Zlib-rs is faster than C

> they've been sitting in nightly unstable for years

So many very useful features of Rust and its core library spend years in "nightly" because the maintainers of those features don't have the discipline to see them through.

simd and allocator_api are the two that irritate me enough to consider a different language for future systems dev projects.

I don't have the personality or time to wade into committee type work, so I have no idea what it would take to get those two across the finish line, but the allocator one in particular makes me question Rust for lower level applications. I think it's just not going to happen.

If Zig had proper ADTs and something equivalent to borrow checker, I'd be inclined to poke at it more.

Before I started working with Rust, I spent a lot of time using Swift for systems-y/server-side code, outside of the Apple ecosystem. There is a lot I like about that language, but one of the biggest factors that drove me away was just how fast the Apple team was to add more and more compiler-magic features without considering whether they were really the best possible design. (One example: adding compiler-magic derived implementations of specific protocols instead of an extensible macro system like Rust has.) When these concerns were raised on the mailing lists, the response from leadership was "yes, something like that would be better in the long run, but we want to ship this now." Or even in one case, "yes, that tweak to the design would be better, but we already showed off the old design at the WWDC keynote and we don't want to break code we put in a keynote slide."

When I started working in Rust, I'd want some feature or function, look it up, and find it was unstable, sometimes for years. This was frustrating at first, but then I'd go read the GitHub issue thread and find that there was some design or implementation concern that needed to be overcome, and that people were actively working on it and unwilling to stabilize the feature until they were sure it was the best possible design. And the result of that is that features that do get stabilized are well thought out, generalize, and compose well with everything else in the language.

Yes, I really want things like portable SIMD, allocators, generators, or Iterator::intersperse. But programming languages are the one place I really do want perfect to be the enemy of good. I'd rather it take 5+ years to stabilize features than for us to end up with another Swift or C++.

> the response from leadership was "yes, something like that would be better in the long run, but we want to ship this now."

Sounds like the Rust's async story.

Async went through years of work before being stabilized. This isn't true.

Rust's async model was shipped as an MVP, not in the sense of "this is a bad design and we just want to ship it"; but rather, "we know this is the first step of the eventual design we want, so we can commit to stabilizing these parts of it now while we work on the rest." There's ongoing work to bring together the rest of the pieces and ergonomics on top of that foundational model; async closures & trait methods were recently stabilized, and work towards things like pin ergonomics & simplifying cheap clones like Rc are underway.

Rust uses this strategy of minimal/incremental stabilization quite often (see also: const generics, impl Trait); the difference between this and what drove me away from Swift is that MVPs aren't shipped unless it's clear that the design choices being made now will still be the right choices when the rest of the feature is ready.

IMO shipping async without a standardized API for basic common async facilities (like thread spawning, file/network I/O) was a mistake and basically means that tokio has eaten the whole async side of the language.

Why define runtime independence as a goal, but then make it impossible to write runtime agnostic crates?

(Well, there's the "agnostic" crate at least now)

My personal opinion is that if you want to contribute a language feature, shit or get off the pot. Leaving around a half-baked solution actually raises the required effort for someone who isn't you to add that feature (or an equivalent) because they now have to either (1) ramp up on the spaghetti you wrote or (2) overcome the barrier of explaining why your thing isn't good enough. Neither of those two things are fun (which is important since writing language features is volunteer work) and those things come in the place of doing what is actually fun, which is writing the relevant code.

The fact that the Rust maintainers allow people to put in half-baked features before they are fully designed is the biggest cultural failing of the language, IMO.

>The fact that the Rust maintainers allow people to put in half-baked features before they are fully designed is the biggest cultural failing of the language, IMO.

In nightly?

Hard disagree. Letting people try things out in the real world is how you avoid half-baked features. Easy availability of nightly compilers with unstable features allows way more people to get involved in the pre-stabilization polishing phase of things and raise practical concerns instead of theoretical ones.

C++ takes the approach of writing and nitpicking whitepapers for years before any implementations are ready and it's hard to see how that has led to better outcomes relatively speaking.

Yeah, we're going to have to agree to disagree on the C++ flow (really the flow for any language that has a written standard) being better. That flow is usually:

1. Big library/compiler does a thing, and people really like it

2. Other compilers and libraries copy that thing, sometimes putting their own spin on it

3. All the kinks get worked out and they write a white paper

4. Eventually the thing becomes standard

That way, everything in the standard library is something that is fully-thought-out and feature-complete. It also gives much more room for competing implementations to be built and considered before someone stakes out a spot in the standard library for their thing.

>IMO shipping async without a standardized API for basic common async facilities (like thread spawning, file/network I/O) was a mistake and basically means that tokio has eaten the whole async side of the language.

I would argue that it's the opposite of a mistake. If you standardize everything before the ecosystem gets a chance to play with it, you risk making mistakes that you have to live with in perpetuity.

>That way, everything in the standard library is something that is fully-thought-out and feature-complete

Are C++ features really that much better thought out? Modules were "standardized" half a decade ago, but the list of problems with actually using them in practice is still pretty damn long to the point where adoption is basically non-existent.

I'm not going to pretend to be nearly as knowledgeable about C++ as Rust, but it seems like most new C++ features I hear about are a bit janky or don't actually fit that well with the rest of the language. Something that tends to happen when designing things in an ivory tower without testing them in practice.

They absolutely are. The reason many features are stupid and janky is because the language and its ecosystem has had almost 40 more years to collect cruft.

The fundamental problem with modules is that build systems for C++ have different abstractions and boundaries. C++ modules are like Rust async - something that just doesn't fit well with the language/system and got hammered in anyway.

The reason it seems like they come from nowhere is probably because you don't know where they come from. Most things go through boost, folly, absl, clang, or GCC (or are vendor-specific features) before going to std.

That being said, it's not just C++ that has this flow for adding features to the language. Almost every other major language that is not Rust has an authoritative specification.

What's a Rust feature that you think suffered from their process in a way that C++ would not have?

generic simd abstractions are of quite limited use. I'm not sure what's objectionable about the thing Rust has shipped (in nightly) for this, which is more or less the same as the stuff Zig has shipped for this (in a pre-1.0 compiler version).

> maintainers of those features don't have the discipline to see them through.

This take makes me sad. There are a lot of reasons why an open source contributor may not see something through. "Lack of discipline" is only one of them. Others that come to mind are: lack of time, lack of resources, lack of capability (i.e good at writing code, but struggles to navigate the social complexities of sheparding a significant code change), clinically impaired ability to "stay the course" and "see things through" (e.g. ADHD), or maybe it was a collaborative effort and some of the parties dropped out for any of the aforementioned reasons.

I don't have a solution, but it does kinda suck that open source contribution processes are so dependent on instigators being the responsible party to seeing a change all the way through the pipeline.

Unless you clearly define how and when you’re going to handle removing a standard or updating it to reflect better use cases.

Language designers admittedly should worry about constant breakage but it’s fine to have some churn, and we shouldn’t be so concerned of it that it freezes everything

Unfortunely C++ on the last set of revisions has gotten that sequence wrong, many ideas are now PDF implemented before showing up in any compiler years later.

Fully-thought-out and feature-complete is something that since C++17 has been hardly happening.

Since C++17 that anything hardly goes "through boost, folly, absl, clang, or GCC (or are vendor-specific features) before going to std.".

The issue is that it's sitting in nightly for years. Many many many years.

I don't write software targetting nightly, for good reason.