19/12/07 00:25:52.72 7zlttp1T.net
>>101 Perl5
no warnings 'experimental::signatures';
use feature qw(say signatures);
sub f($n) {$n and $n + f($n - 1)};
say f(100);
sub Y($f) { sub {$f->(Y($f))->(@_)} }
say Y(sub($f) { sub($n) { $n and $n + $f->($n - 1) } })->(100);