roschlau

class Event<T> {
    private val handlers = arrayListOf<(T) -> Unit>()
    operator fun plusAssign(handler: (T) -> Unit) { handlers.add(handler) }
    operator fun invoke(value: T) { for (handler in handlers) handler(value) }
}

val e = Event<String>() // define event

fun main(args : Array<String>) {
    e += { println(it) } // subscribe