lib/dydx/helper.rb in dydx-0.0.5 vs lib/dydx/helper.rb in dydx-0.0.6

@@ -82,9 +82,29 @@
       when :*
         :^
       end
     end
 
+    def sub_ope(operator)
+      case operator
+      when :*
+        :+
+      end
+    end
+
+    def inverse_ope(operator)
+      case operator
+      when :+
+        :-
+      when :*
+        :/
+      end
+    end
+
+    def commutative?(operator)
+      [:+, :*].include?(operator)
+    end
+
     def inverse?(x, operator)
       if is_a?(Algebra::Inverse)
         self.operator == operator && self.x == x
       elsif x.is_a?(Algebra::Inverse)
         self == x.x
\ No newline at end of file