Hacker News Reader

Comment by demallien | Hacker News Reader

Async IO without the callbacks? How does that work???

Green threads in Haskell do this too.

You can write code in typical imperative fashion but all blocking IO statements will cause a co-operative green thread switch.

Rust was also experimenting with green threads and similar async IO but they recently changed to use all-native threads.

> Rust was also experimenting with green threads and similar async IO but they recently changed to use all-native threads.

tasks can be either 1:1[0] or m:n[1]. The default is 1:1, but m:n should be equally supported by force-booting with libgreen[2].

[0] http://doc.rust-lang.org/native/index.html [1] http://doc.rust-lang.org/green/ [2] http://doc.rust-lang.org/guide-runtime.html#force-booting-wi...

>Rust was also experimenting with green threads and similar async IO but they recently changed to use all-native threads.

I'm pretty sure that I/O is only task-blocking in Rust, and tasks can be 1:1 or M:N with native threads.

That's correct, but there's not much reason to use green threads in Rust--they don't have the advantages that green threads in Go do, besides the lack of context switching (they aren't "lightweight" because they are just as resource-intensive as threads).

Lightweight threads in Haskell (using the excellent GHC runtime).

Coroutines. Er, I mean, "goroutines".

You can even do it in C (if you REALLY want) http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html

The way async is supposed to. From coroutines to await etc.

Reply on news.ycombinator.com