better inspect

lib/parfait/variable.rb

@@ -1,9 +1,19 @@
 module Parfait
   class Variable < Object
+
     def initialize type , name , value = nil
-      @type , @name , @value = type , name , value
-      @value = 0 if @type == :int and value == nil
+      raise "not type #{type}" unless type == :ref or type == :int
+      self.type , self.name , self.value = type , name , value
+      self.value = 0 if self.type == :int and value == nil
+      raise "must give name for variable" unless name
     end
     attributes [:type , :name, :value]
+
+    def to_s
+      "Variable(#{self.type} ,#{self.name})"
+    end
+    def inspect
+      to_s
+    end
   end
 end