lib/models/glimmer/calculator/presenter.rb in glimmer-cs-calculator-1.0.0 vs lib/models/glimmer/calculator/presenter.rb in glimmer-cs-calculator-1.0.1

@@ -1,18 +1,26 @@
 require 'models/glimmer/calculator/command'
 
 module Glimmer
   class Calculator
     class Presenter
+      FORMATTER = {
+        nil   => '0',
+        'NaN' => 'Not a number'
+      }
+    
       attr_accessor :result
       
       def initialize
         self.result = '0'
       end
-  
+      
       def press(button)
         command = Command.for(button)
-        self.result = command.result if command
+        if command
+          new_result = command.result
+          self.result = FORMATTER[new_result] || new_result
+        end
       end
     end
   end
 end