#!/usr/bin/perl

my $html = qq(  abcdef  );
sub check
{
        my $pattern = shift;

        my @br;

        eval "\@br = '  abcdef  ' =~ m/$pattern/x";

        die "$@\n" if $@;
        print "PATTERN=m/$pattern/x\n";
        print "ANSWER = ";
        print join("-",@br),"\n";
}

check('(?-x:(abcdef))');
check('(?-x:(abcdef)) # comment here');