start to add while loop

lib/ast/conditional_expression.rb

@@ -4,7 +4,10 @@ module Ast
     def initialize cond, if_true, if_false
       @cond, @if_true, @if_false = cond, if_true, if_false
     end
-
+    def inspect
+      self.class.name + ".new(" + cond.inspect + ", "+ 
+        if_true.inspect +  ","  + if_false.inspect + " )"  
+    end
     def attributes
       [:cond, :if_true, :if_false]
     end

lib/ast/expression.rb

@@ -37,5 +37,6 @@ end
 
 require_relative "basic_expressions"
 require_relative "conditional_expression"
+require_relative "while_expression"
 require_relative "function_expression"
-require_relative "operator_expressions"
+require_relative "operator_expressions"

lib/ast/while_expression.rb

@@ -0,0 +1,16 @@
+module Ast
+  class WhileExpression < Expression
+    attr_reader  :condition, :body
+    def initialize condition, body
+      @condition , @body = condition , body
+    end
+    def inspect
+      self.class.name + ".new(" + condition.inspect + ", "  + body.inspect + " )"  
+    end
+    def attributes
+      [:condition, :body]
+    end
+  end
+
+  
+end