anchor.diff:               :pred (lambda (x) (or (atom x) (eq (car x) refmark))))
       result))
   
  -(defun detect-lost-subtree (routeref-diff base refmark lostmark)
  -  (let ((routeref-lst (construct-routeref-lst routeref-diff refmark)))
  -    (with-route (sub route) base
  -      (cond ((find route routeref-lst :test #'equal) (cons refmark route))
  -            ((find-if (papply (start-with (route-normalize route)
  -                                          (route-normalize _)))
  -                      routeref-lst)
  -             next-level)
  -            (t (cons lostmark route))))))
  -
  -(let* ((base '(lambda (x)
  -                (showdiff *first-impl* *second-impl* x)
  -                (write-line "br/>")))
  -       (modified '(lambda (x)
  -                    (princ x)
  -                    (print (showdiff *first-impl* *second-impl* x)))))
  -  (detect-lost-subtree (rdiff base modified 'ref 1)
  -                              base
  -                              'ref
  -                              'lost))
  -
   (defun lost-subtree-list (routeref-diff base refmark lostmark)
     (let ((routeref-lst (construct-routeref-lst routeref-diff refmark))
           result)
  
positive.code:                 (modified '(lambda (x)
                               (princ x)
                               (print (showdiff *first-impl* *second-impl* x)))))
                 (rdiff base modified 'ref 1)
                 (lost-subtree-list (rdiff base modified 'ref 1) base 'ref 'lost))
  
  (defun blue (x)
    (format t "<font color=\"#0000ff\"> ~a</font>" x))
  
  (defun merge-lost (routeref-diff lost-subtrees refmark)
    (labels ((rec (node route)
  
negative.code:                lost-detected-diff
                 (merge-lost newnode-detected-diff lost-detected-diff 'ref))
  
  (defun output-diff-as-html (base modified &optional (stream *standard-output*) (allowed-distance 1))
    (let* ((*standard-output* stream)
           (refmark (gensym)) (dismark (gensym))
  