anchor.diff:  should return the object.
   
   SIZE is the total number of bytes this object consumes."
  -  (setf (gethash name *type-definitions*)
  -	(list name pack-handler unpack-handler size))
  -  nil)
  +	(setf (gethash name *type-definitions*)
  +		  (list name pack-handler unpack-handler size))
  +	nil)
   
   (defun get-type (name)
     "Find the type definition."
  
positive.code:     (funcall unpacker buffer start)))
  
  
  ;; ------ arrays -----------
    
  (defun pack-array (array type buffer start)
    "Pack an array of object into the buffer."
  
negative.code: ;; arrays of structures
  
  ;;
  ;; Strings (fixed-width buffers) are handled in a special (hacky) way
  ;; There should be a better way of doing it.
  ;;
  ;;
  ;; Note that we don't have to concern ourselves with pointers or anything like that.
  ;;
  ;; There is probably a better way of organising some of the code using generic functions,
  ;; particularly for packing/unpacking of the CLOS instances where it seems to make
  ;; the most sense. At the moment we generate a closure at definition time, but this could
  ;; in principle be done using a specialized generic function method.
  ;;
  ;;
  
  ;; alist of type definitions
  