anchor.diff:  	       (setf (slot-contents slots i)
   		     (eval (cadr (member :initform slot-description))))))))
   
  -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;
   ;;; Make an instance using slot-descriptions
   
  
positive.code:     (apply #'sd-initialize-instance instance slot-descriptions initargs)
      instance))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Function make-instance.  
  
negative.code: 
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; We need a way to bootstrap the entire machinery because there are
  ;;; numerous circular dependencies.  We break some of these cycles by
  ;;; providing a set of functions that work directly on "slot
  ;;; descriptors", by which we mean the raw version of the slot
  ;;; information of a class as provided to the DEFCLASS macro.  We take
  ;;; that information, together with information about superclasses,
  ;;; and compute "effective slot descriptor" for each class metaobject.
  ;;; Of course, we have to make sure that this information is computed
  ;;; in a way consistent with what will eventually be done by the real
  ;;; machinery.  Then, we can use this information to allocate
  ;;; instances (because we know the length of the list of slot
  ;;; descriptors) and initialize instance (we have information about
  ;;; initargs and initforms). 
  ;;;
  ;;; The functions sd-initialize-instance and sd-make-instance are part
  ;;; of this bootstrapping machinery.  Using these, we can create
  ;;; instances of any metaobject class that can be found using
  ;;; FIND-CLASS.  This restriction is minor, because all that has to
  ;;; exist is a standard-instance representing the class metaobject
  ;;; associated with a name.  We can fill in the details later, as we
  ;;; do for STANDARD-CLASS.
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Initialize an instance using slot-descriptions.
  
  