coro_generator.pl

use strict;
use warnings;
use Coro::Generator;
use Perl6::Say;

sub count {
    my $start = shift;
    generator {
        my $n = $start;
        while (1) {
            yield $n++;
        }
    }
}

sub fib {
    generator {
        my $n = 0;
        my $m = 1;
        yield $n;
        yield $m;
        while (1) {
            yield $n+$m;
            ($n, $m) = ($m, $n+$m);
        }
    }
}

my $c = count();
for (0..9) {
    say $c->();
}

say;

my $f = fib();
for (0..9) {
    say $f->();
}