RustLatam 2019 - Without Boats: Zero-Cost Async IO

The nuances in this case went well beyond what I was expecting - it's actually more than just syntax, this heavily crosses over into semantics. It's been a very impressive process, and I was surprised at the power of the solution they landed on. - Rust has to find a syntax that can work with different underlying libraries (Rust can compile to lots of different targets, some will have capability to accommodate larger libraries than others) - The abstraction can't incur undue overhead (callback-based solutions may cause allocations that are hard to keep under control and will split the language if it spreads too much) - The syntax should be pleasant to write for at least the majority of people (modeling your entire application as a state machine around async computation is pretty unpleasant) - The compiler has to be able to give helpful error messages (this was a problem early on I think) - Language authors had to think about how the borrow checker would work across async points, and whether to invest in changing the language to make that possible. - and so on and so on I really loved this talk by Without Boats (the author of the friendly article) going over all this stuff, really gave me a good sense of what they were up against [this video]

That document isn't about arguing one way or the other, it lists all the different options and pros/cons. The post thread is the current stance of the lang team and letting everyone know they're going to make the final decision later this month. Boats' keynote at rust-latam goes into some more detail as well. [this video] I'm just a casual observer here, but it seems like just about every argument and position on the subject has been iterated across Github, internals.rust-lang.org, the IRC/Discourse/Zulip chats, Reddit, and now HN. This post by boats is just the next stepping stone alerting the community to the direction the team is leading and that it's going to be over soon.