anchor.diff:              (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)
  
positive.code:     (when line-comment
        (with-point ((start (current-point) :right-inserting)
                     (end (current-point) :right-inserting))
          (cond
            ((buffer-mark-p (current-buffer))
             (move-point start (region-beginning))
             (move-point end (region-end)))
            (t
             (line-start start)
             (line-end end)))
          (character-offset start -1)
          (loop
            (unless (search-comment-start-backward end start)
  
negative.code:       (save-excursion
          (with-point ((start (current-point) :right-inserting)
                       (end (current-point) :left-inserting))
            (set-region-point start end)
            (skip-whitespace-forward start)
            (when (point>= start end)
              (insert-string (current-point) line-comment)
  