anchor.diff:    (when pointp
       (setf (marker-point marker) point))
     t)
  -
  -
  -;;; 同じバッファ同士かの比較は保留
   
   (defun marker= (marker1 marker2)
     (assert (eq (marker-buffer marker1)
  
positive.code:       (buffer-add-marker buffer marker))
      marker))
  
  (defun make-marker-current-point (&key (kind :right-inserting) name)
    (make-marker (current-buffer)
                 (current-point)
                 :kind kind
                 :name name))
  
  (defun copy-marker (marker &optional kind)
    (make-marker (marker-buffer marker)
                 (copy-list (marker-point marker))
  
negative.code: (export '(current-marker
            markerp
            make-marker
            copy-marker
            delete-marker
            marker-buffer
  