blog-comments VS async-trait

This was a great article, very easy to understand without leaving out the fundamental pieces (the saga that is async implementation difficulty). I think I can even boil this situation down to Rust having it's Monad moment.

It's in this (HN) comment thread and a bunch of informed comments on the original article:

https://github.com/eeeeeta/blog-comments/issues/10#issuecomm...

https://github.com/eeeeeta/blog-comments/issues/10#issuecomm...

https://github.com/eeeeeta/blog-comments/issues/10#issuecomm...

The comments are correct in my view -- Rust can't/shouldn't do what Haskell did, which was to create use a general purpose abstraction that is essentially able to carry "the world" (as state) along with easy-to-trade chained functions on that state (whenever it gets realized). Haskell might have solved the problem, but it has paid a large price in language difficulty (perceived or actual) because of it, not mentioning the structural limitations of what Rust can do and it's constraints. The trade-off just isn't worth it for the kind of language Rust aims to be.

Realistically, I think this issue is big but not enough to write off rust for me personally (as the author seems to have) -- I'd just do the move + Arc shenanigans because if you've been building java applications with IoC and/or other patterns that generally require global-ish singletons (given example was a DB being used by a server), this isn't the worst complexity trade-off you've had to make, though the Rust compiler is a lot more ambitious, and Rust has a cleaner, better, more concise type system as far as I'm concerned.

I think another thing I've gained from this article is another nice little case where Haskell (if you've taken the time to grok it sufficiently, which can be a long time) offers a bit of a nicer general solution than Rust, assuming you were in a world where those two were actually even substitutes. In the much more likely world where you might compare Rust and Go2, this might be a win for Go2, but the rest of the language features would put rust on top for me.

As of today, async functions in traits are not natively supported by Rust. Fortunately, David Tolnay got our back covered (one more time): we can use the async-trait crate.

You might want to check out https://github.com/dtolnay/async-trait to be able to declare async functions in a trait.

Also async-trait (GitHub), dtolnay has done some great work!

Does async-trait count as a trick or hack? It's not my hack, but it's a workaround/hack that I use every single day.

This macro goes a very long way toward solving the problem: https://github.com/dtolnay/async-trait

I'm still learning async to I cannot answer all the questions. First of all, I use this -> https://github.com/dtolnay/async-trait to take care of the async-inside-traits mess.