Async Rust Is A Bad Language (
from to on 08 Sep 2023 19:10 +0000

#rust on 08 Sep 2023 19:46 +0000 next

fn foo(&big, &chungus)

is out,

async fn foo(&BIG_GLOBAL_STATIC_REF_OR_SIMILAR_HORROR, sendable_chungus.clone())

is in.

Or maybe you know

fn foo(&big, &chungus)

is out

async fn foo(big, chungus) -> (big, chungus)

is in


async fn foo(big, chungus) {
  // ...
  tx.send((big, chungus)).await?;
  // ...

is in

Moving (movable/sendable) data is not limited by number or direction, you know. And that second one even makes use of them great Hoare channels! And gives us control on how long we hold on to data before sending it back (modified or not). But I digress. Let’s go back to the important talking point that Hoare was right! on 09 Sep 2023 18:16 +0000

I think the point of the “BIG_GLOBAL_STATIC…” name is that global statics are bad, not that the syntax is ugly. That said, you’re absolutely correct that combining channels with async code is the way to go. on 09 Sep 2023 18:49 +0000

I think the point of the “BIG_GLOBAL_STATIC…” name is that global statics are bad, not that the syntax is ugly.

Yes. And my point was that there is an obvious way of sharing data besides passing static-refs, cloning, and using Arcs, which is moving data bidirectionally. That was conveniently, or ignorantly, glossed over by the coping gopher. on 08 Sep 2023 20:24 +0000 next

Good read! on 08 Sep 2023 23:00 +0000 next

Interesting read but I don’t agree that it’s as bad as the author makes it sound. I’m also curious what an alternative would be, if you don’t want a garbage collector?

In my personal experience, you don’t run into all the Arc, Pin and 'static stuff that often. I would even say very rarely. on 09 Sep 2023 06:27 +0000

I agree, I’ve written a lot of async rust and it’s rarely an issue for me. I have more issues with the generated futures and the traits they implement not matching what I need, meaning I often have to jump to manually created futures and pin-project (which isn’t too bad tbh but far more work than writing with async/await). on 09 Sep 2023 05:29 +0000 next

Async rust might suck, compared to async in higher level languages, but for someone comming from C, async rust simplifies a lot of stuff. It often feels like a lot of criticisms of rust boils down to the fact that rist was sold to both people using low and high level languages. I don’t doubt that async rust is shit when all you want is a faster typescript.

Edit: I certainly also have my criticisms of rust and its async implementation, and I think some of the authors concerns are valid, it was just an observation about the tension between the needs of the two groups of users. on 09 Sep 2023 05:56 +0000 next

It really is interesting how async Rust takes the shine off of Rust to such an extent. If good old stack based, single threaded Rust wasn’t so polished, I don’t think the async parts would stand out so much. Something that might help is to have some sort of benchmark showing that Arcing through an async problem is still faster than typical GCed languages. on 09 Sep 2023 08:25 +0000 next

Maybe it’s just me, but isn’t async programming a mess in all programming languages? on 09 Sep 2023 08:48 +0000

It’s a joy to do async in go IMO on 09 Sep 2023 13:44 +0000 next

To be fair, a lot of that is because the scheduler detects blocking IO and context switches.

Rust could get really far with Go-style channels. on 09 Sep 2023 16:40 +0000

Are Go-style channels different from what Tokio provides? on 10 Sep 2023 03:56 +0000

They’re very similar, but with very different ergonomics. Go channels are part of the language, so libraries use them frequently, whereas tokio is a separate library and not nearly as ubiquitous. So you’ll get stuff like this:

c := make(chan bool)
go func () {
    c <- true
} ()

select {
case val := <-c:
case _ := <-time.After(time.Second)

This lets you implement a simple timeout for a channel read. So the barrier to using them is really low, so they get used a ton.

I haven’t looked at the implementation of tokio channels, so I don’t know if there’s something subtly different, but they do have the same high level functionality. on 09 Sep 2023 17:12 +0000 next

That’s a whole different thing to me. That’s not async, that’s channels and multithreading.

I do that in Rust as well with mcsp channels and it’s been fine.

It’s the async/await bit that I find incredibly akward all the time. on 10 Sep 2023 04:13 +0000

Channels and multithreading are a solution to async problems. Instead of a keyword trying to abstract away the async, you use a mechanism for communicating between coroutines. You can run Go with a single execution thread and still get benefits from goroutines and channels. In fact, Go didn’t turn on multithreading until 1.5.

Go solves async with goroutines and channels, not with an async keyword. The runtime is pretty heavy and steps in when standard library functions would block. In other words, it’s async by default since blocking IO causes another goroutines to execute. on 09 Sep 2023 18:47 +0000

not really. first of all async in not the same as threading. And even then, while it makes parallel code easier to write (not easier to reason about), it still has the exact same footguns as anything else, as soon as you venture away from having only one consumer for every producer. Synchronization is still all on you on 09 Sep 2023 14:06 +0000

<img alt="" src=""> on 10 Sep 2023 05:28 +0000 next

Zig’s approach seems even more low-level and manual:

(In general, I think Rust and Zig both seem valuable, and I think it’s a mistake to treat programming language success as a zero-sum game.) on 10 Sep 2023 18:41 +0000 next

Mf’s have no sense of humor here…

Or… at least MY sense of humor. on 10 Sep 2023 18:43 +0000

Also, my meme was based on I didn’t randomly pick zig.