$Ideographic = '(?:\xE3\x80[\x87\xA1-\xA9]|\xE4(?:[\xB8-\xBF][\x80-\xBF])|\xE5(?:[\x80-\xBF][\x80-\xBF])|\xE6(?:[\x80-\xBF][\x80-\xBF])|\xE7(?:[\x80-\xBF][\x80-\xBF])|\xE8(?:[\x80-\xBF][\x80-\xBF])|\xE9(?:[\x80-\xBD][\x80-\xBF]|\xBE[\x80-\xA5]))';

##</code><code>##

use strict;
use warnings;
use utf8;  # comment this line out and it matches
use XML::RegExp;

my $name= 'timestamp';  # contains plain ASCII letters only!
my $result= $name =~ /^$XML::RegExp::Name$/o;
print "result is $result\n";