diff --git a/lib/bosl/compiler/callsite_expression.rb b/lib/bosl/compiler/callsite_expression.rb
index 72ddcbfc..4a2859a9 100644
--- a/lib/bosl/compiler/callsite_expression.rb
+++ b/lib/bosl/compiler/callsite_expression.rb
@@ -8,13 +8,13 @@ module Bosl
       if receiver
         me = process( receiver.to_a.first  )
       else
-        me = Virtual::Self.new
+        me = Virtual::Self.new :int
       end
       ## need two step process, compile and save to frame
       # then move from frame to new message
       method.source.add_code Virtual::NewMessage.new
       method.source.add_code Virtual::Set.new( me , Virtual::NewSelf.new(me.type))
-      method.source.add_code Virtual::Set.new( name.to_sym , Virtual::NewMessageName.new())
+      method.source.add_code Virtual::Set.new( name.to_sym , Virtual::NewMessageName.new(:int))
       compiled_args = []
       arguments.to_a.each_with_index do |arg , i|
         #compile in the running method, ie before passing control
diff --git a/lib/bosl/compiler/function_expression.rb b/lib/bosl/compiler/function_expression.rb
index 3615b7f4..18dfc83c 100644
--- a/lib/bosl/compiler/function_expression.rb
+++ b/lib/bosl/compiler/function_expression.rb
@@ -24,10 +24,10 @@ module Bosl
           end
         end
       else
-        r = Virtual::Self.new()
+        r = Virtual::Self.new(:int)
         class_name = method.for_class.name
       end
-      new_method = Virtual::MethodSource.create_method(class_name, name , args )
+      new_method = Virtual::MethodSource.create_method(class_name, return_type, name , args )
       new_method.source.receiver = r
       new_method.for_class.add_instance_method new_method
 
diff --git a/lib/bosl/compiler/name_expression.rb b/lib/bosl/compiler/name_expression.rb
index f04df405..f8fae00d 100644
--- a/lib/bosl/compiler/name_expression.rb
+++ b/lib/bosl/compiler/name_expression.rb
@@ -9,12 +9,12 @@ module Bosl
         name = expression.to_a.first
         return Virtual::Self.new( Virtual::Reference.new(method.for_class)) if name == :self
         # either an argument, so it's stored in message
-        ret =  Virtual::Return.new
+        ret =  Virtual::Return.new :int
         if( index = method.has_arg(name))
-          method.source.add_code Virtual::Set.new( Virtual::ArgSlot.new(index ) , ret)
+          method.source.add_code Virtual::Set.new( Virtual::ArgSlot.new(:int,index ) , ret)
         else # or a local so it is in the frame
           index = method.ensure_local( name )
-          method.source.add_code Virtual::Set.new(Virtual::FrameSlot.new(index ) , ret )
+          method.source.add_code Virtual::Set.new(Virtual::FrameSlot.new(:int,index ) , ret )
         end
         return ret
       end
diff --git a/lib/bosl/compiler/operator_expressions.rb b/lib/bosl/compiler/operator_expressions.rb
index ebfcd75c..602e744b 100644
--- a/lib/bosl/compiler/operator_expressions.rb
+++ b/lib/bosl/compiler/operator_expressions.rb
@@ -3,7 +3,7 @@ module Bosl
 #    operator attr_reader  :operator, :left, :right
     def on_operator expression
       operator , left , right = *expression
-      Virtual::Return.new()
+      Virtual::Return.new(:int)
     end
 
     def on_assign expression
@@ -11,7 +11,7 @@ module Bosl
       name = name.to_a.first
       v = process(value)
       index = method.ensure_local( name )
-      method.source.add_code Virtual::Set.new(Virtual::FrameSlot.new(index ) , v )
+      method.source.add_code Virtual::Set.new(Virtual::FrameSlot.new(:int,index ) , v )
     end
 
   end
diff --git a/lib/register/builtin/integer.rb b/lib/register/builtin/integer.rb
index 1c0f60a9..2943efec 100644
--- a/lib/register/builtin/integer.rb
+++ b/lib/register/builtin/integer.rb
@@ -4,7 +4,7 @@ module Register
     module Integer
       module ClassMethods
         def plus c
-          plus_function = Virtual::MethodSource.create_method(:Integer,:plus , [:Integer] )
+          plus_function = Virtual::MethodSource.create_method(:Integer,:int,:plus , [:Integer] )
           plus_function.source.return_type = Virtual::Integer
           plus_function.source.receiver = Virtual::Integer
 
