anchor.diff:    (handler-bind ((unbound-property 'continue))
       (setf (property-value x 'documentation) new-value)))
   
  -;;; Nicknames
   (defun object-nickname (object)
     "Returns OBJECT's nickname"
     (property-value object 'nickname))
  
positive.code:   ;; Finally, for SETF-compliance, we return the value.
    new-value)
  
  ;;; Object Documentation
  (defmethod documentation ((x object) (doc-type (eql 't)))
    (property-value x 'documentation))
  
  
negative.code:                   (mapcar (fun (list  _ (property-value object _) (property-owner object _)))
                            (available-properties object)))))
  
  ;;;
  ;;; Convenience
  ;;;
  (defmacro with-properties (properties object &body body)
    (let ((sh (gensym)))
      `(let ((,sh ,object))
  