use strict;
my $str = '';
my $regex = qr/(?<LanguageTag>(?<langtag>(?<language>(?:[a-z]{2,3}(?<extlang>(?:\-[a-z]{3}){0,3}))|[a-z]{4}|(?<subtag>[a-z]{5,8}))(?:\-(?<script>[a-z]{4}))?(?:\-(?<region>[a-z]{2}|[0-9]{3}))?(?:\-(?<variant>[0-9a-z]{5,8}|[0-9][0-9a-z]{3}))*(?:\-(?<extension>(?<singleton>[a-wy-z0-9])(?:\-[0-9a-z]{2,8})+))*)|(?<privateuse>[xX](?:\-[0-9a-z]{1,8})+)|(?<grandfathered>[a-z]{1,3}(?:\-[0-9a-z]{2,8}){1,2}))/mip;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html