#!/usr/bin/env perl
use 5.014;
use warnings;
use utf8;
use open IO => ':utf8', ':std';
use Data::Dump 'pp';

our $VERSION = '1.00';

open my $keysymh, '<', '/usr/include/X11/keysymdef.h'
	or die "Could not find keysym definitions: $!\n";

my %keysym;
while (readline $keysymh) {
	m{
		\A  [#]define[ ]XK_ (?<name>[a-zA-Z_0-9]+)
		\h+ 0x(?<value>[0-9a-f]+)
		\h* [/][*] [\h(] U[+] (?<unicode>[0-9A-F]{4,6})
	}msx or next;
	$keysym{ $+{name} } = chr hex $+{unicode};
}

say "# automatically generated by $0";
say '+{';

while ($_ = readline) {
	my ($mnem, $chr, $trail) = /^<Multi_key>\h(.*?)\h+:\h"([^"]+)"\h*(.*)/
		or next;
	$chr =~ s/\\(.)/$1/g;
	$mnem !~ /<dead|<KP_|<U[0-9A-Fa-f]{4}/ or next;  # skip non-standard keys
	$mnem =~ s{<([^>]+)> ?}{$keysym{$1} // die "reference to unknown keysym $1\n"}eg;
	$mnem !~ /[^ -\x7F]/ or next;  # skip unicode
#	(state $seen = {})->{$chr}++ and next;
	printf "%s => %s,\n", pp($mnem), pp($chr);
}

say '}';

__END__

=head1 NAME

mkdigraphs-xorg - Output Xorg compose sequences

=head1 SYNOPSIS


    mkdigraphs-xorg /usr/share/X11/locale/en_US.UTF-8/Compose >digraphs-xorg.inc.pl
    perl -e'$di = do "digraphs-xorg.inc.pl"; print chr $di->{AT}'

=head1 DESCRIPTION

Extracts Multi_key definitions from X11/Xorg Compose.pre include file.
If successful, Perl code is output resulting in a hash
with Unicode code points keyed by mnemonics.
Any errors and warnings are given at STDERR.

=head1 AUTHOR

Mischa POSLAWSKY <perl@shiar.org>

=head1 LICENSE

Licensed under the GNU Affero General Public License version 3.