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Ask HN: What is the state of C++ vs. Rust?

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Re: Ask HN: What is the state of C++ vs. Rust?

#11

Post by carols10cents »

xjia wrote: post #7
rlnunes wrote: post #5

I have a big C++ legacy code, and it gives me a lot of headhaches. I'm using Rust in some small projects and it's great, no problens with null pointers :). I think a great feature of Rust is that it is easy to use inside C/C++ projects, so u can upgrade your current legacy code without rewrite it :)

Do you mean C/C++ and Rust interop? Maybe link them together to form the final executable binary? Can you share more experience on how do you do that?

Not the OP, but I did a talk on an incremental rewrite of a C library to Rust [1]. Rust has good FFI capabilities with C and other languages through that [2].

[1]- https://github.com/carols10cents/rust-out-your-c-talk

[2] - http://jakegoulding.com/rust-ffi-omnibus/

Re: Ask HN: What is the state of C++ vs. Rust?

#12

Post by seren »

bluejekyll wrote: post #8
seren wrote: post #2

Rust is promising but C++ is here to stay. If you have a legacy C++ code base, it is much easier to sell that you are just upgrading the compiler to get new language features, that you are rewriting everything from scratch. Now we'll have to see in the next few years if, for new projects, Rust is chosen over C++ wherever it was used traditionally and in which proportion.

Like all legacy code, it will not be replaced. Now if people wanted to bifurcate their codebase they can easily add Rust libraries to existing C++ codebases. In my experience I find Rust to be more productive than C++ and easier to write. Obviously that's a pure opinion.

I do agree with you, and I hope this is the future.

However, in big organizations, which are not exactly nimble, this is even hard to say, "Okay we've been developing in C++ for 20 years, now the next part of our infrastructure will be written in Rust".

This will be seen as an unwanted risk, associated with a training cost. You will have to demonstrate unequivocally Rust's advantage.

Re: Ask HN: What is the state of C++ vs. Rust?

#13

Post by JoshTriplett »

I find this comparison much easier than comparing C and Rust. C has an extensive and still unparalleled set of libraries available using the C calling conventions; both C++ and Rust can call those libraries but often want a translation layer that adapts to the conventions of the language. C++ and Rust both have extensive libraries of their own; while C++ has been around longer, you'll still often find yourself needing to use a C library because a native C++ library doesn't exist. (It doesn't help that C++ has gone through several ABI changes, and still doesn't reliably have a cross-compiler compatible ABI the way C does; even clang++ and g++ have had various incompatibilities, and still prefer separate C++ standard libraries. C remains the reliable ABI for libraries.)

While I'm impressed with the changes in modern C++11/14/17, it has both the feature and problem of still including classic C and C++. There's a reasonable subset of C++ to program in, but nobody can quite agree on what that is, and a codebase can't easily enforce that. And C++ is still a very large language, with quite a bit of surface area in the language itself; I prefer a smaller language with a large library ecosystem.

Rust is still quite young. It's incredibly fun to program in, has the most welcoming community I've ever seen, and can help you write safe, expressive, high-performance code. (Tip: check out the "rayon" crate for incredibly easy parallelism.) It has an extensive library ecosystem, and a robust FFI to call (or be called by) C code. However, depending on what you're doing and and how many boundaries you're pushing, you may find some corners of the language still under active development; for instance, if you want to embed some Rust code into a broader build system that builds various other components under other languages, support for that just went into Cargo.

If you're writing pure Rust code, or Rust code that calls out to C, you should find the language and ecosystem ready now. If you're trying to embed Rust into an existing project, expect to play with various experimental bits for a while.

Re: Ask HN: What is the state of C++ vs. Rust?

#14

Post by esrauch »

alexnewman wrote: post #9

They are both great languages but rust is clearly the one that experts in both generally prefer. I have some friends who make some strange arguments for c++ but I continue to be interested why people don't want to make the switch. That being said LEGACY

I would be careful about what you generalize from "experts in both generally prefer rust", as there is likely a survivor bias in there.

Since C++ has been around much longer the situation is likely "many C++ experts try Rust, the ones that love it become Rust experts", basically if "preferring Rust" ends up being a soft prerequisite to becoming a Rust expert then those who are experts in both will prefer Rust.

I also think there's a bunch of other factors that lead to a similar bias: general pride in favor of the less mainstream languages, for languages like Rust or Haskell it is probably the case that more of the code in that language is written by "hardcore" people, which means code written in that language is higher quality (but not necessarily through any intrinsic benefit of the language, instead through a selection of who is writing that language).

Re: Ask HN: What is the state of C++ vs. Rust?

#15

Post by mi100hael »

agentgt wrote: post #3

This is all personal opinion so take it with a grain of salt. I think Rust could do some serious C++ competition if it could dethrone C++ from some platform or have a worthy alternative. That is I think Rust really needs a killer app/platform/problem similar to how Swift has Apple devices and DevOps now have Go. If Rust could get into a gaming platform or have a really good gaming library like Unity it could have a g…

> Alternatively I think Rust could compete heavily with Go since the whole microservices space is still sort of up for grabs (or atleast is so massive that there is plenty of pie to be had).

I think you're wrong about this one. Go has a ton of HTTP libraries that make it dead simple to get a web service up and running with all the features you'd expect like pattern-matching URL routing, database backends, sessions, etc. Building something in Rust would be much more painful.

