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What is Rust and why is it so popular?

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Re: What is Rust and why is it so popular?

#101

Post by mcqueenjordan »

pron wrote: post #39
ChrisSD wrote: post #4

I think one of the biggest benefits of Rust is it bakes in static analysis of code as a first class feature. Which means the language is amenable to analysis and you don't have to use third party tools to benefit from it. I also like some of the abstractions. They're clever in their simplicity. For example, an iterator over an array or vector is simply doing a for loop using pointers.

Yes and no. It provides some kinds of (important!) static analysis out of the box, but at the cost of complexity, which directly adversely affects some other kinds of (also important) static analysis. For example, there are sound static analysis tools that guarantee no undefined behavior of C code, but AFAIK, such tools can at best only work on a subset of C++, because of its complexity. Rust goes all out on eliminat…

What is the complexity, and what are its costs? As an active user of Rust, I haven't seen the (adverse) complexity or its costs yet.

It's worth pointing out that Rust combats more than undefined behavior. Undefined behavior is a category of bad things that Rust works to eliminate, but Ownership goes beyond eliminating UB, and eliminates a large swath of potential logic bugs.

Re: What is Rust and why is it so popular?

#102

Post by derefr »

Const-me wrote: post #96
derefr wrote: post #84

Earlier quoted context omitted.

> This affects how easy it is to write custom compilers (very important in the embedded space) Is there a reason you’d write your own Rust compiler frontend , rather than just letting rustc generate LLVM IR as it does, and then writing your own LLVM arch target? None of the Rust complexity leaks over into the LLVM IR it generates; it looks just like the LLVM IR that e.g. clang generates.

> None of the Rust complexity leaks over into the LLVM IR it generates The leakage even triggers performance issues in compilers: https://users.rust-lang.org/t/5-hours-to-compile-macro-what-...

No, that's not "Rust leakage", because that misbehavior has nothing to do with the semantics of Rust as a language. That's the effect of some non-optimized function-scope-level pattern-matching substitutions that LLVM is applying, as applied to the user's very large function body. Quoting a reply in that same thread:

> LLVM is not good at big functions, I have seen this before as well. One of the functions you are generating is almost 100,000 lines of Rust code including tons of internal control flow.

The same would happen if you wrote (or generated) 100,000 lines of C in one function body, and fed it through Clang with -O2.

If you're wondering, there's nothing in rustc that makes it implicitly turn regular code into huge function bodies, either. It's just someone abusing Rust macros to codegen badly, not taking into account how the granularity of units of compilation interacts with the time-complexity of optimization passes.

Re: What is Rust and why is it so popular?

#103

Post by psv1 »

Because the StackOverflow survey which Rust keeps winning defines "Most Loved" as:

> % of developers who are developing with the language or technology and have expressed interest in continuing to develop with it

Because there aren't that many Rust jobs, almost no one has to use it. Which means people either try it and leave, they like the language and stick around, or they never use it (the overwhelming majority of developers). This leads to the Rust being the most loved language by the above definition, which is completely different from "popular" (as in the title of the OP).

If I make up my own language that I plan to never stop using, even if no one else ever touches it, I'll get 100% "Most Loved" on StackOverflow's survey.

Re: What is Rust and why is it so popular?

#104

Post by orclev »

pron wrote: post #80
DCKing wrote: post #74

Earlier quoted context omitted.

As someone who never much got into systems programming, Rust feels like a breath of fresh air. It makes systems programming way more accessible for me personally, coming from non-systems languages. Learning to write C well is just not something that appeals to me at all. From mostly an outsiders' perspective, I just don't think C is a very nice programming language. It looks easy to to pick up and it probably is (for…

> As someone who never much got into systems programming, Rust is a breath of fresh air. I think that's part of the problem :) Because Rust looks high level it appeals to people used to high-level programming. But once you get into systems programming, the issues are different from high-level programming, and you're less happy to pay for features that solve other problems. What I'm saying is, obviously, a matter of t…

Part of the problem is that "systems programming" is an overloaded term that means a number of different things. Is writing a web browser "systems programming"? What about a CLI utility like grep? Kernel module? Bare metal on a STM32? Depending on who you ask most of those will get both a yes and a no answer. On a related note, some language are more or less suitable for each of those. Can you write an OS in Java? Yes. Should you? Probably not.

I think one of the previous comments, and others on other forums have things right when they say that Rust is a better C++. Anything you would consider using C++ for is a good candidate for using Rust for. Rust is not a better C though, it's just a bit too high level for that. There are languages that are aiming to be a better C (Zig is REALLY interesting, but very very new right now), but Rust isn't really one of them.

I could very easily see something like an OS aimed at x86 desktops being written in Rust. Desktop systems are beefy enough and the problem space is complex enough that the extra overhead involved in Rust (similar to C++) makes sense. On the other hand if you're doing some bare metal work on something like an Arduino you just don't have enough there to justify the extra overhead and something very basic like C (or assembly, or Zig once it matures a bit more) is probably a better fit.

