anchor.diff:                                 (header filename)
                                  (h1 () (pcdata "~A" title))
                                  (ul -
  -                                   (loop :for (url text) :in *navigation*
  -                                     :do (li -  (a (:href url) (pcdata "~A" text)))))
  +                                   (loop
  +                                     :for (fn text) :in *navigation*
  +                                     :unless (equalp fn filename)
  +                                     :do (li -  (a (:href (make-url fn)) (pcdata "~A" text)))))
                                  (footer filename)))))))
       ;; ---
       (dolist (doc packdocs)
  
positive.code: "
    (div (:class "menu")
        (p - (loop
               :for (url text) :in entries
               :do (pcdata "   ") (a (:href url) (pcdata "~A" text))
               ;; (pcdata "   ")
               ;; (form (:action url :method "GET")
               ;;       (input (:type "submit" :value text)))
               ))))
  
  (defun header (filename)
    (div (:class "header")
        (navigation-menu (remove (make-url filename) *navigation*
                                 :test (function string=)
                                 :key (function first))))
    (hr) (br))
  
negative.code:              (return
                 (append *navigation*
                         (when prev
                           (list (list prev   (format nil "Previous: ~A" (shorten prev)))))
                         (when next
                           (list (list next   (format nil "Next: ~A" (shorten next)))))
                         (when parent
                           (list (list parent (format nil "Up: ~A" (shorten parent)))))))))
        :finally (return *navigation*))))
  
  
  