anchor.diff:      (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)))
  +        (set-region-point start end)
           (character-offset start -1)
           (loop
             (unless (search-comment-start-backward end start)
  
positive.code:             (loop
                (when (same-line-p start end)
                  (cond ((space*-p start))
                        (t
                         (insert-string start line-comment)
                         (unless (space*-p end)
  
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)
  