anchor.diff:  
   (defvar *buffer-list* '())
   
  +(defun buffer-list ()
  +  "`buffer`のリストを返します。"
  +  *buffer-list*)
  +
  +(defun set-buffer-list (buffer-list)
  +  (setf *buffer-list* buffer-list))
  +
   (defun add-buffer (buffer)
     (check-type buffer buffer)
     (assert (not (get-buffer (buffer-name buffer))))
  -  (push buffer *buffer-list*))
  -
  -(defun buffer-list ()
  -  "`buffer`のリストを返します。"
  -  *buffer-list*)
  +  (set-buffer-list (cons buffer (buffer-list))))
   
   (defun any-modified-buffer-p ()
     (find-if (lambda (buffer)
  
positive.code: (defun unbury-buffer (buffer)
    (check-type buffer buffer)
    (unless (buffer-temporary-p buffer)
      (setf *buffer-list*
            (cons buffer
                  (delete buffer (buffer-list)))))
    buffer)
  
  (defun bury-buffer (buffer)
    "`buffer`をバッファリストの一番最後に移動させ、バッファリストの先頭を返します。"
    (check-type buffer buffer)
    (unless (buffer-temporary-p buffer)
      (setf *buffer-list*
            (nconc (delete buffer (buffer-list))
                   (list buffer))))
    (car (buffer-list)))
  
  (defun get-file-buffer (filename)
  
negative.code:   (alexandria:when-let ((hooks (variable-value 'kill-buffer-hook :global)))
      (run-hooks hooks buffer))
    (buffer-free buffer)
    (set-buffer-list (delete buffer (buffer-list))))
  
  (defun get-next-buffer (buffer)
    "バッファリスト内にある`buffer`の次のバッファを返します。"
  