Re: UTF-8 and Alt key in the console

From: H. Peter Anvin
Date: Fri Mar 28 2008 - 19:27:23 EST


Jan Engelhardt wrote:
The best probably would be to introduce an escape code, along the lines
of other escape codes in the terminal interfae.

You're right.

Many say Unix is also broken compared to Plan 9.. sometimes it's
too late. The real fix for this issue seems like it'd be very
hard to accomplish.

The idea of revamping the escape codes is not all that bad.

Thanks to terminfo, this should be easy. Change vt.c,
add corresponding terminfo entry and set TERM to something
that has not previously existed.

About the ESC key, I thought, would it suffice to replace its
current output of ^[ with ^[^[?

It would be better to assign a CSI (ESC [) code to it, like other function keys. Unfortunately, the terminal everyone tries to emulate (Linux does so quite poorly due to its broken implementation of ISO 2022, but that's less of an issue with UTF-8), VT 220, had ESC on the F11 key, so the CSI 2 3 ~ sequence it uses we use for the F11 key. Doesn't mean we can't assign another one.

One would also like to distinguish, say, Backspace from Ctrl-H. This is trickier, because the termios settings don't permit compound keys. The most obvious way to deal with that is an escape code for Ctrl-H, but that has the risk of breaking a lot of other things.

-hpa
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