Re: Ask HN: What is the state of C++ vs. Rust?

#16

Post by vvanders »

Long time C++ dev here(~15 years) currently loving Rust. Someone can probably put together a more eloquent comment however here's my top marks.

1. No memory corruptions/null pointers. Legit holds up to the promises here.

2. The path of least resistance is single-ownership which is far and away the best way I've seen to structure C/C++ applications.

3. Cargo: Pure awesome. Simply one of the best dependency management/build tools I've used.

4. Dead simple x-platform support. Windows, Linux, all just works. Heck I just built an android arm-eabi target yesterday on windows with no NDK/etc.

5. Tagged unions, pattern matching. The best effing iterator class I've seen bar none. Once you've used these you don't want to go back.

6. Great built-in unit testing support(combines with Cargo above).

7. Amazing community, no ego and tons of people happy to help.

I still work regularly on C++0x11 codebases but any greenfield stuff I've moved over to Rust fulltime.

I still like C++ but it's so much more painful to use. Heck just earlier today I got bit by not compiling on OSX due to some obscure compiler differences that worked on MSVC and GCC. There's certainly good improvements coming to C++ but they have to support so much legacy code that I don't think they could ever make the large breaking changes that Rust has to produce a better experience.

Re: Ask HN: What is the state of C++ vs. Rust?

#17

Post by agentgt »

mi100hael wrote: post #15
agentgt wrote: post #3

This is all personal opinion so take it with a grain of salt. I think Rust could do some serious C++ competition if it could dethrone C++ from some platform or have a worthy alternative. That is I think Rust really needs a killer app/platform/problem similar to how Swift has Apple devices and DevOps now have Go. If Rust could get into a gaming platform or have a really good gaming library like Unity it could have a g…

> Alternatively I think Rust could compete heavily with Go since the whole microservices space is still sort of up for grabs (or atleast is so massive that there is plenty of pie to be had). I think you're wrong about this one. Go has a ton of HTTP libraries that make it dead simple to get a web service up and running with all the features you'd expect like pattern-matching URL routing, database backends, sessions, e…

There are libraries (I didn't downvote you but I suppose that is why as simple googling shows that) [1].

That being said one would argue if you are going the microservices route you shouldn't need an exceptional amount of routing anyway. You only need to really handle raw HTTP for the most part (also I would not say HTTP is the end all for microservices... I have been using a Rust AMQP library with some success [2]).

Also although Go has green threads it is still debatable if that is the right way or golden way particularly when so many backends like databases (e.g. postgres) can't handle async (tons of connections) anyway. Old school one thread per request libraries in Java like dropwizard can still do fairly well. I think Rust made the right choice with native threads and hopefully some interesting green thread or reactive libraries will come forth soon (or already here ... haven't googled it).

Also I'm just not sure I really buy into Go's channels but that is just a personal opinion at the moment.

[1]: https://youtu.be/pTQxHIzGqFI?t=964A

[2]: https://github.com/Antti/rust-amqp

Re: Ask HN: What is the state of C++ vs. Rust?

#18

Post by blub »

Wrong place to ask the question. HN has a high proportion of people with an unusual interest in trying out programming languages and I would say the average visitor doesn't particularly like C++.

From my point of view, Rust doesn't offer any benefits that would justify a switch. I would lose a lot of experience, libraries, a mature stable platform and job opportunities in exchange for more memory safety - something that's not a particularly pressing issue for me.

Furthermore, I think many developers obsess about languages and keep searching for a perfect language that doesn't exist and even if it did wouldn't have a big impact on productivity and the business anyway. The major challenges in organisations are of a social or process nature.

They're also biased in a surprising way by social factors such as who created a PL or the community. Meanwhile PHP, Java, C++ and C# and C make the world go round.

Key questions for me when evaluating whether to learn Rust (or any language):

* can I get a good job programming in this? Without moving to another country or continent.

* is my industry showing interest in it?

* is any industry showing interest?

The answer to all these questions seems to be "no".

Re: Ask HN: What is the state of C++ vs. Rust?

#19

Post by peterhj »

Rust has been pretty critical to me for getting my work up and running with minimal debugging (I'm in CS grad school, working on deep learning and optimization). I'm super productive programming in Rust, which is also generally a pleasure to write in.

Just last week I had to land a pretty major refactoring (swapping out a single wrapper type for a differentiable "operator" with an implicit operator graph instead). It basically just worked out of the box as soon as I got it to compile. Definitely something to be said for working _with_ the compiler and its messages on moving, borrowing, mutability etc. (Incidentally, if I had to program exclusively in C++11/14, thanks to Rust I'd have become much better at programming in C++.)

Re: Ask HN: What is the state of C++ vs. Rust?

#20

Post by thecity2 »

peterhj wrote: post #19

Rust has been pretty critical to me for getting my work up and running with minimal debugging (I'm in CS grad school, working on deep learning and optimization). I'm super productive programming in Rust, which is also generally a pleasure to write in. Just last week I had to land a pretty major refactoring (swapping out a single wrapper type for a differentiable "operator" with an implicit operator graph instead). It…

Curious since you say you work on deep learning/optimization. I'm a data scientist who does most everything in Python, but I've been interested in learning Rust. What is the state of "data science" toolkit for Rust at this point? For reference, I regularly use sklearn, Pandas, and Spark and would be looking for similar tools.
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