anchor.diff:  
   ;;; External Interface Routines
   
  -(defun write-cross-links (links &optional (referrer (current-wiki-path)))
  +(defun write-cross-links (links)
     "Write on-disk data of the cross LINKS using specified REFERRER."
  -  (loop with referrer = (wiki-path-to :label referrer)
  -        for referee in (delete-duplicates links :test #'string=)
  +  (loop with referrer = (wiki-path-to :label (current-wiki-path))
  +        for referee in links
           do (let ((content (wiki-content-from :label referee)))
                ;; Ensure WIKI-CONTENT skeleton exists.
  -             (unless (wiki-content-referrers-exist-p content)
  +             (if (not (wiki-content-referrers-exist-p content))
                  (ensure-wiki-content-on-disk-layout content))
                ;; Append cross link to referrers list.
                (unless (member referrer
  
positive.code:     ;; Make second trip.
      (document? (create-parser-context input :attachment attachment))
      (if process-cross-links
          (write-cross-links (context-attachment-links attachment)))
      (get-output-stream-string (context-attachment-output attachment))))
  
  (defmethod markup-to-html ((input wiki-content) &key process-cross-links)
  
negative.code:                              :test #'string=)
                 (push referrer (wiki-content-referrers content))
                 (wiki-content-referrers-update content)))))
  
  (defun remove-abolished-references (current-links)
    "Removes abolished references remained from the previous revision, if any."
    (let ((curr-content (current-wiki-content)))
      ;; If this an initial import, we don't to bother.
      (if (wiki-content-exists-p curr-content)
        (let* ((curr-revision (wiki-content-revision curr-content))
               (prev-content
                (wiki-content-from :path (wiki-content-path curr-content)
                                   (1- curr-revision)))
               (attachment (make-instance
                            'context-attachment
                            :output (make-broadcast-stream)
                            :flags (list 'collect-links)))
               (referrer (wiki-path-to :label (current-wiki-path))))
          ;; Parse file to collect links in the previous revision.
          (document?
           (create-parser-context
            (wiki-content-data-string prev-content)
            :attachment attachment))
          (mapc
           #'(lambda (referee)
               (let ((referee-content (wiki-content-from :label referee)))
                 (when (and (wiki-content-referrers-exist-p referee-content)
                            (member referrer
                                    (wiki-content-referrers referee-content)
                                    :test #'string=))
                   (setf (wiki-content-referrers referee-content)
                         (remove referrer (wiki-content-referrers referee-content)
                                 :test #'string=))
                   (wiki-content-referrers-update referee-content))))
           ;; Collect references that do not exist anymore.
           (set-difference (context-attachment-links attachment) current-links
                           :test #'string=))))))
  
  (defgeneric markup-to-html (input &key process-cross-links)
    (:documentation "Transforms supplied input in wiki markup syntax to HTML."))
  