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Matt Godbolt sold me on Rust by showing me C++

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Re: Matt Godbolt sold me on Rust by showing me C++

#91

Post by tcfhgj »

kelnos wrote: post #67
zozbot234 wrote: post #40

Earlier quoted context omitted.

> The one thing that sold me on Rust (going from C++) was that there is a single way errors are propagated: the Result type. No need to bother with exceptions This isn't really true since Rust has panics. It would be nice to have out-of-the-box support for a "no panics" subset of Rust, which would also make it easier to properly support linear (no auto-drop) types.

I wish more people (and crate authors) would treat panic!() as it really should be treated: only for absolutely unrecoverable errors that indicate that some sort of state is corrupted and that continuing wouldn't be safe from a data- or program-integrity perspective. Even then, though, I do see a need to catch panics in some situations: if I'm writing some sort of API or web service, and there's some inconsistency in…

would you consider panics acceptable when you think it cannot panic in practice? e.g. unwraping/expecting a value for a key in a map when you inserted that value before and know it hasn't been removed?

you could have a panic though, if you wrongly make assumptions

Re: Matt Godbolt sold me on Rust by showing me C++

#92

Post by Etheryte »

kasajian wrote: post #84

This seems a big silly. This is not a language issue. You can have a C++ library that does exactly all the things being shown here so that the application developer doesn't worry about. There would no C++ language features missing that would accomplish what you're able to do on the Rust side. So is this really a language comparison, or what libraries are available for each language platform? If the latter, that's fin…

Just like language shapes the way we think and talk about things, programming languages shape both what libraries are written and how. You could write anything in anything so long as it's Turing complete, but in real life we see clearly that certain design decisions at the language level either advantage or disadvantage certain types of solutions. Everyone could in theory write C without any memory issues, but we all know how that turns out in practice. The language matters.

Re: Matt Godbolt sold me on Rust by showing me C++

#93

Post by jpc0 »

ModernMech wrote: post #33

What sold me on Rust is that I'm a very bad programmer and I make a lot of mistakes. Given C++, I can't help but hold things wrong and shoot myself in the foot. My media C++ coding session is me writing code, getting a segfault immediately, and then spending time chasing down the reason for that happening, rinse and repeat. My median Rust coding session isn't much different, I also write code that doesn't work, but i…

Using your media example since I have a decent amount of experience there. Did you just use off the shelf libraries, because effectively all the libraries are written in or expose a C api. So now you not only need to deal with Rust, you need to also deal with rust ffi.

There are some places I won’t be excited to use rust, and media heavy code is one of those places…

Re: Matt Godbolt sold me on Rust by showing me C++

#94

Post by [deleted] »

jasonjmcghee wrote: post #12
dvratil wrote: post #8

The one thing that sold me on Rust (going from C++) was that there is a single way errors are propagated: the Result type. No need to bother with exceptions, functions returning bool, functions returning 0 on success, functions returning 0 on error, functions returning -1 on error, functions returning negative errno on error, functions taking optional pointer to bool to indicate error (optionally), functions taking r…

unfortunately it's not so simple. that's the convention. depending on the library you're using it might be a special type of Error, or special type of Result, something needs to be transformed, `?` might not work in that case (unless you transform/map it), etc. I like rust, but its not as clean in practice, as you describe

[deleted]

Re: Matt Godbolt sold me on Rust by showing me C++

#95

Post by jpc0 »

sunshowers wrote: post #29
atemerev wrote: post #28

Right. I attempted using Rust for trading-related code as well. However, I failed to write a dynamically linked always sorted order book where you can splice orders in the middle. It is just too dynamic for Rust. Borrow checker killed me. And don't get me started on dynamic graphs. I would happily use Rust over C++ if it had all other improvements but similar memory management. I am completely unproductive with Rust…

I apologize for the naive question, but that sounds like a heap?

In my experience you need to approach this with vec or arrays of some sort and pass indices around… “We have pointers at home” behaviour. This is fine but coming from C++ it definitely feels weird…

Re: Matt Godbolt sold me on Rust by showing me C++

#97

Post by lytedev »

kasajian wrote: post #84

This seems a big silly. This is not a language issue. You can have a C++ library that does exactly all the things being shown here so that the application developer doesn't worry about. There would no C++ language features missing that would accomplish what you're able to do on the Rust side. So is this really a language comparison, or what libraries are available for each language platform? If the latter, that's fin…

The core of this argument taken to its extreme kind of makes the whole discussion pointless, right? All the languages can do all the things, so why bother differentiating them?

To entertain the argument, though, it may not be a language issue, but it certainly is a selling point for the language (which to me indicates a "language issue") to me if the language takes care of this "library" (or good defaults as I might call them) for you with no additional effort -- including tight compiler and tooling integration. That's not to say Rust always has good defaults, but I think the author's point is that if you compare them apples-to-oranges, it does highlight the different focuses and feature sets.

I'm not a C++ expert by any stretch, so it's certainly a possibility that such a library exists that makes Rust's type system obsolete in this discussion around correctness, but I'm not aware of it. And I would be incredibly surprised if it held its ground in comparison to Rust in every respect!

Re: Matt Godbolt sold me on Rust by showing me C++

#98

Post by sdenton4 »

kasajian wrote: post #84

This seems a big silly. This is not a language issue. You can have a C++ library that does exactly all the things being shown here so that the application developer doesn't worry about. There would no C++ language features missing that would accomplish what you're able to do on the Rust side. So is this really a language comparison, or what libraries are available for each language platform? If the latter, that's fin…

If the default is a loaded gun pointed at your foot, you're going to end up with lots of people missing a foot. "just git gud" isn't a solution.

Re: Matt Godbolt sold me on Rust by showing me C++

#99

Post by bigstrat2003 »

jpc0 wrote: post #95
sunshowers wrote: post #29

Earlier quoted context omitted.

I apologize for the naive question, but that sounds like a heap?

In my experience you need to approach this with vec or arrays of some sort and pass indices around… “We have pointers at home” behaviour. This is fine but coming from C++ it definitely feels weird…

Why not just use pointers? Rust has them, they aren't evil or anything. If you need to make a data structure that isn't feasible with references due to the borrow checker (such as a linked list), there's absolutely nothing wrong with using pointers.

Re: Matt Godbolt sold me on Rust by showing me C++

#100

Post by [deleted] »

jasonjmcghee wrote: post #12
dvratil wrote: post #8

The one thing that sold me on Rust (going from C++) was that there is a single way errors are propagated: the Result type. No need to bother with exceptions, functions returning bool, functions returning 0 on success, functions returning 0 on error, functions returning -1 on error, functions returning negative errno on error, functions taking optional pointer to bool to indicate error (optionally), functions taking r…

unfortunately it's not so simple. that's the convention. depending on the library you're using it might be a special type of Error, or special type of Result, something needs to be transformed, `?` might not work in that case (unless you transform/map it), etc. I like rust, but its not as clean in practice, as you describe

[deleted]
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