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How I went about learning Rust

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Re: How I went about learning Rust

#151

Post by dannymi »

nailer wrote: post #131
davidatbu wrote: post #102

Earlier quoted context omitted.

The Billion Dollar Mistake refers to the fact that things that are not explicitly marked as "nullable" can be null/nil. In rust, you would annotate score as `Option ` (`u32` is one of Rust's integer types), and then you would set the score of someone who hasn't sat the test yet as `None`, and someone who got a 100 on the test as `Some(100)`.

Oh yeah, allowing values to be nullable by default is bad, that's totally different than just 'including null'. I thought they meant including null in the language! > you would set the score of someone who hasn't sat the test yet as `None` Yep that's what I expected. Emoji thumbs up.

>Oh yeah, allowing values to be nullable by default is bad, that's totally different than just 'including null'.

In Rust (and Haskell and OCaml for that matter), there is no built-in null keyword. Option is just an enum in the library that happens to have a variant called None. So it's technically Option::None and Option::Some(x). But, really, it could be Quux and Quux::Bla and Quux::Boo(x) instead--without any language changes.

That is vastly better that what IntelliJ does for Java with their weird @NonNull annotations on references--which technically still can be the null. null is still a keyword there, and null is somehow a member of every reference type (but not of the other types--how arbitrary).

And C# has a null keyword, and the rules for type autoconverting it are complicated, and some things you just aren't allowed to do with null (even though they should be possible according to the rules) because then you'd see what mess they made there (you'd otherwise be able to figure out what the type of null is--and there's no "the" type there. null is basically still a member of every type. And that is bad).

So even the language used in "allowing values to be nullable by default" is insinuating a bad idea. Nullability is not necessarily a property that needs to exist on values in the first place (as far as the programming language is concerned).

Re: How I went about learning Rust

#152

Post by abiro »

zozbot234 wrote: post #42
Animats wrote: post #39

Earlier quoted context omitted.

Yes. Rust is for what you'd otherwise have to write in C++. It's overkill for web services. You have to obsess over who owns what. The compiler will catch memory safety errors, but you still have to resolve them. It's quite possible to paint yourself into a corner and have to go back and redesign something. On the other hand, if you really need to coordinate many CPUs in a complicated way, Rust has decent facilities…

> You have to obsess over who owns what. Most of the time you can also avoid this by just copying data using .clone(). This adds a tiny bit of overhead, which is why it isn't a default - but it'll still be comparatively very efficient. Similarly, there are facilities for shared mutation (Cell/RefCell) and for multiple owners extending the lifetime of a single piece of data (Rc/Arc). It's not that hard to assess where…

This big time. Rust has comparable ergonomics to high level languages once you stop trying to optimize everything and start throwing around clones liberally. And the nice thing is that if you do need to optimize something later you can trust the compiler that if it compiles, then it’s correct (barring interior mutability/unsafe).

Re: How I went about learning Rust

#153

Post by spicysugar »

xEnOnn wrote: post #3

I have been thinking to myself whether I should pick up Go or Rust as a new language this year. Coming from a NodeJS background, Rust looks a tad more complicated but it looks cooler. There are also more job listings looking for Golang than Rust which makes me wonder if Golang might be a more rewarding investment? What would be a good use case of Rust than Golang cannot do given its extra complexity and potentially l…

I personally feel rust is advertised more as safer and faster rather than as a practical yet harder alternative to C or C++. Although Go as a systems programming language is misleading, it's not something that is as heavily discussed about.

In the long run Rust's complexity will hurt newcomers(new to programming) while it will be a blessing for seasoned c and c++ devs. If all programming languages were tools, rust would be a very very specific tool which makes a lot of sense for a specific case. If nodejs and golang are tools, choosing one over another is easier as you can do same things in both easily with small effort. But you cannot rewrite all rust programs in nodejs or golang.

