Why my book can be downloaded for free (2014)(blog.plover.com)

    use v5
    use Stream 'node';

    sub iterator_to_stream {
      my $it = shift;
      my $v = $it->();
      return unless defined $v;
      node($v, sub { iterator_to_stream($it) });
    }

    use v6;

    sub iterator-to-stream ( Iterator $it ) {
      Seq.new($it)
    }