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The same approach can and does exist in Rust too, e.g. https://crates.io/crates/mioco https://crates.io/crates/mioco . (Concurrency in C and C++ is also third-

by dbaupp 11y ago

The same approach can and does exist in Rust too, e.g. https://crates.io/crates/mioco https://crates.io/crates/mioco . (Concurrency in C and C++ is also third-party libraries... The whole point of languages like Rust and C++ is that powerful functionality like this can be built externally, so that different trade-offs can be made. Languages like Go and Node force one approach, and so when you need something outside it, you're forced to do something suboptimal.)

acconsta 11y ago
>The same approach can and does exist in Rust Without the documentation, stability, portability, quality guarantees, and compiler support (that's a big one — code generation for coroutines needs to be good) of a standard library. >Concurrency in C and C++ is also third-party libraries C++ is on track to standardize concurrent file and network IO. Draft specifications have already been published, and Microsoft shipped coroutines in VS 2015. It would be a damn shame if C++ got concurrent IO before Rust. I would like to use Rust professionally, and I'm sure you do/would as well. But no one can possibly sell their boss on using a project with a single part time maintainer to provide critical functionality.
- dbaupp 11y ago
  The C/C++ libraries you're holding up as examples get no compiler support. That said, I do think a much better style of coroutines for Rust would be a C#-esque async/await transformation, converting stack-frames/local variables into an enum, allowing literally zero-cost coroutines (all the state is stored inline, no need to allocate a separate stack). Relevant issues: - https://github.com/rust-lang/rfcs/issues/388 https://github.com/rust-lang/rfcs/issues/388 - https://github.com/rust-lang/rfcs/issues/1081 https://github.com/rust-lang/rfcs/issues/1081 I'm pretty sure this is quite non-trivial to implement automatically. --- C++ has had 20 years of stability, Rust only 3 months. Rust will get concurrent IO before C++ has on that time scale. The goal with 1.0 was to stabilise enough of the language that people can start using it to write libraries that work into the forseeable future, allowing them to seriously explore the space of, for example, concurrent IO in Rust. Once enough exploration has been done (maybe you think enough has been done for async IO now), the functionality can start to become more official.
  - acconsta 11y ago
    >The C/C++ libraries you're holding up as examples get no compiler support. You can open VS 2015 today and use C++ coroutines backed by Microsoft (and their compiler, which is developed alongside their standard library). And I am by no means saying that Goroutines are the final story in concurrent IO. Stackless coroutines in Rust would be a dream. >C++ has had 20 years of stability, Rust only 3 months. Rust will get concurrent IO before C++ has on that time scale. Concurrent IO is a hell of lot more important than it was in the 1990s, and the relative timescale is irrelevant for people choosing between Rust and C++ today (or Go, Scala, Clojure, C#, etc.). >Once enough exploration has been done (maybe you think enough has been done for async IO now), Exactly the opposite — I think the number of developers working on this (the Mio author plus Alex Crichton, maybe some offshoots) is far too few. And the attitude I'm seeing from some core developers in this thread (concurrent IO is a "pet" feature that the community will someday deliver fully formed and ready for "blessing") is a huge disappointment.
    - dbaupp 11y ago
      Rust is targeting more than one domain. Concurrent IO is not important in all domains. I'm sure the domains you work in need it a lot, but that's not the whole world. (This is all I mean by "pet feature".) There are cross-cutting concerns that apply to everything (including concurrent IO libraries) that development work is focusing on. Rust doesn't need to eat Go's/Scala's/Clojure's... lunch 3 months after it was released, taking a year or two to settle in and branch out seems fine to me.
      - acconsta 11y ago
        >Rust is targeting more than one domain. Concurrent IO is not important in all domains. Well, what domains is Rust targeting? Rust still isn't a good fit for embedded/kernel stuff without allocators and OOM handling (not to mention every architecture not targeted by LLVM). That leaves userland applications, and how many applications don't need concurrent IO? I'm definitely being impatient, and I'm sorry for that. It's just frustrating to see only one core member working on it.

by dbaupp 11y ago

acconsta 11y ago

>The same approach can and does exist in Rust Without the documentation, stability, portability, quality guarantees, and compiler support (that's a big one — code generation for coroutines needs to be good) of a standard library. >Concurrency in C and C++ is also third-party libraries C++ is on track to standardize concurrent file and network IO. Draft specifications have already been published, and Microsoft shipped coroutines in VS 2015. It would be a damn shame if C++ got concurrent IO before Rust. I would like to use Rust professionally, and I'm sure you do/would as well. But no one can possibly sell their boss on using a project with a single part time maintainer to provide critical functionality.

dbaupp 11y ago
The C/C++ libraries you're holding up as examples get no compiler support. That said, I do think a much better style of coroutines for Rust would be a C#-esque async/await transformation, converting stack-frames/local variables into an enum, allowing literally zero-cost coroutines (all the state is stored inline, no need to allocate a separate stack). Relevant issues: - https://github.com/rust-lang/rfcs/issues/388 https://github.com/rust-lang/rfcs/issues/388 - https://github.com/rust-lang/rfcs/issues/1081 https://github.com/rust-lang/rfcs/issues/1081 I'm pretty sure this is quite non-trivial to implement automatically. --- C++ has had 20 years of stability, Rust only 3 months. Rust will get concurrent IO before C++ has on that time scale. The goal with 1.0 was to stabilise enough of the language that people can start using it to write libraries that work into the forseeable future, allowing them to seriously explore the space of, for example, concurrent IO in Rust. Once enough exploration has been done (maybe you think enough has been done for async IO now), the functionality can start to become more official.
- acconsta 11y ago
  >The C/C++ libraries you're holding up as examples get no compiler support. You can open VS 2015 today and use C++ coroutines backed by Microsoft (and their compiler, which is developed alongside their standard library). And I am by no means saying that Goroutines are the final story in concurrent IO. Stackless coroutines in Rust would be a dream. >C++ has had 20 years of stability, Rust only 3 months. Rust will get concurrent IO before C++ has on that time scale. Concurrent IO is a hell of lot more important than it was in the 1990s, and the relative timescale is irrelevant for people choosing between Rust and C++ today (or Go, Scala, Clojure, C#, etc.). >Once enough exploration has been done (maybe you think enough has been done for async IO now), Exactly the opposite — I think the number of developers working on this (the Mio author plus Alex Crichton, maybe some offshoots) is far too few. And the attitude I'm seeing from some core developers in this thread (concurrent IO is a "pet" feature that the community will someday deliver fully formed and ready for "blessing") is a huge disappointment.
  - dbaupp 11y ago
    Rust is targeting more than one domain. Concurrent IO is not important in all domains. I'm sure the domains you work in need it a lot, but that's not the whole world. (This is all I mean by "pet feature".) There are cross-cutting concerns that apply to everything (including concurrent IO libraries) that development work is focusing on. Rust doesn't need to eat Go's/Scala's/Clojure's... lunch 3 months after it was released, taking a year or two to settle in and branch out seems fine to me.
    - acconsta 11y ago
      >Rust is targeting more than one domain. Concurrent IO is not important in all domains. Well, what domains is Rust targeting? Rust still isn't a good fit for embedded/kernel stuff without allocators and OOM handling (not to mention every architecture not targeted by LLVM). That leaves userland applications, and how many applications don't need concurrent IO? I'm definitely being impatient, and I'm sorry for that. It's just frustrating to see only one core member working on it.