xterm+luit, vt100 line drawing problem

[Thomas Dickey]

On Sat, 6 Aug 2011, Alexey Dokuchaev wrote:

> hello here,
>
> i'm asking here since I failed to google the answer myself, and reading
> luit source code would probably eat too much of my time prior getting
> some knowledge about how this thing works :)
>
> my desktop is utf-8, but i need to access couple of old systems which
> use 8-bit locales (koi8-r, to be precise, but it does not matter).  it
> seems that luit is the way to go, when i ssh to remote host like this:
>
> 	LC_ALL=ru_RU.KOI8-R luit ssh ..., or
> 	luit -encoding koi8-r ssh ...
>
> i can see and input russian characters correctly.  however, midnight
> commander and ncurses-based programs display infamous "lqqqq" strings
> instead of lines/borders.  it seems that these lines are being drawn
> with ESC(0/(B sequences, which xterm (even in utf-8 locale) understands
> and renders correctly, but when passed through luit, those escape codes
> are stripped, so only letters remain.

luit (and screen) place additional restrictions on ESC(0, etc.,
because they use some of those combinations for their own purposes.

> i've attached a simple test program (might need some minor tweaking
> depending on your shell) to demonstrate the behavior, in utf-8 xterm, do:
>
> $ sh line.sh
> +-+-+
> +-+-+					(but in a nicer way, of course)
> +-+-+
> $ luit -encoding koi8-r sh line.sh
> lqwqk
> tqnqu					WTF??
> mqvqj
>
> (same thing happens over ssh, of course).  is there a way to have both
> utf-8, koi8-r (via luit), and vt100 lines in both xterm and luited
> shell/ssh?

As I recall it, it's technically possible (for the usual case) but
only by some hard work on luit.  The original author wasn't inclined,
and it's been an interesting-possibility-but-no-time issue for me.

-- 
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net