anchor.diff:                            (available-properties object)))))
   
   ;;;
  -;;; Convenience
  +;;; Property symbol-macro
   ;;;
   (defmacro with-properties (properties object &body body)
     (let ((sh (gensym)))
  
positive.code:   (delete-duplicates (nconc (copy-list (direct-properties object))
                              (mapcan 'available-properties (object-parents object)))))
  
  (defmethod describe-object ((object object) stream)
    (format stream
            "~&Object: ~A~@
  
negative.code:                           (format *query-io* "~&Value to use: ")
                            (list (read *query-io*)))
             value))))
  
  ;;;
  ;;; Value
  