Announcing Rust 1.27
blog.rust-lang.org
Announcing Rust 1.27
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Re: Announcing Rust 1.27
#2The new syntax for dynamically-dispatched traits, “dyn Trait”, is an example of Rust’s persistently excellent consideration of what should be explicit and what should be implicit. Python’s mantra of “explicit is better than Implicit” mostly captures my general feeling, but you can’t make everything explicit. Back before impl Trait existed, just Box seemed very clear. Now that there’s an important thing to differentiate it from, it seems better to have dyn Trait and impl Trait both prefixed with keywords.
It also makes for much easier googling. ;)
Re: Announcing Rust 1.27
#3SIMD on stable is very exciting news. SIMD unlocks the power of the GPU-esque parallelism that is already inside your CPU. While compilers do try very hard to take advantage of this automatically, it’s not always predictable and can make performance fragile. This is what people are talking about when they refer to “low level control”. Don’t expect that with Rust 1.27 you’ll need to understand SIMD to get anything done. Do expect various libraries to just get faster on stable. For example, BurntSushi, the author of the regex crate and the ripgrep tool, has already enabled it if you’re on Rust 1.27 Stable. [1]
SIMD is another notch towards never needing to use nightly Rust. What this really looks like in practice is that less frequently will a user encounter a fast-mode and a slow-mode for a crate depending on whether they’re using nightly, with all the unstable features enabled, or not.
Re: Announcing Rust 1.27
#4The new syntax for dynamically-dispatched traits, “dyn Trait”, is an example of Rust’s persistently excellent consideration of what should be explicit and what should be implicit. Python’s mantra of “explicit is better than Implicit” mostly captures my general feeling, but you can’t make everything explicit. Back before impl Trait existed, just Box seemed very clear. Now that there’s an important thing to differentia…
> Rust’s trait object syntax is one that we ultimately regret.
Would someone please explain the problem (and the solution) for someone who doesn't know Rust yet?
Re: Announcing Rust 1.27
#5Yes!! I have been waiting for the new time helpers to arrive in stable. It may be a small thing but is so much nicer and makes Rust feel more like a higher level language when I can do `some_time.subsec_millis()` rather than `some_time.subsec_nanos() / 1_000_000`.
Re: Announcing Rust 1.27
#6The new syntax for dynamically-dispatched traits, “dyn Trait”, is an example of Rust’s persistently excellent consideration of what should be explicit and what should be implicit. Python’s mantra of “explicit is better than Implicit” mostly captures my general feeling, but you can’t make everything explicit. Back before impl Trait existed, just Box seemed very clear. Now that there’s an important thing to differentia…
> Rust’s trait object syntax is one that we ultimately regret. Would someone please explain the problem (and the solution) for someone who doesn't know Rust yet?
This thread explains it quite well: https://www.reddit.com/r/rust/comments/8sqiin/newbie_questio...
Re: Announcing Rust 1.27
#7SIMD on stable is very exciting news. SIMD unlocks the power of the GPU-esque parallelism that is already inside your CPU. While compilers do try very hard to take advantage of this automatically, it’s not always predictable and can make performance fragile. This is what people are talking about when they refer to “low level control”. Don’t expect that with Rust 1.27 you’ll need to understand SIMD to get anything don…
How useful is SIMD on CPU these days given that most of the touted original applications (back in the MMX SSE days) have been moved over to GPUs?
Re: Announcing Rust 1.27
#8The new syntax for dynamically-dispatched traits, “dyn Trait”, is an example of Rust’s persistently excellent consideration of what should be explicit and what should be implicit. Python’s mantra of “explicit is better than Implicit” mostly captures my general feeling, but you can’t make everything explicit. Back before impl Trait existed, just Box seemed very clear. Now that there’s an important thing to differentia…
> Rust’s trait object syntax is one that we ultimately regret. Would someone please explain the problem (and the solution) for someone who doesn't know Rust yet?
The linked thread is good, but the short answer:
Box
This change separates the two. Now:
Box
// always a single pointer to a struct (or enum)
Box
// always a double pointer
Box
As an addendum, the parent mentions another feature, "impl Trait", which can be used with traits. Their point was, originally, Box was the only thing that existed like this. With "impl Trait", it was "impl Trait" vs "Trait", and is now "impl Trait" vs "dyn Trait", which is much more clear, at least in many people's opinions. :)
Re: Announcing Rust 1.27
#9SIMD on stable is very exciting news. SIMD unlocks the power of the GPU-esque parallelism that is already inside your CPU. While compilers do try very hard to take advantage of this automatically, it’s not always predictable and can make performance fragile. This is what people are talking about when they refer to “low level control”. Don’t expect that with Rust 1.27 you’ll need to understand SIMD to get anything don…
How useful is SIMD on CPU these days given that most of the touted original applications (back in the MMX SSE days) have been moved over to GPUs?
Still really useful. We use NEON on Android all the time since there's not a great API there and spinning up a GPU on a mobile device is not something you want to do unless you absolutely have to.
Re: Announcing Rust 1.27
#10SIMD on stable is very exciting news. SIMD unlocks the power of the GPU-esque parallelism that is already inside your CPU. While compilers do try very hard to take advantage of this automatically, it’s not always predictable and can make performance fragile. This is what people are talking about when they refer to “low level control”. Don’t expect that with Rust 1.27 you’ll need to understand SIMD to get anything don…
How useful is SIMD on CPU these days given that most of the touted original applications (back in the MMX SSE days) have been moved over to GPUs?
Well, it seems pretty useful - e.g. it helps make ripgrep fast, it can speed up regex. There's a lot it can make faster. How much faster, I'm not sure.