Re: UTF-8 in copyright files?

[Thomas Wouters <thomas@xs4all.net>]

On Thu, Dec 18, 2003 at 01:38:35PM +0000, Colin Watson wrote:
> On Thu, Dec 18, 2003 at 10:12:13AM +0100, Sven Luther wrote:
> > Other problems is sshing from a non UTF terminal, but then luit helps,
> > but there is not really much we can do there, no ?

> This is a pain in the arse, frankly, because there's no way I've found
> to pass environment variables such as LANG across the ssh connection. If
> anyone knows of a not-too-hacky way to do this, I'd be interested.

A colleague of mine wrote the attached Perl script to detect UTF-8 (the only
real language setting he, and I, want to transparently inherit over SSH (and
other) connections is LC_CTYPE, anyway.) Place it somewhere, and call it
from your .bashrc with something like:

if [ -n "$PS1" ]; then
    eval `detect-utf8-term`
fi

You'll have to fiddle the script itself to use it with tcsh, but not in any
spectacular way. It needs Term::ReadKey (libterm-readkey-perl). It only sets
LC_CTYPE, and it sets it hardcoded to en_US.UTF-8 when it detects UTF-8.
It also eats all typeahead, unfortunately, which may be annoying depending
on your habits.

-- 
Thomas Wouters <thomas@xs4all.net>

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#!/usr/bin/perl -w
# Written by Jan-Pieter Cornet <johnpc@xs4all.nl>,
# released to the public domain. If you break it, you get to keep both pieces.

use strict;
use Term::ReadKey;
use bytes;

my $lc_ctype = $ENV{LC_CTYPE} || $ENV{LC_ALL} || $ENV{LANG};
if ( defined($lc_ctype) && $lc_ctype =~ /utf-?8/i ) {
    ### uncomment me if you want silly messages in normal xterms
    #print STDERR "Already UTF-8 enabled\n";
    exit;
}

ReadMode 'cbreak';

### Send CR, test sequence that's valid ISO8859-1 and valid UTF8, and
### cursor reporting escape ^[[6n.
print STDERR "\r", chr 0xC2, chr 0xA4, chr 27, '[6n';

### read response from terminal, usually ^[[#;#R
my $r = '';
while ( my $c = ReadKey 0.1 ) {
    $r .= $c;
    last if $c eq 'R';
}

ReadMode 'restore';

### parse returned string
my($x) = $r =~ /^\x1B\[\d+;(\d+)R$/;
if ( !defined $x ) {
    print STDERR "Couldn't parse return: ",
        ( map { sprintf "%02x ", ord } split //, $r ), "\n";
}
elsif ( $x == 2 ) {
    ### It's UTF-8 enabled, search for a valid locale
    my @locales = `locale -a`;
    my($utflocale) = grep /utf-?8/i, @locales;
    ### sensible default...?
    $utflocale ||= 'en_US.UTF-8';
    print STDERR "\r \r";
    print "export LC_CTYPE=$utflocale\n";
}
elsif ( $x == 3 ) {
    ### it's standard ISO8859
    print STDERR "\r  \r";
}
else {
    ### dunno?
    print STDERR "Strange x-coord after test: $x\n";
}