Select Code to Download

#! /usr/bin/perl

...
while (my $x = $it->()) {
    dd $x;
}

sub choose {
    my ($n, $k) = @_;
    !$n ? (["$n-$k"]) x !$k
        : map [@$_, "$n-$k"], choose($n-1, $k), choose($n-1, $k-1)
}