anchor.diff:                :initarg :s)
        (comparator :initform #'<
                    :initarg :comp-fn
  -                 :accessor heap-comp)
  -     )
  -  )
  +                 :accessor heap-comp)))
   
   (defmethod heap-insert ((h heap) n)
     ;; Insert an item into the heap using the heap's comparator.
  
positive.code:                    :s (fset:with
                         (fset:with (heap-storage h) i0 (fset:@ (heap-storage h) i1))
                         i1 orig0)
                     :comp-fn (heap-comp h))
                     ))
  
  (defmethod heap-bubble ((h heap) (index number))
    ;; Internal: move the item at the specified index up in the heap
  
negative.code:     (if (or (< parent 0)
              (not (funcall (heap-comp h) (fset:@ (heap-storage h) index) (fset:@ (heap-storage h) parent))))
          h
          (heap-bubble (heap-swap h child-index parent) parent))))
  
  (defmethod heap-peek ((h heap))
    ;; Peek at, but don't remove the first item in the heap (E.g. if this is a
  