package List::Navigator;

sub new
{
	my $class = shift;
	my ($list) = @_;

	my $data = {};
	my ($previous, $next);
	for my $item (@$list)
	{
		$data->{$item}{PREVIOUS} = $previous;
		$data->{$previous}{NEXT} = $item if defined $previous;
		$previous = $item;
	}
	bless $data, $class;
}