How to use c-style to comment a region?

How to use c-style to comment a region?

[William Xue]

Hi,

In cpp files, in following code, for e.g.:

ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * 1000 * 5);

I wanted to modify the second 1000 to 2000 for testing, but wanted to keep  
the orignal value for restoring it later.

after selected 1000 and pressed C-c C-c :

                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * // 1000
                                          * 5); // 1 second

Can it be:

                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * /* 1000  
*/  * 5); // 1 second

Maybe there are some settings for it, but I havn't found them.

I know that add /* -*- C -*- */ at the beginning of the file can affect  
the comment style for the whole file.
That's not my request, I only want a command or a keybinding.


Thanks!

-- 
Sincerely yours,
William

Re: How to use c-style to comment a region?

[martin rudalics]

[-- Attachment #1: Type: text/plain, Size: 473 bytes --]

 > That's not my request, I only want a command or a keybinding.

You could try to bind

(defun my-cpp-comment-region (beg end &optional arg)
   (interactive "*r\nP")
   (let ((comment-start "/* ")
	(comment-end " */"))
     (comment-region beg end arg)))

to a key.

BTW with comment-styles box / box-multi and newline terminated comment
syntax `comment-region' comments out the entire text from the beginning
of the region till EOL.  The attached patch should cure that.

[-- Attachment #2: new-comment.patch --]
[-- Type: text/plain, Size: 3162 bytes --]

*** newcomment.el.~1.101.~	Mon Apr  2 07:45:08 2007
--- newcomment.el	Thu May 10 10:38:22 2007
***************
*** 926,941 ****
  the region rather than at left margin."
    ;;(assert (< beg end))
    (let ((no-empty (not (or (eq comment-empty-lines t)
! 			   (and comment-empty-lines (zerop (length ce)))))))
      ;; Sanitize CE and CCE.
      (if (and (stringp ce) (string= "" ce)) (setq ce nil))
      (if (and (stringp cce) (string= "" cce)) (setq cce nil))
      ;; If CE is empty, multiline cannot be used.
      (unless ce (setq ccs nil cce nil))
      ;; Should we mark empty lines as well ?
      (if (or ccs block lines) (setq no-empty nil))
      ;; Make sure we have end-markers for BLOCK mode.
!     (when block (unless ce (setq ce (comment-string-reverse cs))))
      ;; If BLOCK is not requested, we don't need CCE.
      (unless block (setq cce nil))
      ;; Continuation defaults to the same as CS and CE.
--- 926,943 ----
  the region rather than at left margin."
    ;;(assert (< beg end))
    (let ((no-empty (not (or (eq comment-empty-lines t)
! 			   (and comment-empty-lines (zerop (length ce))))))
! 	ce-sanitized)
      ;; Sanitize CE and CCE.
      (if (and (stringp ce) (string= "" ce)) (setq ce nil))
+     (setq ce-sanitized ce)
      (if (and (stringp cce) (string= "" cce)) (setq cce nil))
      ;; If CE is empty, multiline cannot be used.
      (unless ce (setq ccs nil cce nil))
      ;; Should we mark empty lines as well ?
      (if (or ccs block lines) (setq no-empty nil))
      ;; Make sure we have end-markers for BLOCK mode.
!     (when (and block (not ce)) (setq ce (comment-string-reverse cs)))
      ;; If BLOCK is not requested, we don't need CCE.
      (unless block (setq cce nil))
      ;; Continuation defaults to the same as CS and CE.
***************
*** 945,951 ****
        (goto-char end)
        ;; If the end is not at the end of a line and the comment-end
        ;; is implicit (i.e. a newline), explicitly insert a newline.
!       (unless (or ce (eolp)) (insert "\n") (indent-according-to-mode))
        (comment-with-narrowing beg end
  	(let ((min-indent (point-max))
  	      (max-indent 0))
--- 947,954 ----
        (goto-char end)
        ;; If the end is not at the end of a line and the comment-end
        ;; is implicit (i.e. a newline), explicitly insert a newline.
!       (unless (or ce-sanitized (eolp))
! 	(insert "\n") (indent-according-to-mode))
        (comment-with-narrowing beg end
  	(let ((min-indent (point-max))
  	      (max-indent 0))
***************
*** 1163,1169 ****
                               (buffer-substring (point)
                                                 (progn (move-to-left-margin)
                                                        (point)))))))))))))
!                     

  ;;;###autoload
  (defun comment-indent-new-line (&optional soft)
--- 1166,1172 ----
                               (buffer-substring (point)
                                                 (progn (move-to-left-margin)
                                                        (point)))))))))))))
! 

  ;;;###autoload
  (defun comment-indent-new-line (&optional soft)

[-- Attachment #3: Type: text/plain, Size: 142 bytes --]

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Re: How to use c-style to comment a region?

