Re: xterm [menu] key definition

[Ergus]

On Tue, Aug 24, 2021 at 01:00:14PM +0200, tomas@tuxteam.de wrote:
> On Tue, Aug 24, 2021 at 11:17:41AM +0200, Ergus wrote:
>
> [...]
>
> > Then if you have it, could you tell what escape sequence it sends throw
> > Xterm by default? If you could do the same with urxvt will be very nice
> > ;)
>
> Sure :)
>
> I tried both. My methodology is to run 'cat | hexdump -C' in each of
> xterm and urxvt and to terminate input with CTRL-D.
>
> I tested the methodology itself by trying some keys where I more or
> less knew what to expect ("a", <ENTER>, but also <F2>).
>
> The result is... nothing.
>
> This may sound disappointing, but then, xterm tries to pretend being
> a VT220, and those had no "print" key.
>
> OTOH, it would be subestimating the folks at MIT Project Athena to
> assume that would not be configurable. Hard-coding this wouldn't
> have made sense to them.
>
> So yes, for xterm at least (but I think for urxvt, too), you can
> configure that with X Resources. This one [1] looks as if there
> were hope as long as there is a keysym. No time to try it out
> at the moment, though.
>
> Whether the application (Emacs) running "in" the xterm can change
> that dynamically (or has to tell the user to do that for it ;)
> is the next interesting question :-)
>
> Cheers
> [1] http://www.fifi.org/doc/xterm/xterm.faq.html#how2_fkeys
>   which is, BTW, a wonderful resource in things xterm.
> - t


Hi!

Thanks for the link! Of course we can emulate anything in xterm. The
question is what xterm does by default? and why we bound the menu
sequence to [print] instead of [menu] if emacs internally uses [menu]
for execute-extended-command?

If xterm assumes it is a VT220; then we must assume the same when using
it by default (until we implement a more complex API to ask
xterm... (but that may be inefficient and probably don't worth it for
such a detail).

Sometimes emacs assumes there is a [menu] key but then in xterm the same
key is interpreted as [print] by emacs. So a very comfortable key (for
those who have it) that we can't use consistently.

Part of my intention is to minimize the "special" customization required
when using xterm+emacs (either in Xdefaults or in init.el); any fancy
more specific customization can be made latter by the user when he gets
familiar with the rest of the environment (GNU/Linux, xterm, emacs,
Elisp, the command line interface, the OS configuration system...) for
new users it is like getting into Narnia the fist week/month.

I expect that most of the emacs features work and behave as similar as
possible when using the xterm, tty or gui without customization,
everything out of the box.