[Perl 6] Prime numbers in iterators

sub prime {
    my $n = 1;

    gather {
        loop {
            $n++;
            my $is-prime = True;

            loop (my $i = 2; $i <= $n.sqrt; $i++) {
                if $n mod $i == 0 {
                    $is-prime = False;
                    last;
                }
            }

            if $is-prime {
                take $n;
            }
        }
    }
}

# (2 3 5 7 11 13 17 19 23 29 31)
prime[10] == 31 or die "Wrong value";