anchor.diff:                                &key equal min max include-min include-max
                                 (order :ascending)
                                 (id-only nil) (include-subclasses t))
  -  (let ((cache (cache rucksack))
  +  (let ((cache (rucksack-cache rucksack))
           (visited-p (make-hash-table)))
       (labels ((map-slot (class)
                  (let ((index (rucksack-slot-index rucksack class slot
  
positive.code: ;; $Id: rucksack.lisp,v 1.6 2006/05/21 21:00:03 alemmens Exp $
  
  (in-package :rucksack)
  
  
negative.code: (defmethod rucksack-map-class ((rucksack standard-rucksack) class function
                                 &key (id-only nil) (include-subclasses t))
    (let ((visited-p (make-hash-table))
          (cache (rucksack-cache rucksack)))
      (labels ((map-instances (class)
                 (let ((index (rucksack-class-index rucksack class :errorp nil)))
                   (when index
  