[Stefan Monnier]

> BTW with comment-styles box / box-multi and newline terminated comment
> syntax `comment-region' comments out the entire text from the beginning
> of the region till EOL.  The attached patch should cure that.

I'm not sure I understand the problem (and hence the solution).  Can you
show me a recipe to reproduce this problem?


        Stefan

Re: How to use c-style to comment a region?

[martin rudalics]

 > I'm not sure I understand the problem (and hence the solution).  Can you
 > show me a recipe to reproduce this problem?

Sorry for being cryptic.  With emacs -Q customize `comment-style' to box
or box-multi.  In *scratch* insert

(foo bar baz)

set the region around bar and do `comment-region'.  Gets you

(foo ;; bar ;; baz)

instead of

(foo ;; bar ;;
      baz)

Responsible is the

     (when block (unless ce (setq ce (comment-string-reverse cs))))

line in `comment-region-internal' which makes the subsequent

       (unless (or ce (eolp)) (insert "\n") (indent-according-to-mode))

fail.  Obviously it fails in the cpp example of the OP as well.

Re: How to use c-style to comment a region?

[William Xue]

On Thu, 10 May 2007 16:50:20 +0800, martin rudalics <rudalics@gmx.at>  
wrote:

>  > That's not my request, I only want a command or a keybinding.
>
> You could try to bind
>
> (defun my-cpp-comment-region (beg end &optional arg)
>    (interactive "*r\nP")
>    (let ((comment-start "/* ")
> 	(comment-end " */"))
>      (comment-region beg end arg)))
>
> to a key.

I bind it to C-; and it works very well.

Thank you very much!

>
> BTW with comment-styles box / box-multi and newline terminated comment
> syntax `comment-region' comments out the entire text from the beginning
> of the region till EOL.  The attached patch should cure that.



-- 
Sincerely yours,
William

Re: How to use c-style to comment a region?

[Alan Mackenzie]

Hi, William!

On Thu, May 10, 2007 at 09:46:34AM +0800, William Xue wrote:
> Hi,

> In cpp files, in following code, for e.g.:

> ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * 1000 * 5);

> I wanted to modify the second 1000 to 2000 for testing, but wanted to
> keep  the orignal value for restoring it later.

> after selected 1000 and pressed C-c C-c :

>                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * // 1000
>                                          * 5); // 1 second

> Can it be:

>                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * /* 1000  
> */  * 5); // 1 second

> Maybe there are some settings for it, but I havn't found them.

No, there aren't any such settings.

> I know that add /* -*- C -*- */ at the beginning of the file can affect  
> the comment style for the whole file.
> That's not my request, I only want a command or a keybinding.

No, you certainly wouldn't want to have to use C mode just to get the
right sort of comments.

Some while ago, a CC Mode user requested a feature to toggle the type of
comment that M-; inserts within C Mode (i.e. /* ... */  <->  // ... \n).
I intend to write a new command to do just this, probably binding it to
C-c C-;.  This will hopefully get implemented in CC Mode 5.32, which I am
hoping to release shortly after both Emacs 22.1 and GPLv3 are done.

> Thanks!

> Sincerely yours,
> William

-- 
Alan Mackenzie (Ittersbach, Germany).

Re: How to use c-style to comment a region?

[William Xue]

On Fri, 11 May 2007 05:14:02 +0800, Alan Mackenzie <acm@muc.de> wrote:

> Hi, William!
>
> On Thu, May 10, 2007 at 09:46:34AM +0800, William Xue wrote:
>> Hi,
>
>> In cpp files, in following code, for e.g.:
>
>> ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * 1000 * 5);
>
>> I wanted to modify the second 1000 to 2000 for testing, but wanted to
>> keep  the orignal value for restoring it later.
>
>> after selected 1000 and pressed C-c C-c :
>
>>                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * // 1000
>>                                          * 5); // 1 second
>
>> Can it be:
>
>>                 ln_time_out.QuadPart = -((LONGLONG) 10 * 1000 * /* 1000
>> */  * 5); // 1 second
>
>> Maybe there are some settings for it, but I havn't found them.
>
> No, there aren't any such settings.
>
>> I know that add /* -*- C -*- */ at the beginning of the file can affect
>> the comment style for the whole file.
>> That's not my request, I only want a command or a keybinding.
>
> No, you certainly wouldn't want to have to use C mode just to get the
> right sort of comments.
>
> Some while ago, a CC Mode user requested a feature to toggle the type of
> comment that M-; inserts within C Mode (i.e. /* ... */  <->  // ... \n).
> I intend to write a new command to do just this, probably binding it to
> C-c C-;.  This will hopefully get implemented in CC Mode 5.32, which I am
> hoping to release shortly after both Emacs 22.1 and GPLv3 are done.

That's a good news for us. We'll wait for it!

Thanks!
:)

>
>> Thanks!
>
>> Sincerely yours,
>> William
>



-- 
Sincerely yours,
William