[patch] factor out comment-or-uncomment feature from comment-dwim

[Benjamin Rutt]

During a discussion today on gnu.emacs.help, I lamented the fact that
only emacs users who were using `transient-mark-mode' could take
advantage of `comment-dwim's ability to detect whether a region is
commented, and uncomment the region if so and comment the region if
not.  I personally don't use `transient-mark-mode', but I would hate
to lose out on `comment-dwim's neat feature just because I don't use
`transient-mark-mode'.

An idea that came out of that discussion was to factor the
comment-or-uncomment feature out of `comment-dwim' and place that code
in a new function named `comment-or-uncomment-region' that would be
callable interactively.  And then have `comment-dwim' make a call to
`comment-or-uncomment-region' in the appropriate place.  But since
`comment-or-uncomment-region' can also be called interactively, this
change would make me very happy because I could gain the "comment or
uncomment" feature of `comment-dwim' without having to use
`transient-mark-mode'.

So I guess the question is, have I convinced the maintainer of
newcomment.el that this change is worthwhile?

BTW, if necessary, I have signed papers for emacs already.  Here
begins the patch, against tonight's cvs:

*** newcomment.el.~1.45.~       Sun Mar  3 20:10:55 2002
--- newcomment.el       Sat Apr  6 22:00:07 2002
***************
*** 893,898 ****
--- 893,911 ----
      (comment-region beg end (+ comment-add arg))))
  
  ;;;###autoload
+ (defun comment-or-uncomment-region (beg end &optional arg)
+   "Call `comment-region', unless the region only consists of comments,
+ in which case call `uncomment-region'.  If a prefix arg is given, it
+ is passed on to the respective function."
+   (interactive "*r\nP")
+   (if (save-excursion ;; check for already commented region
+       (goto-char beg)
+       (comment-forward (point-max))
+       (<= end (point)))
+       (uncomment-region beg end arg)
+     (comment-region beg end arg)))
+ 
+ ;;;###autoload
  (defun comment-dwim (arg)
    "Call the comment command you want (Do What I Mean).
  If the region is active and `transient-mark-mode' is on, call
***************
*** 906,917 ****
    (if (and mark-active transient-mark-mode)
        (let ((beg (min (point) (mark)))
            (end (max (point) (mark))))
!       (if (save-excursion ;; check for already commented region
!             (goto-char beg)
!             (comment-forward (point-max))
!             (<= end (point)))
!           (uncomment-region beg end arg)
!         (comment-region beg end arg)))
      (if (save-excursion (beginning-of-line) (not (looking-at "\\s-*$")))
        ;; FIXME: If there's no comment to kill on this line and ARG is
        ;; specified, calling comment-kill is not very clever.
--- 919,925 ----
    (if (and mark-active transient-mark-mode)
        (let ((beg (min (point) (mark)))
            (end (max (point) (mark))))
!       (comment-or-uncomment-region beg end))
      (if (save-excursion (beginning-of-line) (not (looking-at "\\s-*$")))
        ;; FIXME: If there's no comment to kill on this line and ARG is
        ;; specified, calling comment-kill is not very clever.

-- 
Benjamin