anchor.diff:      (format stream "~[empty~:;~:*~D item~:P~]"
               (length (%pqueue-contents object)))))
   
  -(defun priority-queue-maximum (priority-queue)
  +(defun priority-queue-minimum (priority-queue)
     "Return the item in PRIORITY-QUEUE with the largest key."
     (symbol-macrolet ((contents (%pqueue-contents priority-queue)))
       (unless (zerop (length contents))
  -      (heap-maximum contents))))
  +      (heap-minimum contents))))
   
  -(defun priority-queue-extract-maximum (priority-queue)
  +(defun priority-queue-extract-minimum (priority-queue)
     "Remove and return the item in PRIORITY-QUEUE with the largest key."
     (symbol-macrolet ((contents (%pqueue-contents priority-queue))
                       (keyfun (%pqueue-keyfun priority-queue)))
       (unless (zerop (length contents))
  -      (heap-extract-maximum contents :key keyfun :test #'<=))))
  +      (heap-extract-minimum contents :key keyfun :test #'<=))))
   
   (defun priority-queue-insert (priority-queue new-item)
  -  "Add NEW-ITEM to PRIOIRITY-QUEUE."
  +  "Add NEW-ITEM to PRIORITY-QUEUE."
     (symbol-macrolet ((contents (%pqueue-contents priority-queue))
                       (keyfun (%pqueue-keyfun priority-queue)))
       (heap-insert contents new-item :key keyfun :test #'<=)))
  
positive.code:     (decf (fill-pointer heap))
      (heapify heap i :key key :test test)))
  
  (defun heap-extract-maximum (heap &key (key #'identity) (test #'>=))
    (heap-extract heap 0 :key key :test test))
  
  
  
negative.code:         (heapify heap largest :key key :test test)))
      heap))
  
  (defun heap-insert (heap new-item &key (key #'identity) (test #'<=))
    (declare (function key test))
    (flet ((key (obj) (funcall key obj))
           (ge (i j) (funcall test i j)))
  