Comment by iagooar

6 months ago

Rust has been such a "pain" to learn - at least compared to other, more straight-forward languages. But boy does it feel good when you know that after a few back and forths with the compiler, the code compiles and you know, there is not much that is going to go wrong anymore.

Of course, I am exaggerating a bit - and I am not even that experienced with Rust.

But after coding with Ruby, JS/TS and Python - it feels refreshing to know that as long as your code compiles, it probably is 80-90% there.

And it is fast, too.

That’s my favorite feature. Rust turns runtime errors into compile time errors.

All that fighting with the compiler is just fixing runtime bugs you didn’t realize were there.

  • Rust is the most defect-free language I have ever used.

    I'd wager my production Rust code has 100x fewer errors than comparable Javascript, Python, or even Java code.

    The way Result<T,E>, Option<T>, match, if let, `?`, and the rest of the error handling and type system operate, it's very difficult to write incorrect code.

    The language's design objective was to make it hard to write bugs. I'd say it succeeded with flying colors.

    • Now try an actual functional programming language. I like Rust too but those features all come from FP, and FP languages have even more features like that that Rust doesn't yet or can't have.

> Rust has been such a "pain" to learn - at least compared to other, more straight-forward languages. But boy does it feel good when you know that after a few back and forths with the compiler, the code compiles and you know, there is not much that is going to go wrong anymore.

I found that at some point, the rust way kinda took over in my head, and I stopped fighting with the compiler and started working with the compiler.

I'm interested in what scenarios you don't get this same feeling when writing TS code? I of course agree with Ruby, JS, and Python.

  • One big source of bugs in TS is structural sharing. Like, imagine you have some complex object that needs to be accessed from multiple places. The obvious, high performance way to share that object is to just pass around references wherever you need them. But this is dangerous. It’s easy to later forget that the object is shared, and mutate it in one place without considering the implications for other parts of your code.

    I’ve made this mistake in TS more times than I’d like to admit. It gives rise to some bugs that are very tricky to track down. The obvious ways to avoid this bug are by making everything deeply immutable. Or by cloning instead of sharing. Both of these options aren’t well supported by the language. And they can both be very expensive from a performance pov. I don’t want to pay that cost when it’s not necessary.

    Typescript is pretty good. But it’s very normal for a TS program to type check but still contain bugs. In my experience, far fewer bugs slip past the rust compiler.

    • Appreciate it, that makes a lot of sense. I feel like I've been trained to favor immutability so much in every language that I sometimes forget about these things.

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  • Not parent comment, but TS is generally safe if you have types correct at system borders, but very scary when you don't. Some of the most impactful bugs I've seen are because a type for an HTTP call did not match the structure of real data.

    Also, many built in functions do not have sufficient typesafey like Object.entries() for instance

    • That is an issue with how TS works, but it can be significantly improved upon by using a library to verify the structure of deserialized data. zod is one example, or you could use protobufs. Fundamentally, this is an issue with any programming language. But having your base "struct"-like type be a hashmap leads to more mistakes as it will accept any keys and any values.

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    • I don't know Rust, and I'm genuinely curious: How does it improve over that problem?

      When you call a REST API (or SQL query for that matter), how does it ensure that the data coming back matches the types?

      TS allows you to do parse the JSON, cast it into your target type, done (hiding correctness bugs, unless using runtime verification of the object shape, see sibling comment). Does Rust enforce this?

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  • Typescript doesn't even support notions like "unsigned integer". It is not a serious attempt at type-safety; its main claim to fame is "better than raw Javascript" which is not saying much.

    • If you need to run in a JS environment it’s a hell of a lot. It’s a FANTASTIC improvement.

      I wouldn’t use it server side or for a client application that doesn’t run in a web browser. That’s not its place, for me.

      But I will 100% reach for it every time if I need to run in a JavaScript environment.

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