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Choosing Rust for new projects is very different than trying to rewrite an existing codebase with thousands of hours poured into it. Or worse, demanding that so

by WJW 1y ago

Choosing Rust for new projects is very different than trying to rewrite an existing codebase with thousands of hours poured into it. Or worse, demanding that someone else do that for you for free.

laerus 1y ago
Rewriting could also make sense if there is a chance to improve the architecture based on the experience with the existing codebase. Something that would otherwise be impossible to even consider.
josephg 1y ago
People keep saying this. But in my experience, directly porting code from one language to another is much easier that people think. I can do maybe about 500 lines per day depending on the language similarity. ChatGPT is great for doing a first pass - though it will add small, subtle bugs in the process. I’m not arguing that we should rewrite everything in rust. C and C++ are fine languages. But sometimes it really is better to just have your code in a different language rather than deal with FFI. For example, I have some collaborative text editing code in rust and recently I just ported the whole thing to typescript, because it’s just straight out easier to use in a browser that way, compared to dealing with a wasm bundle. I think the big mistake people make when rewriting into a different language is doing a refactor at the same time. This is the wrong way to go about it. First port directly the code you have. Then port your tests and get them passing in the new language. Then refactor. Obviously there’s always some language differences - but ideally you can confine differences within modules, and keep most of the module boundaries intact through the rewrite. You can also refactor before translating your code. If I were porting something to rust that wouldn’t pass the borrow checker, this is probably what I’d do. First refactor everything to make the borrow checker happy - so for example, make sure your structs / classes are in a strict tree. Then get tests passing. Translate between languages and cleanup. If you approach it like that, rewriting code is a largely mechanical process. It really takes a lot less time than people think to translate code, since you don’t actually have to understand every single line to do it correctly. So the time taken scales based on the number of lines of code. Not the number of hours it took to write! And then, if you want to refactor your new program at the end, go for it.
- neilv 1y ago
  > ChatGPT is great for doing a first pass - though it will add small, subtle bugs in the process. Kill it with fire.
  - neilv 1y ago
    Downvoters: The whole point of Rust is avoiding defects due to programmer mistakes. Why would you use Rust, but then outsource the programming to a known-bad programmer/plagiarizer.
    - setr 1y ago
      Isn’t that exactly why If rust avoids defects due to programmer mistakes, then throwing a shitty programmer at it is functionally safe (or safer than otherwise) because their shitty code won’t compile. So worst case is they don’t do any harm, and best case is free cheap labor
      - neilv 1y ago
        Rust only prevents/discourages some classes of programmer mistakes. But presumably your you want to reduce all of the mistakes. Rust won't prevent/discourage a lot of the other classes of mistake that a bad programmer is creating.
        setr 1y ago
        Sure but generally speaking, the safer the language/model/api, the more likely you can get away with AI generated code. Rust having more powerful modeling tools than the usual language sales it more viable to use crappier programmers, not less. Obviously if your goal is perfection, then only hire programmers capable of writing perfection. If you’re making the trade-off of cheaper/junior resources and putting more effort into testing/api design/type design/code review to help defend against the inevitable errors, then your genai code fits neatly into the same equation
- chrismorgan 1y ago
sshine 1y ago
Yes, those are different experiences. But assuming you're experienced with Rust, porting something is actually both easy and enjoyable. Porting something as your first Rust project is going to end up like a dirty hybrid. It's an excellent learning opportunity, but it will not leave a good showcase of Rust.
IshKebab 1y ago
Yeah it depends on the project I think. There have been quite a lot of successful rewrites of large projects into Rust. For example Fish and svgr.

by WJW 1y ago

Choosing Rust for new projects is very different than trying to rewrite an existing codebase with thousands of hours poured into it. Or worse, demanding that someone else do that for you for free.

laerus 1y ago

Rewriting could also make sense if there is a chance to improve the architecture based on the experience with the existing codebase. Something that would otherwise be impossible to even consider.

josephg 1y ago

People keep saying this. But in my experience, directly porting code from one language to another is much easier that people think. I can do maybe about 500 lines per day depending on the language similarity. ChatGPT is great for doing a first pass - though it will add small, subtle bugs in the process. I’m not arguing that we should rewrite everything in rust. C and C++ are fine languages. But sometimes it really is better to just have your code in a different language rather than deal with FFI. For example, I have some collaborative text editing code in rust and recently I just ported the whole thing to typescript, because it’s just straight out easier to use in a browser that way, compared to dealing with a wasm bundle. I think the big mistake people make when rewriting into a different language is doing a refactor at the same time. This is the wrong way to go about it. First port directly the code you have. Then port your tests and get them passing in the new language. Then refactor. Obviously there’s always some language differences - but ideally you can confine differences within modules, and keep most of the module boundaries intact through the rewrite. You can also refactor before translating your code. If I were porting something to rust that wouldn’t pass the borrow checker, this is probably what I’d do. First refactor everything to make the borrow checker happy - so for example, make sure your structs / classes are in a strict tree. Then get tests passing. Translate between languages and cleanup. If you approach it like that, rewriting code is a largely mechanical process. It really takes a lot less time than people think to translate code, since you don’t actually have to understand every single line to do it correctly. So the time taken scales based on the number of lines of code. Not the number of hours it took to write! And then, if you want to refactor your new program at the end, go for it.

neilv 1y ago
> ChatGPT is great for doing a first pass - though it will add small, subtle bugs in the process. Kill it with fire.
- neilv 1y ago
  Downvoters: The whole point of Rust is avoiding defects due to programmer mistakes. Why would you use Rust, but then outsource the programming to a known-bad programmer/plagiarizer.
  - setr 1y ago
    Isn’t that exactly why If rust avoids defects due to programmer mistakes, then throwing a shitty programmer at it is functionally safe (or safer than otherwise) because their shitty code won’t compile. So worst case is they don’t do any harm, and best case is free cheap labor
    - neilv 1y ago
      Rust only prevents/discourages some classes of programmer mistakes. But presumably your you want to reduce all of the mistakes. Rust won't prevent/discourage a lot of the other classes of mistake that a bad programmer is creating.
      - setr 1y ago
        Sure but generally speaking, the safer the language/model/api, the more likely you can get away with AI generated code. Rust having more powerful modeling tools than the usual language sales it more viable to use crappier programmers, not less. Obviously if your goal is perfection, then only hire programmers capable of writing perfection. If you’re making the trade-off of cheaper/junior resources and putting more effort into testing/api design/type design/code review to help defend against the inevitable errors, then your genai code fits neatly into the same equation
chrismorgan 1y ago

sshine 1y ago

Yes, those are different experiences. But assuming you're experienced with Rust, porting something is actually both easy and enjoyable. Porting something as your first Rust project is going to end up like a dirty hybrid. It's an excellent learning opportunity, but it will not leave a good showcase of Rust.

IshKebab 1y ago

Yeah it depends on the project I think. There have been quite a lot of successful rewrites of large projects into Rust. For example Fish and svgr.