     """
     0 / a  ->  0
@@ -51,6 +54,9 @@ def division_of_zero(root, args):
     return L(0)
 
 
+MESSAGES[division_of_zero] = _('Division of 0 by {1} reduces to 0.')
+
+
 def division_by_self(root, args):
     """
     a / a  ->  1
@@ -58,6 +64,9 @@ def division_by_self(root, args):
     return L(1)
 
 
+MESSAGES[division_by_self] = _('Division of {1} by {1} reduces to 1.')
+
+
 def match_add_constant_fractions(node):
     """
     1 / 2 + 3 / 4  ->  2 / 4 + 3 / 4  # Equalize denominators
@@ -118,6 +127,10 @@ def equalize_denominators(root, args):
     return nary_node('+', scope)
 
 
+MESSAGES[equalize_denominators] = _('Equalize the denominators of division'
+    ' of {1} by {2}.')
+
+
 def add_nominators(root, args):
     """
     a / b + c / b     ->  (a + c) / b
@@ -145,6 +158,9 @@ def add_nominators(root, args):
     return nary_node('+', scope)
 
 
+MESSAGES[add_nominators] = _('Add nominators of the division of {1} by {2}.')
+
+
 def match_expand_and_add_fractions(node):
     """
     a * b / c + d * b / c      ->  (a + d) * (b / c)

tests/test_rules_fractions.py

@@ -21,11 +21,11 @@ class TestRulesFractions(RulesTestCase):
 
         root = zero / a
         possibilities = match_constant_division(root)
-        self.assertEqualPos(possibilities, [P(root, division_of_zero)])
+        self.assertEqualPos(possibilities, [P(root, division_of_zero, (a,))])
 
         root = a / a
         possibilities = match_constant_division(root)
-        self.assertEqualPos(possibilities, [P(root, division_by_self)])
+        self.assertEqualPos(possibilities, [P(root, division_by_self, (a,))])
 
     def test_division_by_one(self):
         a = tree('a')