Finally you need to ask if rust is really worth picking over golang/nodejs for things that can be easily done in nodejs/golang. Rust is not for people who think is rust for them.

Arguments like some implementations are more elegant in some other language can always be brought up as arguments. They should only be taken into account when you run out of options to compare because they are exaggerated and subjective most of the times. For example(exaggerated) screaming why go doesn't have a borrower checker like rust makes no sense because go is garbage collected. For many people seeing such absence of features equate to lack of features in a programming language leading to more boilerplate or other downsides which is not necessarily true.

Re: How I went about learning Rust

#154

Post by mindri0t »

vimwizard wrote: post #44
davidatbu wrote: post #19

I just want to give a shout out to "Rust for Rustaceans". I'm only three chapters in, and it's definitely the most enjoyable technical reading I've ever done because you learn so much, so quickly, and so easily. Steve Klabnik (co-author of "The Rust Programming Language") says it's the book to read after going through "The Rust Programming Language", and I couldn't agree more.

The author fairly regularly live streams on youtube doing more advanced Rust programming, and is responsive to questions coming in.

To build on this, his Crust of Rust series videos are excellent deep dives targeted at the same stage of learning as the book.

Re: How I went about learning Rust

#155

Post by [deleted] »

Ygg2 wrote: post #114
hu3 wrote: post #49

Earlier quoted context omitted.

Comments like this one below are often downvoted without reply just because they criticise rust: > I founf myself in your same situation a few months ago. I chose Rust and regret it... https://news.ycombinator.com/item?id=32105336 GP puts it well: > Just like in any sect. As long as you agree everything is perfect, the community is the friendliest indeed. The community isn't toxic as long as you happen to agree with…

GP is also wrong. At this point it's mostly a meme. Rust is slow to compile. I mean, yeah if you abuse meta programming or monomorphisation. I've been programming in it, and while I like the language, I'm not on the language community bandwagon. E.g. CoC and it's enforcement (I think it's just pointless grandstanding).

[deleted]

Re: How I went about learning Rust

#156

Post by brobinson »

nailer wrote: post #149
brobinson wrote: post #106

Earlier quoted context omitted.

Read about sum types. They exist in Haskell, Rust, OCaml, Typescript, Swift, Kotlin, etc. You are likely only familiar with product types without knowing they're called product types. (Cartesian product) You can have 100% type-safe, guaranteed at compile time code without null that can still represent the absence of data. Once you've used sum types, you feel clumsy when using Javascript, Python, Go, Ruby, C, C++, etc…

https://old.lispcast.com/what-are-product-and-sum-types/ That was easy to understand. > You can have 100% type-safe, guaranteed at compile time code without null that can still represent the absence of data. If it's a single score, I'd still want to use null / int. There no invalid states being represented, anything else is still unnecessary complexity. > Nullness infects your data model and always comes out of nowhe…

>If it's a single score, I'd still want to use null / int.

In your example, you still have to manually check if there's a value every time, but this is not compiler-enforced. Should you forget, you will get a runtime crash at some point (likely in production at a critical time) with some kind of arithmetic error. This wouldn't be possible with a simple sum type.

Also, a sum type with units of Score(Int) and NoScore won't allow assignments of any other "null" instances. Null in one spot is interchangeable with null in any other spot, and this can lead to bugs and runtime crashes. Null should be avoided when possible.

Re: How I went about learning Rust

#157

Post by [deleted] »

hyperman1 wrote: post #87
zozbot234 wrote: post #76

Earlier quoted context omitted.

Rust actually supports most OOP features, with the main exception of implementation inheritance. And implementation inheritance is a nasty footgun in large-scale software systems (search around for: "fragile base class problem"), in a way that just doesn't apply to simple composition and pure interfaces (traits). So it's hard to fault Rust for including the latter and not the former.

