remove Data2 in favour of Data4

as we write a Marker, type and marker make up 2
so data2 is just the type, not useful

lib/parfait/data_object.rb

@@ -13,8 +13,8 @@
 # logical and math operation that are bundled into the OperatorInstruction.
 #
 # For safe access the access code needs to know the length of the data, which is
-# encoded in the class/type name. Ie An Integer derives from Data2, which is 2 long
-# (minus one for the type, so exactly the one word for the integer)
+# encoded in the class/type name. Ie An Integer derives from Data4, which is 4 long
+# ( one for the type, one for the next, one word for the integer and currently still a marker)
 #
 # DataObjects still have a type, and so can have objects before the data starts
 #
@@ -44,9 +44,9 @@ module Parfait
     end
   end
 
-  class Data2 < DataObject
+  class Data4 < DataObject
     def data_length
-      1
+      3
     end
     def padded_length
       2 * 4

lib/parfait/integer.rb

@@ -7,15 +7,18 @@
 # Ie it would be possible to change the value, we just don't support that)
 
 module Parfait
-  class Integer < Data2
+  class Integer < Data4
 
-    #FIXME: this is "just" for compilation
-    def initialize(value)
+    def initialize(value , next_i = nil)
       super()
       @value = value
+      @next_i = next_i
     end
-    attr_reader :value
+    attr_reader :next_i, :value
 
+    def self.integer_index
+      3 # 1 type, 2 next_i
+    end
     # :integer?, :odd?, :even?, :upto, :downto, :times, :succ, :next, :pred, :chr, :ord, :to_i, :to_int, :floor,
     # :ceil, :truncate, :round, :gcd, :lcm, :gcdlcm, :numerator, :denominator, :to_r, :rationalize,
     # :singleton_method_added, :coerce, :i, :+@, :-@, :fdiv, :div, :divmod, :%, :modulo, :remainder, :abs, :magnitude,
@@ -30,19 +33,19 @@ module Parfait
   end
 
   # adding other base classes in here for now:
-  class FalseClass < Data2
+  class FalseClass < Data4
     #FIXME: this is "just" for compilation
     def initialize
       super
     end
   end
-  class TrueClass < Data2
+  class TrueClass < Data4
     #FIXME: this is "just" for compilation
     def initialize
       super
     end
   end
-  class NilClass < Data2
+  class NilClass < Data4
     #FIXME: this is "just" for compilation
     def initialize
       super

lib/risc/boot.rb

@@ -117,7 +117,7 @@ module Risc
     # superclasses other than default object
     def  super_class_names
        { Object: :Kernel , Kernel: :Value , BinaryCode: :Word ,
-         Data2: :DataObject ,Data8: :DataObject , Integer: :Data2, Word: :Data8}
+         Data4: :DataObject ,Data8: :DataObject , Integer: :Data4, Word: :Data8}
     end
 
     # the function really just returns a constant (just avoiding the constant)
@@ -129,9 +129,9 @@ module Risc
           Message: { next_message: :Message,   receiver: :Object, frame: :NamedList ,
                      return_address: :Integer, return_value: :Integer,
                      caller: :Message ,        name: :Word ,     arguments: :NamedList },
-          Integer: {},
+          Integer: {next_i: :Integer},
           DataObject: {},
-          Data2: {},
+          Data4: {},
           Data8: {},
           TrueClass: {},
           FalseClass: {},

lib/risc/text_writer.rb

@@ -87,7 +87,7 @@ module Risc
         write_String obj
       when Parfait::BinaryCode
         write_BinaryCode obj
-      when Parfait::Data2
+      when Parfait::Data4
         write_data2 obj
       else
         write_object obj
@@ -143,7 +143,7 @@ module Risc
     def write_data2( code )
       @stream.write_signed_int_32( MARKER  )
       write_ref_for( code.get_type )
-      log.debug "Data2 witten stream 0x#{@stream.length.to_s(16)}"
+      log.debug "Data4 witten stream 0x#{@stream.length.to_s(16)}"
     end
 
     def write_BinaryCode( code )