terminfo

[Ian Lepore]

On Fri, 2014-02-21 at 13:05 +0100, Ed Schouten wrote:
> Hi Bryan,
> 
> On 19 February 2014 13:17, Bryan Drewery <bdrewery at freebsd.org> wrote:
> > Why do we not use terminfo? Our termcap is quite aged and missing a lot
> > of modern terminals/clients.
> 
> It is true that our termcap is quite aged, but the fact is, once you
> add entries for a certain terminal, there's little need to update it
> after that. ncurses itself is not really a moving target. What kind of
> modern terminals/clients are missing?
> 
> > Using terminfo would allow us to use the already well maintained database from ncurses. Is it just a matter of someone doing the work or are there other reasons?
> 
> It's just a matter of someone doing the work. It would be nice if we
> ever made this change.
> 
> On the other hand, I might have a radical point of view here: maybe we
> could consider taking the approach of sticking to termcap and
> installing /etc/termcap.small as the system's default termcap. Or
> maybe patch up our termcap routines to just hardcode the sequences.
> 
> I won't deny that termcap was really useful at one point in time, but
> let's be honest: the variety of terminals out there has massively
> dropped over time. Terminal emulation has become a solved problem. As
> of FreeBSD 9, syscons supports all the sequences described in
> xterm-256color, though it isn't able to print more than 8 colours,
> which is why we use TERM=xterm. Tools like screen, tmux, etc., they
> use a different TERM type, but this is mainly used to detect whether
> the process is running inside of screen or tmux. It does not strongly
> affect the kinds of sequences that are being emitted. They work
> perfectly fine if you just set TERM to xterm or xterm-256color.
> 
> I suspect the following logic would be sufficient for at least 99.5%
> of our users:
> 
> if $TERM contains 256
>   use xterm-256color
> else
>   use xterm
> 
> It's a shame I am so short on time nowadays, but I think it would make
> so much sense to just come up with some kind of document that
> standardizes the intersection of the features supported by most common
> terminal emulators and get it rubber stamped by the maintainers of
> various terminal emulators. If it turns out some kind of terminal
> emulator does something in a non-standard way, we can just slap this
> document in the author's face. That would not only benefit FreeBSD,
> but also most of the other flavours of UNIX.
> 
> $TERM should die.
> 

All of that seems to assume that every terminal actually being used in
the world today is either xterm or something that emulates it.  Try
using vi on a serial console on an embedded ARM board and you'll get a
quick frustrating lesson in how not-xterm a serial console is.  I've yet
to find a combo of serial comms program and TERM setting that actually
works well and lets you edit a file with vi.

-- Ian