Oh wow proof of concept open mouth This one runs forever rec kotlinlang #coroutines

suspend fun main() {
    recurse(1)
}


suspend fun recurse(n: Int) {
    if (n % 1000 == 0)
        delay(1)

    println(n)
    recurse(n+1)

    print("")
}

Question is now how to implement that manually, with

@RestrictsSuspension

and without the 1ms penalty 😄 And how to figure out a good

n % something

as it depends on the stack size usage of each function in the call stack.

Ruckus

12/28/2019, 4:52 PM

I can't answer all of your question, but you should at least be able to replace

delay(1)

with

yield()

➕ 1

Marc Knaup

12/29/2019, 1:11 AM

I've tried that, but it always overflows then 🤔

louiscad

12/30/2019, 3:08 PM

@Marc Knaup With which kotlinx.coroutines version and which dispatcher?

Marc Knaup

12/30/2019, 4:13 PM

1.3.3 and whatever dispatcher a

suspend fun main

is using.

louiscad

12/30/2019, 9:18 PM

It's using `Dispatchers.Default`… by default.

Can't you make the function tail recursive?

tailrec

Marc Knaup

12/31/2019, 7:40 AM

No, it’s a complex full-blown visitor pattern, and visitors can do whatever they like 🙂

That’s especially crazy with parallel recursive visitors 😄 start visiting -> visit node X using visitor 1 -> visitor1.visit(X) -> visit children -> visit node X using visitor 2 -> visitor2.visit(X) -> visit children -> visit node Y using visitor 1 -> visitor1.visit(Y) -> visit children -> visit node Y using visitor 2 -> visitor2.visit(Y) -> visit children -> and so on

visit children

and

visit node … using visitor …

are controlled by me.

visitor….visit(…)

can be arbitrary code, by every class that implements a Visitor.

louiscad

01/02/2020, 1:15 PM

I think @orangy or @elizarov did an experiment with such a recursive logic, they might be able to bring some valuable input from their experience.

Marc Knaup

01/02/2020, 1:27 PM

I’ve seen Roman’s work and it goes in the same direction 🙂

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