pretty much redid the variable idea (now slot)

lib/virtual/slot.rb

@@ -0,0 +1,65 @@
+module Virtual
+  # Slots are named, or rather indexed, storage locations that are typed.
+  # Four of those locations exist and those correspond to subclasses:
+  # - the message that has been received: MessageSlot
+  # - the frame of the method that is executing (local variables): FrameSlot
+  # - self as an object: SelfSlot
+  # - a message that will be sent, NewMessageSlot
+  
+  # additionally frame, self and return are slots in Message and NewMessage
+
+  class Slot < Value
+    RETURN = 0
+    SELF = 1
+
+    attr_accessor :index , :type
+    private #abstract base class
+    def initialize index , type
+      @index = index
+      @type = type
+    end
+  end
+  
+  class MessageSlot < Slot
+    def initialize index , type = Mystery
+      super
+    end
+  end
+  class FrameSlot < Slot
+    def initialize index , type = Mystery
+      super
+    end
+  end
+  class SelfSlot < Slot
+    def initialize index , type = Mystery
+      super
+    end
+  end
+  class NewMessageSlot < Slot
+    def initialize index , type = Mystery
+      super
+    end
+  end
+
+  class Return < MessageSlot
+    def initialize type = Mystery
+      super( RETURN , type )
+    end
+  end
+  class NewReturn < NewMessageSlot
+    def initialize type = Mystery
+      super( RETURN , type )
+    end
+  end
+  class Self < MessageSlot
+    def initialize type = Mystery
+      super( SELF , type )
+    end
+  end
+  class NewSelf < NewMessageSlot
+    def initialize type = Mystery
+      super( SELF , type )
+    end
+  end
+
+end