modulize class_field and class_statement

lib/typed/ast/class_statement.rb

@@ -1,9 +1,11 @@
 module Typed
-  class ClassStatement < Statement
-    attr_accessor :name , :derives , :statements
-  end
+  module Tree
+    class ClassStatement < Statement
+      attr_accessor :name , :derives , :statements
+    end
 
-  class ClassField < Statement
-    attr_accessor :name , :type
+    class ClassField < Statement
+      attr_accessor :name , :type
+    end
   end
 end

lib/typed/ast/function_statement.rb

@@ -1,5 +1,7 @@
 module Typed
-  class FunctionStatement < Statement
-    attr_accessor :return_type , :name , :parameters, :statements , :receiver
+  module Tree
+    class FunctionStatement < Statement
+      attr_accessor :return_type , :name , :parameters, :statements , :receiver
+    end
   end
 end

lib/typed/ast/to_code.rb

@@ -13,7 +13,7 @@ module Typed
 
     def on_class statement
       name , derives , statements = *statement
-      w = ClassStatement.new()
+      w = Tree::ClassStatement.new()
       w.name = name
       w.derives = derives.children.first
       w.statements = process(statements)
@@ -22,7 +22,7 @@ module Typed
 
     def on_function  statement
       return_type , name , parameters, statements , receiver = *statement
-      w = FunctionStatement.new()
+      w = Tree::FunctionStatement.new()
       w.return_type = return_type
       w.name = name.children.first
       w.parameters = parameters.to_a.collect do |p|