How to access class methods from anonymous suspend function inside constructor in kotlin? - kotlin

Question

I want to be able to call functions from the anonymous constructor's suspend function in the following example:
data class SuspendableStep(
val condition: SuspendableCondition,
val continuation: Continuation<Unit>
)
class WaitCondition(cycles: Int) : SuspendableCondition() {
private val timer = SomeTimer(cycles)
override fun resume(): Boolean = timer.elapsed() // timer is handled somewhere else
override fun toString(): String = "WaitCondition_$timer"
}
class BasicContinuation : Continuation<Unit> {
var coroutine: Continuation<Unit>
override val context: CoroutineContext = EmptyCoroutineContext
private var nextStep: SuspendableStep? = null
constructor(task: suspend () -> Unit) {
coroutine = task.createCoroutine(completion = this)
}
override fun resumeWith(result: Result<Unit>) {
nextStep = null
result.exceptionOrNull()?.let { e -> Logger.handle("Error with plugin!", e) }
}
suspend fun wait(cycles: Int): Unit = suspendCoroutine {
check(cycles > 0) { "Wait cycles must be greater than 0." }
nextStep = SuspendableStep(WaitCondition(cycles), it)
}
}
fun main() {
BasicContinuation({
println("HELLO")
wait(1)
println("WORLD")
}).coroutine.resume(Unit)
}
There only other option I found was to override a suspend function by creating an anonymous inner class and calling another function to set the coroutine:
fun main() {
val bc = BasicContinuation() {
override suspend fun test() : Unit {
println("HELLO")
wait(1)
println("WORLD")
}
}
bc.set() // assign coroutine to suspend { test }.createCoroutine(completion = this)
bc.coroutine.resume(Unit)
}

Answer 1

I used CoroutineScope to extend the scope of the functions I could access:
class BasicContinuation : Continuation<Unit> {
var coroutine: Continuation<Unit>
override val context: CoroutineContext = EmptyCoroutineContext
private var nextStep: SuspendableStep? = null
constructor(task: (suspend BasicContinuation.(CoroutineScope) -> Unit)) {
coroutine = suspend { task.invoke(this, CoroutineScope(context)) }.createCoroutine(completion = this)
}
override fun resumeWith(result: Result<Unit>) {
nextStep = null
result.exceptionOrNull()?.let { e -> Logger.handle("Error with plugin!", e) }
}
suspend fun wait(cycles: Int): Unit = suspendCoroutine {
check(cycles > 0) { "Wait cycles must be greater than 0." }
nextStep = SuspendableStep(WaitCondition(cycles), it)
}
}
fun main() {
val bc = BasicContinuation({
println("Hello")
wait(1)
println("World")
})
bc.coroutine.resume(Unit) // print "Hello"
// increment timer
bc.coroutine.resume(Unit) // print "World
}