swift event

class Event<T> {
    typealias subscriber = (T)->Void
    var subscribers = subscriber[]()
    func subscribe(body : subscriber) {
        subscribers.append(body)
    }
    func fire(value : T) {
        for s in subscribers {
            s(value)
        }
    }
}

@assignment func += <T> (inout event: Event<T>, body: (T)->Void) {
    event.subscribe(body)
}

var e = Event<Int>()
e += { value in println(value) }

e.fire(1)