I realize /r/rust (Reddit) isn't representative of the entire Rust community but it's given me a really bad impression of Rust culture.
What is Rust and why is it so popular?
161–170 of 284 posts
Re: What is Rust and why is it so popular?
#162Earlier quoted context omitted.
People write code generators that emit C/C++ code all the time, and 10KLOC functions coming from such a generator isn't unheard of. The x86 instruction selector LLVM generates from tablegen is over 240KLOC, although that's emitted effectively as an interpreted table, so the actual code size of the function is much, much smaller.
You’re correct that it’s possible to trigger that performance issue without Rust. However, it doesn’t happen with idiomatic C or C++ code. C macros are too hard to use for that. C++ templates are designed to expand into many small functions, as opposed to a single huge one. It was Rust complexity leaking over into the LLVM IR.
At the scale of macro complexity that occurred in the Rust code, you would be dealing with autogenerated C/C++ code. Autogenerated C/C++ code of that complexity absolutely exists in practice.
The problem here isn't Rust's complexity; it's autogeneration taken to the extremes without concern for its impact on compile time. The fact that Rust provides builtin macro syntax to do this autogeneration is of little importance, since it will happen just as frequently with external build tools in the C/C++ world.
Re: What is Rust and why is it so popular?
#163Earlier quoted context omitted.
In my experience, the vast majority are exactly like the error they show. Some are even better. I haven't hit a warning in ages that hasn't been able to be auto fixed by `cargo fix`. However not all of them are. Back in the pre-async/await days you'd end up with some really gnarly implicit types in some really big functions with lots of returns. Then sometimes you'd make a mistake on one of the returns and the compil…
Thanks for the kind words. I would say that subpar errors fall in one of two camps: incredibly uncommon (so we haven't "exercised" that muscle to clean them up) or incredibly hard to deal with. I monitor the issue tracker so if you do encounter a confusing error, file a ticket, we treat them seriously.
Thank you for your hard work on rust. The intelligent error messages are a significant part of what makes rust such a joy to use.
And will do, if I encounter them.
Re: What is Rust and why is it so popular?
#164Earlier quoted context omitted.
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? Ye…
> If you're doing anything higher level than kernel programming, Rust is just as viable as anything else I don't think so because it suffers from the same limitation that all low-level languages have, which is that API clients need to be aware of implementation details. Rust sometimes makes that propagation of leaked information automatically via the type system, but internal implementation details -- how allocated m…
That's not a limitation of "low-level languages", it's inherent in low-level API's. These two are not the same. You could have a Rust program that interfaces with outside systems only via protobufs over a network socket, or what have you, and it will work just fine. Same for just about any "high-level API" format you could think of. Of course, using such high-level formats comes at an efficiency cost since you have to translate along the way. But other languages are the same, they just hide that step from you.
Re: What is Rust and why is it so popular?
#165I work in the embedded space, but the majority of my work is writing simuators, mathematical models and tests. One of the hidden benefits for us was that rust is suitable for both resource-constrained embedded code (we use a lot of C for this) and high-level desktop and cloud based infrastructure/sim/test code, which we would never consider writing in C. Serde is amazing, crates.io has so much good stuff on it, C int…
Now switch to Julia instead of Python/matlab and you have a really solid stack.
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Re: What is Rust and why is it so popular?
#166Earlier quoted context omitted.
People write code generators that emit C/C++ code all the time, and 10KLOC functions coming from such a generator isn't unheard of. The x86 instruction selector LLVM generates from tablegen is over 240KLOC, although that's emitted effectively as an interpreted table, so the actual code size of the function is much, much smaller.
You’re correct that it’s possible to trigger that performance issue without Rust. However, it doesn’t happen with idiomatic C or C++ code. C macros are too hard to use for that. C++ templates are designed to expand into many small functions, as opposed to a single huge one. It was Rust complexity leaking over into the LLVM IR.
> C++ templates are designed to expand into many small functions, as opposed to a single huge one.
...so are Rust macros. The user was using Rust macros very non-idiomatically.
Also, you don't use C macros to write (large amounts of) C. 90% of the world's generated C, by volume, comes from, I would say, one of two programs: autoconf (through m4), or yacc. And both autoconf check stanzas and yacc's inline C support are easy to screw up in ways that result in horrible code that makes compilers barf.
Also, to be clear, you're conflating two things with the phrase "Rust complexity." This thread was originally about the difficulty of implementing a Rust compiler for a toolchain, which therefore makes "Rust's complexity" here refer specifically to the complexity of the static-analysis semantics of Rust that make writing a Rust compiler frontend difficult.
The solution—relying on the existing rustc frontend for the "hard stuff", and just implementing your own compiler backend to target the embedded architecture—is not rebutted by a claim that you can write bad Rust code that makes the optimization passes of certain compilers choke. You wouldn't even be writing optimization passes. You'd be writing a backend. The optimization passes are universal. It's the job of the LLVM developers to ensure that they don't choke on things like this.
And, despite the fact that 100,000-line functions are dumb, it's the LLVM development team's fault that the optimization passes were written in such a way that their time-complexity is superlinear in a way that stalls out when optimizing a function like that. It's not up to the Rust compiler authors to not emit that type of code, or to somehow prevent you from writing it; it's up to the LLVM devs to make their optimizer work, and work efficiently, for any "valid" code. Honestly, if anything, this code—if you could get it—would be a great integration test to submit to LLVM, for them to work towards passing.
Re: What is Rust and why is it so popular?
#167Wow, that is an extremely well-written brief introduction to Rust. I love the way it manages to address some more technical (e.g. FFIs, distinction between borrow-checker and other parts of compiler) but important concepts despite being so short. Thanks very much Jake Goulding if you're reading.
You are quite welcome! Hope to see you writing some Rust sometime!
I have tried one project so far: https://github.com/dandavison/delta
Re: What is Rust and why is it so popular?
#168Earlier quoted context omitted.
The key is in another comment on this thread: > Lots of these things that look like syntax problems are in fact design problems surfaced by the compiler. A lot of people are finding value in the rules Rust provides. This is irrespective of domain. The strict compiler helps you refactor code in ways that less strict languages don't. You still can do it, of course, you just have a lot less help. The trick is, is the in…
I think this is misplaced causation. Don’t discount the fact that a significant number of programmers just like novelty and like Rust because it’s new in the same way Haskell is new to a Java dev. That said, Rust’s domain does seem wider than just systems programming. It has the right abstractions to be suitable for (edit: some ) higher level things like web apps. Personally Rust is turning into what I was assuming a…
sorry for the tangent, but what has Go turned into in your opinion? (I'd believe it fits quite well your definition)
Re: What is Rust and why is it so popular?
#169The more pressing question: What is Rust and why is it so popular on HN?
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Re: What is Rust and why is it so popular?
#170I like everything I see and read about rust but I'm unsure where I'd fit it into my work. Does rust have a future in areas like backend web development or mobile?
it's pretty great for non trivial CLIs. I was using it at my previous org for a tool to take JSON config files to generate a bunch of C++ boilerplate so we could rapidly prototype different ideas.