Ignoring a key event completely

Ignoring a key event completely

[Michael Schutte]

Hi everybody,

The XKB layout I’m using [1] defines an additional modifier, the
Navigation key.  Whenever I press it, Emacs responds by beeping and
printing “<key-17> is undefined”.  I can suppress this by
global-set-keying it to 'ignore, but this does not turn it off
completely.  In particular:

 * Hitting the key still interrupts Isearch, which is very annoying.
 * M-Nav, C-Nav and C-M-Nav also need to be 'ignored, which does not
   seem very elegant to me.
 * Messages appearing in the echo area are nuked when I press Nav (this
   is minor, of course, but you get the idea).

So, I’m looking for a way to make Emacs completely forget about the key,
to make it as no-oppy as Shift, Ctrl, etc., but I simply can’t find out
how to do this on my own.  Could anyone give me a clue?

[1] <https://neo.eigenheimstrasse.de/svn/linux/X/de>; grep for Mod4

Thanks in advance,
-- 
Michael Schutte <m.schutte.jr@gmail.com>

Re: Ignoring a key event completely

[Kevin Rodgers]

Michael Schutte wrote:
> Hi everybody,
> 
> The XKB layout I’m using [1] defines an additional modifier, the
> Navigation key.  Whenever I press it, Emacs responds by beeping and
> printing “<key-17> is undefined”.  I can suppress this by
> global-set-keying it to 'ignore, but this does not turn it off
> completely.  In particular:
> 
>  * Hitting the key still interrupts Isearch, which is very annoying.
>  * M-Nav, C-Nav and C-M-Nav also need to be 'ignored, which does not
>    seem very elegant to me.
>  * Messages appearing in the echo area are nuked when I press Nav (this
>    is minor, of course, but you get the idea).
> 
> So, I’m looking for a way to make Emacs completely forget about the key,
> to make it as no-oppy as Shift, Ctrl, etc., but I simply can’t find out
> how to do this on my own.  Could anyone give me a clue?
> 
> [1] <https://neo.eigenheimstrasse.de/svn/linux/X/de>; grep for Mod4

I don't think I've ever been on a system that generates events like
<key-17>.  What does Emacs display after typing `a', then the Navigation
key, then `C-h l'?

In any case, it looks like the Navigation key is not a modifier key like
Shift, Control, etc.  So perhaps something like this will work:

(define-key special-event-map (kbd "<key-17>") 'ignore)

See the "Controlling Active Maps" and the "Special Events" nodes of the
Emacs Lisp manual.

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: Ignoring a key event completely

[Michael Schutte]

On Mon, May 12, 2008 at 08:53:39PM -0600, Kevin Rodgers wrote:
> I don't think I've ever been on a system that generates events like
> <key-17>.  What does Emacs display after typing `a', then the Navigation
> key, then `C-h l'?

Just the thing one would expect: a <key-17> C-h l.

> In any case, it looks like the Navigation key is not a modifier key like
> Shift, Control, etc.  So perhaps something like this will work:
>
> (define-key special-event-map (kbd "<key-17>") 'ignore)
>
> See the "Controlling Active Maps" and the "Special Events" nodes of the
> Emacs Lisp manual.

Yup, that’s exactly what I was looking for, thanks a lot!  It still
needs the same treatment for M-, C- and S-, but I can live with that.

Cheers,
-- 
Michael Schutte <m.schutte.jr@gmail.com>

Re: Ignoring a key event completely

[Kevin Rodgers]

Michael Schutte wrote:
> On Mon, May 12, 2008 at 08:53:39PM -0600, Kevin Rodgers wrote:
>> I don't think I've ever been on a system that generates events like
>> <key-17>.  What does Emacs display after typing `a', then the Navigation
>> key, then `C-h l'?
> 
> Just the thing one would expect: a <key-17> C-h l.

Does `C-h v function-key-map' show a key sequence that is mapped to
[key-17]?

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: Ignoring a key event completely

[Michael Schutte]

On Tue, May 13, 2008 at 06:54:09AM -0600, Kevin Rodgers wrote:
> Does `C-h v function-key-map' show a key sequence that is mapped to
> [key-17]?

No, it doesn’t.  I also tried (define-key function-key-map [key-17] [])
now, but it seems to behave exactly the same way as doing it in
special-event-map (i.e. I have to see about C-, M-, etc. myself).  Is
there some more magic I’m missing?

-- 
Michael Schutte <m.schutte.jr@gmail.com>