Implement class instance variables

as they are just the type of the meta_class, that was relatively simple.
I feel this is what oo is meant to be, instance variables and methods for the objects, and since classes are objects, for them too.
Class variables seem like a design mistake, weird scoping rules and no data hiding (left as an exercise to the reader)

lib/parfait/class.rb

@@ -33,7 +33,7 @@ module Parfait
       @name = name
       @super_class_name = superclass
       @instance_methods = List.new
-      set_instance_type( instance_type )
+      @instance_type = instance_type
       @meta_class = MetaClass.new( self )
     end
 
@@ -65,13 +65,6 @@ module Parfait
       @instance_type = @instance_type.add_instance_variable( name , type )
     end
 
-    # setting the type generates all methods for this type
-    # (or will do, once we store the methods code to do that)
-    def set_instance_type( type )
-      raise "type must be type #{type}" unless type.is_a?(Type)
-      @instance_type = type
-    end
-
     # return the super class, but raise exception if either the super class name
     # or the super classs is nil.
     # Use only for non Object base class

lib/parfait/meta_class.rb

@@ -30,7 +30,7 @@ module Parfait
       super()
       @clazz = clazz
       @instance_methods = List.new
-      set_instance_type( clazz.get_type() )
+      @instance_type =  Object.object_space.get_type_by_class_name(:Object)
     end
 
     def rxf_reference_name
@@ -61,13 +61,6 @@ module Parfait
       @instance_type = @instance_type.add_instance_variable( name , type )
     end
 
-    # setting the type generates all methods for this type
-    # (or will do, once we store the methods code to do that)
-    def set_instance_type( type )
-      raise "type must be type #{type.class}:#{type}" unless type.is_a?(Type)
-      @instance_type = type
-    end
-
     # Nil name means no superclass, and so nil returned
     def super_class
       return nil

lib/parfait/type.rb

@@ -190,6 +190,7 @@ module Parfait
     def add_instance_variable( name , type )
       raise "No nil name" unless name
       raise "No nil type" unless type
+      return self if @names.index_of(name)
       hash = to_hash
       hash[name] = type
       return Type.for_hash( hash , object_class)