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by logicchains 695 days ago
>Async runtimes themselves are simply attempts to bolt-on green threads on top of a language that doesn't support them on a language level.

Haskell supports async code while also supporting green threads on a language level, and the async code has most of the same issues as async code in any other languages.
1 comments
whateveracct 695 days ago
What problems exactly? Haskell has a few things that imo it does better than most languages in this area:

- All IO is non-blocking by default.

- FFI support for interruptible.

- Haskell threads can be preempted externally - this allows you to ensure they never leak. Vs a goroutine that can just spin forever if it doesn't explicitly yield.

- There are various stdlib abstractions for building concurrent programs in a compositional way.

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kbolino 694 days ago
> Haskell threads can be preempted externally - this allows you to ensure they never leak. Vs a goroutine that can just spin forever if it doesn't explicitly yield.

Goroutines are preemptible by the runtime (since https://go.dev/doc/go1.14#runtime) but they're still not addressable or killable through the language itself.

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whateveracct 694 days ago
The GHC runtime has lots of cool concurrency features.

Async exceptions as a way to pass messages (and kill threads!)

Allocation limits for threads.

Software Transactional Memory.

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