use include so we can test with is_a

using the well documented included/extend trick

lib/parfait/indexed.rb

@@ -8,18 +8,24 @@
 #
 # Using ruby include does not work for similar reasons, so Indexed.at is the main
 # function that generates the methods
+ # ( do have to use a marker module so we can test with is_a?)
 
-module Indexed
+module Parfait
+  module Indexed # marker module
+    def self.included(base)
+      base.extend(Methods)
+    end
 
-  def self.at( offset , clazz )
+    module Methods
+      def offset( offset  )
 
-    clazz.send :define_method , :get_length do
+        define_method  :get_length do
           internal_object_length - 1
         end
 
         # index of item, remeber first item has index 1
         # return  nil if no such item
-    clazz.send :define_method , :index_of do |item|
+        define_method  :index_of do |item|
           max = self.get_length
           counter = 1
           while( counter <= max )
@@ -32,23 +38,23 @@ module Indexed
         end
 
         # include? means non nil index
-    clazz.send :define_method , :include? do |item|
+        define_method  :include? do |item|
           return index_of(item) != nil
         end
 
         # push means add to the end
         # this automatically grows the List
-    clazz.send :define_method , :push do |value|
+        define_method  :push do |value|
           set( self.get_length + 1 , value)
         end
 
-    clazz.send :define_method , :delete do |value|
+        define_method  :delete do |value|
           index = index_of value
           return false unless index
           delete_at index
         end
 
-    clazz.send :define_method , :delete_at do |index|
+        define_method  :delete_at do |index|
           # TODO bounds check
           while(index < self.get_length)
             set( index , get(index + 1))
@@ -59,19 +65,19 @@ module Indexed
         end
 
 
-    clazz.send :define_method , :first do
+        define_method  :first do
           return nil if empty?
           get(1)
         end
 
-    clazz.send :define_method , :last do
+        define_method  :last do
           return nil if empty?
           get(get_length())
         end
 
         # set the value at index.
         # Lists start from index 1
-    clazz.send :define_method , :set do | index , value|
+        define_method  :set do | index , value|
           raise "Only positive indexes #{index}" if index <= 0
           if index > self.get_length
             grow_to(index)
@@ -82,7 +88,7 @@ module Indexed
 
         # set the value at index.
         # Lists start from index 1
-    clazz.send :define_method , :get do | index|
+        define_method  :get do | index|
           raise "Only positive indexes, #{index}" if index <= 0
           if index > self.get_length
             return nil
@@ -91,11 +97,11 @@ module Indexed
           end
         end
 
-    clazz.send :define_method , :empty? do
+        define_method  :empty? do
           self.get_length == 0
         end
 
-    clazz.send :define_method , :set_length do | len|
+        define_method  :set_length do | len|
           was = self.get_length
           return if was == len
           if(was < len)
@@ -105,21 +111,21 @@ module Indexed
           end
         end
 
-    clazz.send :define_method , :grow_to do | len|
+        define_method  :grow_to do | len|
           raise "Only positive lenths, #{len}" if len < 0
           old_length = self.get_length
           return if old_length >= len
           internal_object_grow(len + 1)
         end
 
-    clazz.send :define_method , :shrink_to do | len|
+        define_method  :shrink_to do | len|
           raise "Only positive lenths, #{len}" if len < 0
           old_length = self.get_length
           return if old_length <= len
           internal_object_shrink(len + 1)
         end
 
-    clazz.send :define_method , :equal? do | other|
+        define_method  :equal? do | other|
           # this should call parfait get_class, alas that is not implemented yet
           return false if other.class != self.class
           return false if other.get_length != self.get_length
@@ -134,7 +140,7 @@ module Indexed
         # above, correct, implementation causes problems in the machine object space
         # because when a second empty (newly created) list is added, it is not actually
         # added as it exists already. TODO, but hack with below identity function
-    clazz.send :define_method , :== do | other|
+        define_method  :== do | other|
           self.object_id == other.object_id
         end
 
@@ -143,15 +149,15 @@ module Indexed
         # This is off course 0 for a list, unless someone squeezed an instance variable in
         # but additionally, the amount of data comes on top.
         # unfortuntely we can't just use super because of the Padding
-    clazz.send :define_method , :word_length do
+        define_method  :word_length do
           padded_words( get_layout().get_length() +  get_length() )
         end
 
-    clazz.send :define_method , :inspect do
+        define_method  :inspect do
           inspect_from 1
         end
 
-    clazz.send :define_method , :inspect_from do |index|
+        define_method  :inspect_from do |index|
           ret = ""
           while index <= self.get_length
             item = get(index)
@@ -164,3 +170,5 @@ module Indexed
 
       end
     end
+  end
+end

lib/parfait/layout.rb

@@ -21,7 +21,22 @@
 # Together they turn the object into a hash like structure
 
 module Parfait
-  class Layout < List
+  class Layout < Object
+    include Indexed
+    self.offset(0)
+
+    def each
+      # not sure how to do this with define_method, because of the double block issue.
+      # probably some clever way around that, but not important
+      index = 1
+      while index <= self.get_length
+        item = get(index)
+        yield item
+        index = index + 1
+      end
+      self
+    end
+
     attribute :object_class
 
     def initialize( object_class )

lib/parfait/list.rb

@@ -14,7 +14,8 @@ require_relative "indexed"
 
 module Parfait
   class List < Object
-    Indexed.at(0 , self)
+    include Indexed
+    self.offset(0)
 
     def initialize(  )
       super()

lib/register/assembler.rb

@@ -168,7 +168,7 @@ module Register
       end
       #puts "layout length=#{layout.get_length.to_s(16)} mem_len=#{layout.word_length.to_s(16)}"
       l = layout.get_length
-      if( object.is_a? Parfait::List)
+      if( object.is_a? Parfait::Indexed)
         object.each do |inst|
           write_ref_for(inst)
         end

lib/register/collector.rb

@@ -27,7 +27,7 @@ module Register
         inst = object.get_instance_variable name
         keep(inst , depth + 1)
       end
-      if object.is_a? Parfait::List
+      if object.is_a? Parfait::Indexed
         object.each do |item|
           #puts "Keep item "
           keep(item , depth + 1)

test/parfait/test_list.rb

@@ -6,6 +6,10 @@ class TestList < MiniTest::Test
     Register.machine.boot unless Register.machine.booted
     @list = ::Parfait::List.new
   end
+  def test_isa
+    assert @list.is_a? Parfait::List
+    assert @list.is_a? Parfait::Indexed
+  end
   def test_old_layout
     assert_equal Parfait::Layout , Register.machine.space.classes.keys.get_layout.class
   end