gistfile1.txt

use v6;

role Signal {
        has @.slots; # a nice list of callbacks (that are methods)

        multi method connect(Any:D $rcpt, Method $method){
                @.slots.push([self, $rcpt, $method]);
        }

}

multi trait_mod:<is>(Routine $_signal, :$signal!){
        $_signal does Signal;

        $_signal.slots; # WORKAROUND RT112666

        multi handle_call($args, [ Signal $s, Any:D $receiver, Method $slot ]){
                $slot($receiver, |$args);
        }

        $_signal.wrap(sub (+$args) {
                handle_call($args, $_) for $_signal.slots;
#                           ^^^^^ HERE BE DRAGONS, big ugly sefault
#                           |$args does not segfault
        });
}

multi sub connect(Signal $signal, Any:D $rcpt, Method $slot){
        $signal.connect($rcpt, $slot);
}

class App {
        our method exit { say "App::exit called" }
}

my App $app .= new;

sub bare_signal_exit is signal {}

connect(&bare_signal_exit, $app, &App::exit);

bare_signal_exit;