@@ -43,7 +43,7 @@ module Register
         # end
 
         def putint context
-          putint_function = Virtual::MethodSource.create_method(:Integer,:putint , [] )
+          putint_function = Virtual::MethodSource.create_method(:Integer,:int,:putint , [] )
           putint_function.source.return_type = Virtual::Integer
           putint_function.source.receiver = Virtual::Integer
           return putint_function
@@ -72,7 +72,7 @@ module Register
         # a hand coded version of the fibonachi numbers
         # not my hand off course, found in the net http://www.peter-cockerell.net/aalp/html/ch-5.html
         def fibo context
-          fibo_function = Virtual::MethodSource.create_method(:Integer,:fibo ,  [] )
+          fibo_function = Virtual::MethodSource.create_method(:Integer,:int,:fibo ,  [] )
           fibo_function.source.return_type = Virtual::Integer
           fibo_function.source.receiver = Virtual::Integer
           return fibo_function
diff --git a/lib/register/builtin/kernel.rb b/lib/register/builtin/kernel.rb
index ee5eea04..c4d9e713 100644
--- a/lib/register/builtin/kernel.rb
+++ b/lib/register/builtin/kernel.rb
@@ -6,7 +6,7 @@ module Register
         # it isn't really a function, ie it is jumped to (not called), exits and may not return
         # so it is responsible for initial setup
         def __init__ context
-          function = Virtual::MethodSource.create_method(:Kernel,:__init__ , [])
+          function = Virtual::MethodSource.create_method(:Kernel,:int,:__init__ , [])
           function.source.return_type = Virtual::Integer
           # no method enter or return (automatically added), remove
           function.source.blocks.first.codes.pop # no Method enter
@@ -25,7 +25,7 @@ module Register
           return function
         end
         def exit context
-          function = Virtual::MethodSource.create_method(:Kernel,:exit , [])
+          function = Virtual::MethodSource.create_method(:Kernel,:int,:exit , [])
           function.source.return_type = Virtual::Integer
           return function
           ret = Virtual::RegisterMachine.instance.exit(function)
@@ -33,7 +33,7 @@ module Register
           function
         end
         def __send context
-          function = Virtual::MethodSource.create_method(:Kernel ,:__send , [] )
+          function = Virtual::MethodSource.create_method(:Kernel,:int ,:__send , [] )
           function.source.return_type = Virtual::Integer
           return function
         end
diff --git a/lib/register/builtin/object.rb b/lib/register/builtin/object.rb
index 3b45e145..94e6bbeb 100644
--- a/lib/register/builtin/object.rb
+++ b/lib/register/builtin/object.rb
@@ -6,7 +6,7 @@ module Register
         # main entry point, ie __init__ calls this
         # defined here as empty, to be redefined
         def main context
-          function = Virtual::MethodSource.create_method(:Object,:main , [])
+          function = Virtual::MethodSource.create_method(:Object, :int , :main , [])
           return function
         end
 
@@ -18,7 +18,7 @@ module Register
         # The at_index is just "below" the api, something we need but don't want to expose,
         # so we can't code the above in ruby
         def _get_instance_variable context , name = Virtual::Integer
-          get_function = Virtual::MethodSource.create_method(:Object,:_get_instance_variable , [  ] )
+          get_function = Virtual::MethodSource.create_method(:Object,:int, :_get_instance_variable , [  ] )
           return get_function
   #         me = get_function.receiver
   #         var_name = get_function.args.first
@@ -39,7 +39,7 @@ module Register
         end
 
         def _set_instance_variable(context , name = Virtual::Integer , value = Virtual::Integer )
-          set_function = Virtual::MethodSource.create_method(:Object,:_set_instance_variable ,[] )
+          set_function = Virtual::MethodSource.create_method(:Object,:int,:_set_instance_variable ,[] )
           return set_function
           # receiver set_function
           # me = set_function.receiver
diff --git a/lib/register/builtin/word.rb b/lib/register/builtin/word.rb
index 0b121885..d972c4a0 100644
--- a/lib/register/builtin/word.rb
+++ b/lib/register/builtin/word.rb
@@ -3,7 +3,7 @@ module Register
     module Word
       module ClassMethods
         def putstring context
-          function = Virtual::MethodSource.create_method(:Word , :putstring , [] )
+          function = Virtual::MethodSource.create_method(:Word,:int , :putstring , [] )
           Kernel.emit_syscall( function , :putstring )
           function
         end
diff --git a/lib/virtual/method_source.rb b/lib/virtual/method_source.rb
index a884286c..fde7c74e 100644
--- a/lib/virtual/method_source.rb
+++ b/lib/virtual/method_source.rb
@@ -34,17 +34,18 @@ module Virtual
     # second, it creates MethodSource and attaches it to the method
     #
     # compile code then works with the method, but adds code tot the info
-    def self.create_method( class_name , method_name , args)
+    def self.create_method( class_name , return_type , method_name , args)
       raise "create_method #{class_name}.#{class_name.class}" unless class_name.is_a? Symbol
       raise "create_method #{method_name}.#{method_name.class}" unless method_name.is_a? Symbol
       clazz = Virtual.machine.space.get_class_by_name class_name
       raise "No such class #{class_name}" unless clazz
+      return_type = Virtual::Type.from_sym return_type
       method = clazz.create_instance_method( method_name , Virtual.new_list(args))
-      method.source = MethodSource.new(method)
+      method.source = MethodSource.new(method , return_type)
       method
     end
     # just passing the method object in for Instructions to make decisions (later)
-    def initialize method , return_type = Virtual::Unknown
+    def initialize method , return_type
       # first block we have to create with .new , as new_block assumes a current
       enter = Block.new( "enter"  , method ).add_code(MethodEnter.new( method ))
       @return_type = return_type
diff --git a/lib/virtual/slots/frame_slot.rb b/lib/virtual/slots/frame_slot.rb
index caa5eb94..25c584bd 100644
--- a/lib/virtual/slots/frame_slot.rb
+++ b/lib/virtual/slots/frame_slot.rb
@@ -4,7 +4,7 @@ module Virtual
 
