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