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Python has had async for 10 years – why isn't it more popular?

(tonybaloney.github.io)
320 points willm | 1 comments | 02 Sep 25 17:24 UTC | HN request time: 0.331s | source
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atomicnumber3 ◴[02 Sep 25 17:41 UTC] No.45106455[source]▶
The author gets close to what I think the root problem is, but doesn't call it out.

The truth is that in python, async was too little, too late. By the time it was introduced, most people who actually needed to do lots of io concurrently had their own workarounds (forking, etc) and people who didn't actually need it had found out how to get by without it (multiprocessing etc).

Meanwhile, go showed us what good green threads can look like. Then java did it too. Meanwhile, js had better async support the whole time. But all it did was show us that async code just plain sucks compared to green thread code that can just block, instead of having to do the async dances.

So, why engage with it when you already had good solutions?

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1. hinkley ◴[02 Sep 25 20:59 UTC] No.45108978[source]▶
Async is pretty good “green threads” on its own. Coroutines can be better, but they’re really solving an overlapping set of problems. Some the same, some different.

In JavaScript async doesn’t have a good way to nice your tasks, which is an important feature of green threads. Sindre Sorhus has a bunch of libraries that get close, but there’s still a hole.

What coroutines can do is optimize the instruction cache. But I’m not sure goroutines entirely accomplish that. There’s nothing preventing them from doing so but implementation details.