anchor.diff:        (save-excursion
           (with-point ((start (current-point) :right-inserting)
                        (end (current-point) :left-inserting))
  -          (cond
  -            ((buffer-mark-p (current-buffer))
  -             (move-point start (region-beginning))
  -             (move-point end (region-end)))
  -            (t
  -             (line-start start)
  -             (line-end end)))
  +          (set-region-point start end)
             (skip-whitespace-forward start)
             (when (point>= start end)
               (insert-string (current-point) line-comment)
  
positive.code:     (skip-whitespace-forward point t)
      (end-line-p point)))
  
  (define-command comment-or-uncomment-region (arg) ("P")
    (if arg
        (uncomment-region)
        (comment-region)))
  
  (define-command comment-region () ()
    (let ((line-comment (or (variable-value 'insertion-line-comment :buffer)
  
negative.code:             (loop
                (when (same-line-p start end)
                  (cond ((space*-p start))
                        ((indentation-point-p end))
                        (t
                         (insert-string start line-comment)
                         (unless (space*-p end)
  