sub hanoi
{
    my $move_disk = pop(@_);

    local *_hanoi = sub {
        my ( $n, $start, $end, $extra ) = @_;

        if ( $n == 1 )
        {
            $move_disk->( 1, $start, $end );
        }
        else
        {
            _hanoi( $n - 1, $start, $extra, $end );
            $move_disk->( $n, $start, $end );
            _hanoi( $n - 1, $extra, $end, $start );
        }
    };

    &_hanoi;
}

hanoi( $disk, 'A', 'B', 'C', \&check_move );
hanoi( $disk, 'A', 'B', 'C', \&hprint );