kotlin-coro-suspending.kt

package generator

import kotlin.coroutines.*
import kotlin.coroutines.intrinsics.*

fun kotlincoro() = generate<String, String>{
    println("[ coroutine ]: started")
    println("[ coroutine ]: suspended at first yield and sent data to main")
    val coroData = yield("Hello") // yield() causes coroutine to produce value "Hello" for consumer
                                              // and kotlincoro function gets suspended till consumer invokes
                                              // and gets it out of suspension

    println("[ coroutine ]: resumed from first yield")
    println("[ coroutine ]: received { $coroData }")
    println("[ coroutine ]: reached and suspended at 2nd yield and sent data to main")
    val coroNewData = yield("Bye")// yield() causes coroutine to produce value "Bye" for consumer
                                              // and kotlincoro gets suspended till consumer invokes
                                              // and gets it out of suspension

    println("[ coroutine ]: resumed from second yield")
    println("[ coroutine ]: received { $coroNewData }")
    println("[ coroutine ]: ended")
}


fun main(args: Array<String>) {
    val g = kotlincoro() // This will put the generator into created state

    // We send empty string to g.next() to get the generator into suspended state
    // cause there is no point in sending any value in g.next("") till the generator is started and suspended
    val initData = g.next("")   // Will make gen advance till first yield and if there is data, that will be given to consumer
    println("[ In main ]:  { $initData }")
    println("==============================")

    val data = g.next("whats up") // Will make gen advance till second yield and if there is data, that will be given to consumer
    println("[ In main ]: { $data }")
    println("==============================")

    g.next("Howdy there ?")
    println("[In main ] : again")

    g.next("")
}