There really is no way to avoid passing the channel as an argument and avoid `produce` ? I don't wan...

# coroutines

[Carrascado]

There really is no way to avoid passing the channel as an argument and avoid produce ? I don't want to avoid produce, it's just for curiosity

[octylFractal]

not if you don't want it to take a CoroutineScope

[Carrascado]

Umm I don't see it

[octylFractal]

what do you mean?

[Carrascado]

How could you do it passing a coroutinescope?

[Andrea Giuliano]

I think you can do like in this example
https://github.com/kotlin/kotlinx.coroutines/blob/master/kotlinx-coroutines-core/jvm/test/guide/example-channel-03.kt

[octylFractal]

you would basically re-implement produce

[Andrea Giuliano]

I believe the only limitation with that is that it’s valid when you have a single coroutine that is producing multiple values. If instead you have multiple coroutines producing values and you want to collect them all then I guess using channels is fine

[octylFractal]

fun CoroutineScope.produceSquares(): ReceiveChannel<Int> {
  val channel = Channel<Int>()
  launch {
      for (x in 1..5) channel.send(x * x)
      channel.close()
  }
  return channel
}

[octylFractal]

there it is without produce, but it's way less safe than what produce gives you

[Carrascado]

Oh I see, that's clever. Thank you guys

[Carrascado]

It was out of curiosity anyways, I'm gonna use produce 😂

[Andrea Giuliano]

it’s interesting though how, if you change the example code to this

suspend fun produceSquares(): ReceiveChannel<Int> = coroutineScope {
        produce {
            for (x in 1..5) {
                send(x * x)
            }
        }
    }

so in practice you are not making produceSquare an extension function for CoroutineScope the code blocks after sending the first item in the channel. As if in the original example the channel gets created with the right side while in this snippet it gets created with 0 capacity?
Anyone knows why?

[octylFractal]

you understand how coroutineScope works, right? it suspends until all child coroutines complete, which includes produce

[Andrea Giuliano]

right! I always forget that! 😄

[Andrea Giuliano]

that’s interesting though, so if you make an extension function of CoroutineScope, you remove the waiting part and the coroutines gets launched still in the same scope, but the function won’t wait.. interesting..

[octylFractal]

well, it's technically a different scope, the scope of whatever's calling the function

[Andrea Giuliano]

true, instead of being a child scope