modulize operator_expression

lib/typed/tree/operator_expression.rb

@@ -1,5 +1,7 @@
 module Typed
-  class OperatorExpression < Expression
-    attr_accessor :operator , :left_expression , :right_expression
+  module Tree
+    class OperatorExpression < Expression
+      attr_accessor :operator , :left_expression , :right_expression
+    end
   end
 end

lib/typed/tree/to_code.rb

@@ -96,7 +96,7 @@ module Typed
 
     def on_operator_value statement
       operator , left_e , right_e = *statement
-      w = OperatorExpression.new()
+      w = Tree::OperatorExpression.new()
       w.operator = operator
       w.left_expression = process(left_e)
       w.right_expression = process(right_e)