2 of the 4 calls to hanoi only pass 4 arguments when it expects 5.

Update: Specifically, 

        hanoi( $n - 1, $start, $extra, $end );
        $move_disk->( $n, $start, $end );
        hanoi( $n - 1, $extra, $end, $start );

[download]
should be 
        hanoi( $n - 1, $start, $extra, $end, $move_disk );
        $move_disk->( $n, $start, $end );
        hanoi( $n - 1, $extra, $end, $start, $move_disk );

[download]

Update: Better fix: (Avoids having a million needless copies of $move_disk) 

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 );

[download]

In reply to Re: passing subroutine references by ikegami
in thread passing subroutine references by joe76

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