#!/usr/bin/perl -w
use strict;

my $string = 'abcbar';
my $sub = get_backref( $string );

print $sub;

sub get_backref {
	my $string = shift;
	my $regex  = '(foo)|(bar)|(baz)';
	my $backref = 0;
	
	# This is the number of possible backreferences
	# It's easier to set than generate dynamically
	my $limit = 3;
	local ( $1, $2, $3 );

	$string =~ /$regex/;
	for ( 1 .. $limit ) {
		no strict 'refs';
		$backref = $_, last if defined $$_;
	}
	return $backref;
}