If you're doing anything higher level than kernel programming, Rust is just as viable as anything else, at that point it's mostly down to personal preference on whether you can deal with not having conveniences like garbage collection or not.

Re: What is Rust and why is it so popular?

#105

Post by galangalalgol »

steveklabnik wrote: post #29
jdlyga wrote: post #14

Rust using the LLVM toolchain is a real plus, which Clang also uses in the C++ world. The Clang and Rust compilers are basically frontends to LLVM, and any language that compiles using LLVM is translated to IR (intermediate representation). All code optimization is done on the IR code itself in LLVM, which both Rust and C++ compile down to before being compiled further into assembly. That means that the same effort t…

We have started doing our own optimizations too: https://blog.rust-lang.org/inside-rust/2019/12/02/const-prop... Your overall point is absolutely correct though. We couldn’t have done this without LLVM.

Can you comment on the current state of non-aliased related optimizations? The issue tracker is byzantine on that one and i can't tell if or to what degree those optimizations are now done.

Re: What is Rust and why is it so popular?

#106

Post by GolDDranks »

rb808 wrote: post #12
zozbot234 wrote: post #9

The more pressing question: What is Rust and why is it so popular on HN?

I did an internet search for Rust jobs and it was near-zero. Would be nice but reality calls.

Rust is over the "100% hobbyist" phase, but it isn't still in the phase where you hire "Rust developers" verbatim. There's an important phase in between: Rust is being introduced in organizations as we speak, and some people that were originally hired for some other skills, develop in Rust they picked up because they were enthusiastic about it.

I am in that position at the moment. We are a multi-language shop, and there's some components that make sense to write in Rust.

Re: What is Rust and why is it so popular?

#107

Post by ggregoire »

MadWombat wrote: post #52
alerighi wrote: post #18

Rust is a great language if you use for what was intended, system programming and as safe substitute of C and C++. But it's not the answer of everything, to me it's nowadays abused in a lot of projects, there are instances of project where using Rust not only doesn't make a lot of sense but also can be slower than another languages, there are cases where Go is better, other where Node.js is better, other where Python…

OK, I will bite. If I had to come up with a case where Python is better than Rust, I would say with rapid prototyping and scientific computing. If you just want to try a few things out, python has faster development cycle and if you want to do some super clever math python has better library support. With a bit more mind stretching, I can make a case for Go with a bit more mind stretching. If you want to write a mass…

> If I had to come up with a case where Python is better than Rust, I would say with rapid prototyping and scientific computing.

Scripting? I'm not gonna write a 50 LOC single-use script in Rust.

Re: What is Rust and why is it so popular?

#108

Post by SAI_Peregrinus »

jdlyga wrote: post #14

Rust using the LLVM toolchain is a real plus, which Clang also uses in the C++ world. The Clang and Rust compilers are basically frontends to LLVM, and any language that compiles using LLVM is translated to IR (intermediate representation). All code optimization is done on the IR code itself in LLVM, which both Rust and C++ compile down to before being compiled further into assembly. That means that the same effort t…

The other nice part of using LLVM is that you don't have to write a new Rust compiler for a new target, you just need to write the LLVM backend to convert LLVM IR to the target's assembly. That's substantially easier to do. So while LLVM doesn't support as many architectures as GCC yet it's far easier to add new architectures to it.

Re: What is Rust and why is it so popular?

#109

Post by christiansakai »

MadWombat wrote: post #52
alerighi wrote: post #18

Rust is a great language if you use for what was intended, system programming and as safe substitute of C and C++. But it's not the answer of everything, to me it's nowadays abused in a lot of projects, there are instances of project where using Rust not only doesn't make a lot of sense but also can be slower than another languages, there are cases where Go is better, other where Node.js is better, other where Python…

OK, I will bite. If I had to come up with a case where Python is better than Rust, I would say with rapid prototyping and scientific computing. If you just want to try a few things out, python has faster development cycle and if you want to do some super clever math python has better library support. With a bit more mind stretching, I can make a case for Go with a bit more mind stretching. If you want to write a mass…

For massively parallel even with async, I still think Go is better than NodeJS. I still don't know how to do bounded parallelism in NodeJS but really easy in Go.

Re: What is Rust and why is it so popular?

#110

Post by pornel »

jokoon wrote: post #68

This language is awesome, but I'm quite conservative when it comes to syntax. I don't like how Rust is trying to move away from C when considering syntax. I tend to prefer languages that can adopt the "C flavor". Python, in my view, does this very well: its syntax is simple, because it borrows a lot from C in its "flavor". Rust is not doing that, and that's a hurdle. In my view, the "C flavor" is very important becau…

Rust has quite C-like syntax IMHO, with a few important fixes. Types are easier to write and don't have typedef parsing gotcha. Array of 10 functions returning functions in Rust is `[fn() -> fn(); 10]`. I'd faint trying to write such type in C.

    if (foo) bar();
is

    if foo {bar();}
Same length, but without possibility of "goto fail" error.

Rust may look ugly, especially with generics, but on the technical level there isn't much wrong with the syntax. It's quite readable once you know it. And you can grep function definitions!

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