```kotlin interface Greeter fun greet class HappyGreeter Gre kotlinlang #announcements

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Title

p

Paul Woitaschek

06/06/2019, 12:56 PM

kotlin
interface Greeter {
  fun greet()
}

class HappyGreeter : Greeter {
  override fun greet() {
    println("hello :)")
  }
}

class SadGreeter : Greeter {
  override fun greet() {
    println("hello :(")
  }
}

class GreeterDelegate (val greeters : List<Greeter>): Greeter by greeters

d

diesieben07

06/06/2019, 12:59 PM

How would this even work? What if

greet

returns something?

m

marstran

06/06/2019, 12:59 PM

What would the

greet

function do in

GreeterDelegate

? Call

greet

on all elements of

greeters

?

p

Paul Woitaschek

06/06/2019, 1:00 PM

@diesieben07 Right, didn't think of this. My use case is that for analytics I have an interface with multilpe functions for tracking. Now I want to have multiple implementations of that interface for different providers (google analytics, firebase analytics for example)

Hm, this will do:

class GreeterDelegate(val greeters: List<Greeter>) {

  fun execute(action: Greeter.()->Unit) {
    greeters.forEach {
      action(it)
    }
  }
}

fun test(delegate: GreeterDelegate) {
  delegate.execute(Greeter::hello)
}

k

kralli

06/06/2019, 1:16 PM

Btw how do paste a Snippet here? It only lets me paste it in the channel.

k

karelpeeters

06/06/2019, 1:19 PM

https://superuser.com/a/1323804/580758

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