A supply sample

supply.p6

#!/usr/bin/env perl6

sub start-server(Supply $s, &operator --> Supply) {
	supply {
		sub server() {
			whenever $s -> $msg {
				if $msg ~~ Int || (try so $msg.Int) {
					emit &operator($msg.Int);
				} else {
					die "Need an integer!";
				}
			}
		}
		server();
	}
}

sub auto-restart(Supply $s --> Supply) {
	supply {
		sub auto() {
			whenever $s -> $msg {
				say "RESULT => " ~ $msg;
				QUIT {
					default {
						.note;
						"Ready to restart server".say;
						auto();
					}
				}
			}
		}
		auto();
	}
}

my $supplier = Supplier.new;
my $supply   = $supplier.Supply;
my $server   = start-server($supply, -> $v { 2 * $v.Int });
my $s        = auto-restart($server);

$s.tap;

while (my $get = prompt("Input a number:")) {
	$supplier.emit($get);
}