#!/usr/bin/perl --

use strict;
use warnings;

for my $regex (  qr/hello/i, qr/hello/ ){
   my( $left, $right ) = $regex =~ /\(\?([^-:]*)-([^-:]*):/;
   print "$regex ";
   print "is_ci" if $left =~ /i/i;
   print "\n";
}
__END__

(?i-xsm:hello) is_ci
(?-xism:hello)
[download]

See also YAPE::Regex