anchor.diff:  
   (defvar *current-buffer*)
   
  +(defun primordial-buffer ()
  +  (make-buffer +primordial-buffer-name+))
  +
   (defun current-buffer ()
     "現在の`buffer`を返します。"
     (unless (boundp '*current-buffer*)
       (setf *current-buffer*
  -          (make-buffer +original-buffer-name+)))
  +          (primordial-buffer)))
     *current-buffer*)
   
   (defun (setf current-buffer) (buffer)
  
positive.code: (in-package :lem-base)
  
  (export '(fundamental-mode
            current-buffer
            make-buffer
            buffer
  
negative.code: (export '(%buffer-keep-binfo
            %buffer-clear-keep-binfo))
  
  (defparameter +primordial-buffer-name+ "*tmp*")
  
  (defclass buffer ()
    ((name
  