19/12/07 00:44:47.39 7zlttp1T.net
>>101 Perl5
no warnings 'experimental::signatures';
use feature qw(say signatures);
sub Y($f) { sub {$f->(Y($f))->(@_)} } # Y combinator w/ recursive
$s = sub ($n) {$n and $n + $s->($n - 1)}; # calc series recursive
say Y(sub ($f) { $s })->(100);