POC comment/uncomment region in nxml-mode

POC comment/uncomment region in nxml-mode

[Tim Chambers]

Here's a POC for interactively commenting/uncommenting a region in
nxml-mode. I guess if I wanted to submit this as an enhancement to
nxml-mode I'd have to properly integrate the functions into nXML mode.
Looking for motivation. Anyone interest in pursuing this?

(defun my-nxml-comment-region ()
  "comment a block if in nXML mode; else call comment-region"
  (interactive)
  ;; KLUDGE: should bind key in buffer, but I'm lazy
  (cond ((string-equal mode-name "nXML")
(save-excursion
  (narrow-to-region (point) (mark))
  (goto-point-min)
  (save-excursion (replace-string "--" "\\-\\-"))
  (insert "<!--\n")
  (goto-point-max)
  (insert "-->\n")
  (widen)))
(t (comment-region (point) (mark)))))

(defun my-nxml-uncomment-region ()
  "uncomment a block if in nXML mode; else call uncomment-region
assumes it was commented by my-nxml-comment-region"
  (interactive)
  ;; KLUDGE: should bind key in buffer, but I'm lazy
  (cond ((string-equal mode-name "nXML")
(save-excursion
  (search-backward "<!--\n")
  (delete-char 5)
  (let ((start (point)) end)
    (search-forward "-->\n")
    (delete-char -4)
    (setq end (point))
    (save-excursion (replace-string "\\-\\-" "--" nil start end)))))
(t (uncomment-region (point) (mark)))))

www.emacswiki.org/emacs/NxmlMode#toc13

– Tim Chambers 1E4AF729D5CEFFD0

Re: POC comment/uncomment region in nxml-mode

[Andreas Röhler]

On 23.07.2014 01:22, Tim Chambers wrote:
> Here's a POC for interactively commenting/uncommenting a region in
> nxml-mode. I guess if I wanted to submit this as an enhancement to
> nxml-mode I'd have to properly integrate the functions into nXML mode.
> Looking for motivation. Anyone interest in pursuing this?
>
> (defun my-nxml-comment-region ()
>    "comment a block if in nXML mode; else call comment-region"
>    (interactive)
>    ;; KLUDGE: should bind key in buffer, but I'm lazy
>    (cond ((string-equal mode-name "nXML")
> (save-excursion
>    (narrow-to-region (point) (mark))
>    (goto-point-min)
>    (save-excursion (replace-string "--" "\\-\\-"))
>    (insert "<!--\n")
>    (goto-point-max)
>    (insert "-->\n")
>    (widen)))
> (t (comment-region (point) (mark)))))
>
> (defun my-nxml-uncomment-region ()
>    "uncomment a block if in nXML mode; else call uncomment-region
> assumes it was commented by my-nxml-comment-region"
>    (interactive)
>    ;; KLUDGE: should bind key in buffer, but I'm lazy
>    (cond ((string-equal mode-name "nXML")
> (save-excursion
>    (search-backward "<!--\n")
>    (delete-char 5)
>    (let ((start (point)) end)
>      (search-forward "-->\n")
>      (delete-char -4)
>      (setq end (point))
>      (save-excursion (replace-string "\\-\\-" "--" nil start end)))))
> (t (uncomment-region (point) (mark)))))
>
> www.emacswiki.org/emacs/NxmlMode#toc13
>
> – Tim Chambers 1E4AF729D5CEFFD0
>
>

Why not just M-x comment-dwim?

Andreas

Re: POC comment/uncomment region in nxml-mode

[Stefan Monnier]

> Here's a POC for interactively commenting/uncommenting a region in
> nxml-mode. I guess if I wanted to submit this as an enhancement to
> nxml-mode I'd have to properly integrate the functions into nXML mode.
> Looking for motivation. Anyone interest in pursuing this?

IIUC, this is indeed needed, thank you.
A few comments, tho:
- It should not create new commands.  Instead it should set
  (un)comment-region-function buffer-locally.
- It should use the default (un)comment-region functions internally
  (e.g. first quote all "--", then call the default comment-region).
- I don't think you need to turn "--" into "\-\-".  Turning them into
  "-\-" should be sufficient.
- comment-region followed by an uncomment-region should also work on
  a region which already contains comments with a quoted "--"
  (i.e. with a "-\-").  For that I think you also need to quote "-\-" to
  "-\\-" and to unquote "-\\-" to "-\-" (and same for any number of
  backslashed between dashes).

Would you like to try to submit  revised patch?


        Stefan

Re: POC comment/uncomment region in nxml-mode

[Tim Chambers]

> IIUC, this is indeed needed, thank you.
> A few comments, tho:...

Thank you for the feedback, Stefan! Exactly what I was looking for. I hope
we can meet f2f someday so I can buy you a beverage of your choice. [1]

> Would you like to try to submit  revised patch?

Yes, I would like to submit a patch. I need to make time to study [2]
and [3] first. I also need to review [4]. So thank you for inspiring
me! If [2] and [3] need any touch-up, this week would be the time. I'm
going to get started this weekend.

> From: =?UTF-8?B?QW5kcmVhcyBSw7ZobGVy?= <andreas.roehler@online.de>
> Message-ID: <53CF57D3.1050605@online.de>
> Date: Wed, 23 Jul 2014 08:36:03 +0200

> Why not just M-x comment-dwim?

Andreas, Stefan acknowledged the problem I was trying to correct: '--'
in XML comments should be escaped. Does that make sense to you?

All, the other innovation I want to make is to comment regions in XML
with a single pair of <!-- --> instead of commenting every line. Can
anyone point me to the history of why line-by-line XML comments are
the norm in emacs, even though XML supports block comments?

Also, have any insights to share re. relationship between
un/comment-region and comment-dwim? These specifics are all new to me,
but I'm a quick study who is motivated to make emacs better.

– tbc

[1] details of this offer being the same as those specified at
www.emacswiki.org/emacs-en/tbc
[2] www.gnu.org/software/emacs/CONTRIBUTE
[3] www.gnu.org/software/emacs/manual/html_node/emacs/Sending-Patches.html
[4]
lists.gnu.org/archive/cgi-bin/namazu.cgi?query=nxml&submit=Search%21&idxname=bug-gnu-emacs

Re: POC comment/uncomment region in nxml-mode

[Stefan Monnier]

> All, the other innovation I want to make is to comment regions in XML
> with a single pair of <!-- --> instead of commenting every line.  Can
> anyone point me to the history of why line-by-line XML comments are
> the norm in Emacs, even though XML supports block comments?

That's just the default `comment-style', globally.
You probably want to configure it to something else globally as well
(assuming you don't like line-by-line commenting with /*...*/ in
C either, for example).

> Also, have any insights to share re. relationship between
> un/comment-region and comment-dwim? These specifics are all new to me,
> but I'm a quick study who is motivated to make emacs better.

comment-dwim is just a wrapper that calls different comment operations
(e.g. comment-region, comment-kill, ...) depending on "context".


        Stefan