> Async programming also allows for structured programming, where each task is an owned resource of a parent tasks, which means that lifetimes of tasks can be controlled and runaway threads can't exist
Arguably, structured concurrency as described above is easier to obtain when using threads as your underlying mechanism, because the vast majority of code is serial[1]. That there are a handful of critical regions where you want to express concurrency relationships doesn't mean we have to discard threads. That's throwing the baby out with the bath water.
Self-promotion: I had stumbled on the idea of "nurseries", independently and many years before the above were published. See https://github.com/wahern/cqueues It's nominally a non-blocking "threading" API for Lua. (In Lua coroutines are also called threads.) But note the plural, continuation queues. It's trivial to instantiate a queue, which is similar to a nursery. This was by design. Many cqueues projects naturally end up with a tree of thread controllers/schedulers. It doesn't work on Windows (yet) because it relies on the fact that kqueue, epoll, and Solaris Ports descriptors can be recursively polled.
You're confusing mechanism with semantics. Here's an article on how Java's Project Loom achieves structured concurrency using its new virtual threads capability: https://vorpus.org/blog/notes-on-structured-concurrency-or-g...
And the article cited above that proposes the idea of nurseries for structured concurrency: https://vorpus.org/blog/notes-on-structured-concurrency-or-g...
Arguably, structured concurrency as described above is easier to obtain when using threads as your underlying mechanism, because the vast majority of code is serial[1]. That there are a handful of critical regions where you want to express concurrency relationships doesn't mean we have to discard threads. That's throwing the baby out with the bath water.
Self-promotion: I had stumbled on the idea of "nurseries", independently and many years before the above were published. See https://github.com/wahern/cqueues It's nominally a non-blocking "threading" API for Lua. (In Lua coroutines are also called threads.) But note the plural, continuation queues. It's trivial to instantiate a queue, which is similar to a nursery. This was by design. Many cqueues projects naturally end up with a tree of thread controllers/schedulers. It doesn't work on Windows (yet) because it relies on the fact that kqueue, epoll, and Solaris Ports descriptors can be recursively polled.
[1] Serial != synchronous/blocking.