#!/usr/bin/perl
use strict;
use warnings;
use utf8;
use Unicode::Normalize;
use charnames ':full';
use String::Multibyte;
my $str = NFKD "ÄO";
sub mydump {
	print map { '\N['. charnames::viacode(ord $_) . ']' } 
			split m//, $_[0];
	print "\n";
}

my $u = String::Multibyte->new('Grapheme');

mydump $str;
mydump $u->strrev($str);
binmode STDOUT, ':utf8';
print $u->strrev($str), "\n";
__END__
\N[LATIN CAPITAL LETTER A]\N[COMBINING DIAERESIS]\N[LATIN CAPITAL LETTER O]
\N[LATIN CAPITAL LETTER O]\N[LATIN CAPITAL LETTER A]\N[COMBINING DIAERESIS]
OÄ