Re: Add functions to C-mode?

[saneman <ddd@sdf.com>]

Alan Mackenzie wrote:
> Hi, Saneman!
> 
> On Sat, Apr 19, 2008 at 01:04:06PM +0200, saneman wrote:
>> I would like to add/change the comment/uncomment function in the C-mode 
>> for emacs.
> 
>> Currently it only works when a piece of text is selected and then /* */
>> is inserted.
> 
> OK, just to check, "it" here means "M-;" (or your newly bound C-d), bound
> to `comment-dwim', doesn't it?
> 
> I'm not sure about "selected" (I don't use delete-selection-mode and
> stuff like that), but the "/* */" style of comments is fixed for C.
> Somebody asked some while ago for a way to change this to "//", and I'm
> planning to add a command to CC Mode (probably C-c C-;) in the next
> release to toggle the commenting style.
> 
>> I would like to change the function to just insert // even though some 
>> text might not be selected.
> 
> In the meantime, you could use the following workaround.  M-; (or your
> C-d ;-) will then insert "// ".
> 
>     (defun sm-do-line-comments ()
>       (setq comment-start "// ")
>       (setq comment-end ""))
>     (add-hook 'c-mode-hook 'sm-do-line-comments)
> 


But I still have to select the lines that I want to comment out. If the 
cursor is on a line the I would like to comment out and I press C-d the 
// get inserted and the end of the line.

Only when I select the line and then press C-d it works.

Is there some way to insert // at the start of the line without first 
selecting it?