-my @chars = ((map {chr} ord '!' .. ord 'Z'), 'a'..'z');
-splice @chars, $_, 1, () for 2, 3-1, 5-2, 31-3; # remove character exceptions # $ & @
-my @chars2 = (@chars, '_'); # trailing character (extended set)
+my @chars = (
+ [qw{! " % ' ( ) * + , - . /}],
+ ['0'..'9'], [qw{: ; < = > ?}],
+ ['A'..'M'], ['N'..'Z'],
+ ['a'..'m'], ['n'..'z'],
+);
+my @chars2 = (['_'], @chars); # trailing character (extended set)
+my @columns = !exists $get{split} ? \@chars2 :
+ ([@chars2[0, 1, 3, 4, 6]], [@chars2[2, 5, 7]]);
+
+if ($mode) {
+ my $xorg = do 'data/digraphs-xorg.inc.pl'
+ or die "Error loading Xorg data: ", $@ // $!;
+ $_ = [ord $_] for values %{$xorg};
+ $xorg->{$_}->[2] = # class = compatibility
+ $di->{$_} ? $di->{$_}->[0] != $xorg->{$_}->[0] ? 'l1' : # conflict
+ $di->{$_}->[2] =~ /\bu-di\b/ ? 'l5' : 'l3' : 'l2' # rfc|any|none
+ for keys %{$xorg};
+
+ for my $cp (map {$_->[0]} values %{$xorg}) {
+ next if (state $seen = {})->{$cp}++; # List::MoreUtils::uniq
+
+ # find multiple equivalent mnemonics
+ my @equiv = grep {$cp eq $_->[0]}
+ map {$xorg->{$_}} sort keys %{$xorg}; # values ordered by mnem.
+
+ # search for the most compatible match
+ my ($compat) = sort {
+ $equiv[$b]->[2] cmp $equiv[$a]->[2] # highest level
+ || $b <=> $a # fallback to last mnemonic
+ } 0 .. $#equiv;
+
+ # reclassify all but one as level 0 (omitted)
+ splice @equiv, $compat // -1, 1, ();
+ $_->[2] = 'l0 ex' for @equiv;
+ }
+
+ $chars2[0] = [qw( # ^ _ ` ~ )];
+ @chars = @chars2;
+ $di = $xorg;
+}