Re: Add functions to C-mode?

[Richard G Riley]

Alan Mackenzie <acm@muc.de> writes:

> Evening, Richard!
>
> On Mon, Apr 21, 2008 at 01:49:57PM +0200, Richard G Riley wrote:
>
>> Alan Mackenzie <acm@muc.de> writes:
>
>> > Morning, Saneman
>
>> > On Mon, Apr 21, 2008 at 09:36:55AM +0200, saneman wrote:
>> >> Alan Mackenzie wrote:
>
>> >> >>Currently it only works when a piece of text is selected and then
>> >> >>/* */ is inserted.
>
>> > [ .... ]
>
>> >> 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?
>
>> > I'm not quite sure exactly what you mean, but I don't think so (other
>> > than typing the two "/"s yourself, but that's boring).
>
>> > What exactly do you mean by "selecting" and why do you want to avoid
>> > this?
>
>> I would assume he means selecting the text. As one does for cut and
>> paste. Standard region manipulation.
>
> No.  "Selection" means chosing something from a range of alternatives.
> What is often called "selection" in editors other than emacs is actually
> nothing of the kind.  It's usually something more like "highlighting" or
> "marking".

I think my point was that in the context "selection" was fairly
obvious. Possibly I am wrong.

>
> The point of my question was to find out why Saneman objects to this
> "selecting", so as to be able to suggest something better.
>
>> > Somehow or other, you've got to indicate to Emacs _which_ lines(s)
>> > you want commented out (even if it's only one line).
>
>> > "Selecting" isn't really Emacs jargon.  When you drag the mouse over
>> > a buffer, the "mark" is left where you started, and point is put
>> > where you finish.  The "region" is the bit between point and mark,
>> > and many commands operate on the region.  There are lots of ways of
>> > setting the mark, too.  C-<space> is the most basic.
>
>> I think it would be fair to say that "selecting the text" is perfectly
>> clear in this instance.
>
> Except that it's not Emacs terminology.  Also, although it's a nice

Possibly not. But people who come to a help group are often not fluent
in "emacs" or "whatever" speak. I was merely pointing out that in the
context it seemed (to me) fairly clear what he meant.

> difference, the region in Emacs is a portion of the buffer, not merely
> the text within it; it's the blackboard as well as the chalk.  So talking
> about selecting "the text" can be confusing.

Yes - I can kind of accept that if one were to over think it.

>
>> > So, if you want to comment out lines (like all good programming
>> > standards forbid, yet everybody does ;-), make the region the
>> > pertinent lines.  Then do C-c C-c (`comment-region').  If you later
>> > want to undo this, put the region round these lines again, then do
>> > C-u C-c C-c.
>
>> In my set up the command is comment-dwim accessed from "M-;". I guess
>> this is part of emacs-22?
>
> No, that's a different command.  M-; (usually) adds a comment at the end
> of the current line, C-c C-c comments out the code in the region.

Not on my set up. It "does what I want" .. but that could be because of
changes I have long forgotten - a common issue with rusty .emacs  :-;

In other words, if I select some text ( to be devils advocate with the
terminology in this instance) it comments out the selected region ..