I wrote an unrolled switch statement in Java to simulate eager async/await across threads.

https://github.com/samsquire/multiversion-concurrency-contro...

The goal is that a compiler should generate this for you. This code is equivalent to the following:

   task1:
     while True:
       handle1 = async task2();
       handle2 = async task3();
       print(await handle1)
       print(await handle2)

   task2:
     n = 0
     while True:
       yield n++

   task3:
     n = 0
     while True:
       yield n++

It doesn't actually run task2 and task3 both eagerly, I've not got around to scheduling the tasks on DIFFERENT threads. They currently queue onto a single thread, so task2 and task3 are parallel to task1 but task2 and task3 are not parallel to each other. This is my goal.

I also ported the coroutines in this blog post https://blog.dziban.net/coroutines/ to GNU Assembler https://github.com/samsquire/assembly/blob/main/coroutines.S

This might be useful to someone who wants to port this to C. This uses the stack switching idea. So they are stackful coroutines.

There's also Tina a header only coroutine library https://slembcke.github.io/Tina

I also played with protothreads http://dunkels.com/adam/pt/

I also asked in a stackoverflow post how to use a thread pool with C++20 coroutines: https://stackoverflow.com/questions/74520133/how-can-i-pass-... Someone provided some example code, which seems to work with C++ coroutines :-)