For me it was the web-of-pointers strategy I had to unlearn. A child object keeping a pointer to its parent is misery in Rust. It forces you to either make the child completely independent or really prove the parent will be around until the child disappears. 90% of the time this is dumb overhead, but 10% of the time it found a bug in some edge case, so I learned to appreciate it as a tough teacher, and my designs got…

[deleted]

Re: How I went about learning Rust

#158

Post by Ygg2 »

pjmlp wrote: post #147
Ygg2 wrote: post #103

Earlier quoted context omitted.

Does it? I've seen it being repeated ad nauseam without any concrete backing. I mean it has some OOP concepts. But it's mostly in traits. Saying Rust is OOP is a bit like saying Chimera is a Goat. Anyone that tried to use OOP in Rust, knows it's next to impossible.

Yes it does, OOP is a spectrum not "like Java does it".

I'd consider something OOP if it has the same expressive power i.e. things expressible in OOP languages are easily expressible in another OOP language as well. And for Rust that's not the case.

Otherwise you end up with Haskell is an OOP language.

Re: How I went about learning Rust

#159

Post by kouteiheika »

gg2222 wrote: post #128
kouteiheika wrote: post #107

Earlier quoted context omitted.

> Anything where low-level control is required. It's not clear if there are true-Rust web apps in the wild (as opposed to web apps with some services in Rust); as far as I read, Rust web programming is ugly. There are. I run one. Written in pure Rust. 160k lines of Rust code in total, serving over 3 million HTTP requests per month. Best choice I've ever made. Rust especially shines when you need to maintain a big pro…

What Rust web libraries/frameworks do you use and recommend? How long does your Rust project take to compile?

> What Rust web libraries/frameworks do you use and recommend?

This might not be a satisfying answer for you, but I use my own framework. Its main selling point is that it can be compiled in two modes: during development it has zero dependencies and is blazingly fast to compile (it has its own minimal HTTP implementation, its own minimal executor, etc.), and for production it switches to use production-ready crates which everyone else uses (`hyper`, `tokio`, etc.)

Personally I'm not a fan of most frameworks which are commonly used in Rust webdev. The reason for that is twofold:

1) Most of them suffer from what I call the npm-syndrome, with hundreds of dependencies out of the box. Case in point, the minimal example from Warp's readme pulls in 146 crates.

2) They're often really complicated and have a lot of magic. I prefer simple functions with explicit control flow instead of layers upon layers of generics and macros stacked upon each other.

(DISCLAIMER: The following is purely my personal opinion; I'm not saying one approach is objectively better than the other, just stating what I prefer.)

For example, in Warp the way you add compression is by stacking a filter on top of your route:

    let examples = warp::path("ex")
        .and(warp::fs::dir("./examples/"))
        .with(warp::compression::deflate());
In my framework you have an explicit function through which every request goes through, so if want to add compression you just call a function which takes a request and returns it:

    fn deflate(response: Response) -> Response { ... }

    async fn server_main(request: Request) -> Response {
        let response = ...;
        let response = deflate(response);
        //
        return response;
    }
There's no magic and you can clearly see exactly what's going on, and you can also easily add new transformations without the need to become a trait astronaut.

Re: How I went about learning Rust

#160

Post by greenmana »

risyachka wrote: post #127
xEnOnn wrote: post #3

I have been thinking to myself whether I should pick up Go or Rust as a new language this year. Coming from a NodeJS background, Rust looks a tad more complicated but it looks cooler. There are also more job listings looking for Golang than Rust which makes me wonder if Golang might be a more rewarding investment? What would be a good use case of Rust than Golang cannot do given its extra complexity and potentially l…

For probably 99% of cases, Go will be a better fit as it is noticeably easier to learn and will require less time to do the task. Unless you need those extra nanoseconds of performance or super low-level features, Go will be a much better choice. In the end, they are just tools, and you need to choose them based on your needs, not language features.

I'd say it's also a question of team size and organization. Are you a singular developer, or in a large team, writing enterprise software that should be easy to pick up for someone reading the code 10 years later etc.
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