[0][1][2][3][4]13
[5][6][7]57
3

##</code><code>##

use List qw/strict-lazy/;
# now all list processing is haskell-like strictly lazy
# this is mostly good for testing laziness ;)

use List qw/parallel/;
# allow parallel processing of lazy lists, even when 
# when it's not that lazy. This is the default.