anchor.diff:                   (acond ((equal mnode bnode)
                            (booking-as-ref rroute bnode cont))
                           ((find-ref-candidates mnode rroute allowed-distance base)
  -                         (list (booking-as-lost rroute bnode)
  +                         (list (booking-as-lost rroute bnode cont)
                                  (booking-as-ref it mnode cont rroute)))
                           ((and (not (proper-list-p bnode)) (not (proper-list-p mnode)))
  -                         (list (booking-as-lost rroute bnode)
  +                         (list (booking-as-lost rroute bnode cont)
  +                               mnode))
  +                        ((not (proper-list-p bnode))
  +                         (list (booking-as-lost rroute bnode nil)
  +                               next-level))
  +                        ((not (proper-list-p mnode))
  +                         (list (booking-as-lost rroute bnode cont)
                                  mnode))
                           (t next-level)))
                   ((invalid-p bnode)
  
positive.code:                                        (car (push (route-booking refmark cited node cont) modbook)))
                                        ((eq mark citedmark) (funcall cont)))))
                     (stack-ref-booking cited node cont cur))))
               (booking-as-lost (rroute node)
                 (multiple-value-bind (booking relation mark)
                   (check-booking rroute basebook)
                   (if booking
                     (case relation
                       (:direct (cond ((eq mark citedmark) booking)
                                      (t (error t "~&Something wrong!~%"))))
                       (t (error t "~&Something wrong!~%")))
                     (car (push (route-booking lostmark rroute node) basebook)))))
               (stack-ref-booking (cited node cont cur)
                 (and cur (push (route-booking citedmark cur node nil cited) basebook))
  
negative.code:                         ((proper-list-p mnode) next-level)
                          (t (list mnode))))
                  ((invalid-p mnode)
                   (booking-as-lost rroute bnode cont))))))))
  
  (defun refnode-p (node refmark)
    (and (proper-list-p node) (eq (car node) refmark)))
  