   # Slots in the Frame are local or temporary variables in a message
   class FrameSlot < Slot
-    def initialize index , type = Unknown, value = nil
+    def initialize index , type , value = nil
       super(type, value)
       @index = index
     end
diff --git a/lib/virtual/slots/message_slot.rb b/lib/virtual/slots/message_slot.rb
index 5bdc052c..3b59536b 100644
--- a/lib/virtual/slots/message_slot.rb
+++ b/lib/virtual/slots/message_slot.rb
@@ -7,7 +7,7 @@ module Virtual
   # The Message has a layout as per the constant above
 
   class MessageSlot < Slot
-    def initialize type = Unknown , value = nil
+    def initialize type  , value = nil
       super(type , value )
     end
     def object_name
@@ -19,28 +19,28 @@ module Virtual
 
   # Return is the return of MessageSlot
   class Return < MessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value  )
     end
   end
 
   # Self is the self in MessageSlot
   class Self < MessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value  )
     end
   end
 
   # MessageName of the current message
   class MessageName < MessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value  )
     end
   end
 
   # NewMessageName of the next message
   class ArgSlot < MessageSlot
-    def initialize index , type = Unknown, value = nil
+    def initialize index , type , value = nil
       @index = index
       super( type , value )
     end
diff --git a/lib/virtual/slots/new_message_slot.rb b/lib/virtual/slots/new_message_slot.rb
index 8d66fbc6..761203c9 100644
--- a/lib/virtual/slots/new_message_slot.rb
+++ b/lib/virtual/slots/new_message_slot.rb
@@ -7,7 +7,7 @@ module Virtual
   # The Message has a layout as per the constant above
 
   class NewMessageSlot < Slot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value )
     end
     def object_name
@@ -19,28 +19,28 @@ module Virtual
 
   # NewReturn is the return of NewMessageSlot
   class NewReturn < NewMessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value  )
     end
   end
 
   # NewSelf is the self of NewMessageSlot
   class NewSelf < NewMessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value  )
     end
   end
 
   # NewMessageName of the next message
   class NewMessageName < NewMessageSlot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super( type , value )
     end
   end
 
   # NewMessageName of the next message
   class NewArgSlot < NewMessageSlot
-    def initialize index , type = Unknown, value = nil
+    def initialize index , type , value = nil
       @index = index
       super( type , value )
     end
diff --git a/lib/virtual/slots/self_slot.rb b/lib/virtual/slots/self_slot.rb
index 97d52324..2f844396 100644
--- a/lib/virtual/slots/self_slot.rb
+++ b/lib/virtual/slots/self_slot.rb
@@ -14,7 +14,7 @@ module Virtual
   #  that object
   #
   class SelfSlot < Slot
-    def initialize type = Unknown, value = nil
+    def initialize type , value = nil
       super
     end
     def object_name
diff --git a/lib/virtual/type.rb b/lib/virtual/type.rb
index e4bec88c..c6eec9c4 100644
--- a/lib/virtual/type.rb
+++ b/lib/virtual/type.rb
@@ -7,6 +7,19 @@ module Virtual
       return false unless other.class == self.class
       return true
     end
+
+    # map from a type sym (currently :int/:ref) to a class of subtype of Type
+    # TODO needs to be made extensible in a defined way.  
+    def self.from_sym type
+      case type
+      when :int
+        Virtual::Integer
+      when :ref
+        Virtual::Reference
+      else
+        raise "No type maps to:#{type}"
+      end
+    end
   end
 
   class Integer < Type
@@ -20,7 +33,4 @@ module Virtual
     attr_reader :of_class
   end
 
-  class Unknown < Type
-  end
-
 end
diff --git a/test/compiler/test_basic.rb b/test/compiler/test_basic.rb
index f0c30888..a79833e5 100644
--- a/test/compiler/test_basic.rb
+++ b/test/compiler/test_basic.rb
@@ -36,7 +36,7 @@ class TestBasic < MiniTest::Test
 
   def test_name
     @string_input    = 'foo '
-    @output = "- Virtual::Return(:type => Virtual::Unknown)"
+    @output = "- Virtual::Return(:type => :int)"
     check
   end