operation.rb in glimmer-cs-calculator-1.0.1

- old
+ new

@@ -1,11 +1,26 @@
 module Glimmer
   class Calculator
     class Command
       class Operation < Command
-        # Calculate operation result using number1 and number2 attributes
+        def execute          
+          if number1 && number2 && operation && !last_command.equals?
+            self.result = operation.calculate.to_s            
+            self.number1 = self.result
+          else
+            self.result = last_result || '0'
+            self.operation = self
+          end
+        end
+        
         def calculate
-          raise 'Not implemented! A subclass must implement to calculate operation using number1 and number2 attributes'
+          calculation_result = number1.send(operation_method, number2)
+          calculation_result.to_s.match(/\.0+$/) ? calculation_result.to_i : calculation_result
+        end
+        
+        # Subclasses must implement to indicate operation method on number (e.g. :+ for addition)
+        def operation_method
+          raise 'Not implemented!'
         end
       end
     end
   end
 end