What do you guys think about this function? It all...

# coroutines

[vaskir]

What do you guys think about this function? It allow to define concurrently running jobs:

class ParallelBuilder<T> {
    private val coroutines = ArrayList<Deferred<T>>()

    fun prun(context: CoroutineContext = CommonPool,
             start: CoroutineStart = CoroutineStart.DEFAULT,
             block: suspend CoroutineScope.() -> T) {
        coroutines.add(async(context, start, block))
    }

    suspend fun resume() = coroutines.map { it.await() }
}

inline suspend fun <R> parallel(crossinline builder: ParallelBuilder<R>.() -> Unit): List<R> {
    val scope = ParallelBuilder<R>()
    scope.builder()
    return scope.resume()
}

fun main(args: Array<String>) = runBlocking {
    val res = parallel<Int> {
        prun {
            println("1")
            delay(1000)
            println("1 done")
            1
        }

        prun {
            println("2")
            delay(1000)
            println("2 done")
            2
        }

        prun {
            println("3")
            delay(1000)
            println("3 done")
            3
        }
    }
}

output

1
2
3
2 done
3 done
1 done
Result: [1, 2, 3]

I suspect there are a number of such functions already written 🙂 However, I didn't find one in the standard lib.