Comment by afdbcreid | Hacker News Reader

Comment by afdbcreid | Hacker News Reader

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You'd be surprised to see, after deep inspection, how little of Rust you can remove while keeping its safety story the same (that is, memory safe without GC).

Traits? Nope. We need some way for code reuse. Classes cannot be made memory safe without extra cost (at least, I don't know how can they). And they are not less complex either. Templates like C++? More complex, and doesn't allow defining safety interfaces. No tool for code reuse? That will also severely limit the safety (imagine how safe Rust was if everyone would need to roll their `Vec`).

The borrow checker of course cannot be omitted. ADTs are really required for almost anything Rust does (and also, fantastic on their own). Destructors? Required to prevent use after free.

Async can be removed (and in fact, wasn't there in the beginning) which is a large surface area, but even today it can mostly be avoided if you're not working in some areas.

I don't think anybody can deny Rust is complex, but most often it's inherent complexity (what you call "sophistication") given the constraints Rust operates in, not accidental complexity.

Absolutely this. Folks are used to an awful lot of the complexity being hidden from them through avoidance of threading, runtimes, garbage checkers, standard libraries, and so on. For a language which exposes all of the complexity, Rust feels minimalist. C++ is one of a small number of other languages which also expose all the complexity, and it feels gargantuan and like poorly-thought out additions after additions by comparison. I don't mean to disparage the C++ devs at all, C++ has managed to be useful for ~40 years, and it's still capable of incredible things. Just that we've learned a lot over those 40 years, and computational capacity has grown significantly, and Rust has had the opportunity and architecture to integrate some of that learning more fundamentally.

Somehow most of the libraries in the Rust ecosystem seem to interoperate with each other seamlessly, and use the same build system, which I didn't have to learn another unrelated language to use! Astounding!

> Traits? Nope. We need some way for code reuse.

Says who? You can totally do code reuse using manually-written dynamic dispatch in "rust without traits". That's how C does it, and it works just fine (in fact, it's often faster than Rust's monomorphic approach that results in a huge amount of code bloat that is often very unfriendly to the icache).

Granted, a lot of safety features depend on traits today (send/sync for instance) but traits is a much more powerful and complex feature than you need for all of this. It seems to me like it's absolutely possible to create a simpler language than Rust that retains its borrow checker and thread safety capabilities.

Now whether that'd be a better language is up to individual taste. I personally much prefer Rust's expressiveness. But not all of it is necessary if your goal is only "get the same memory and thread safety guarantees".

> Says who? You can totally do code reuse using manually-written dynamic dispatch in "rust without traits". That's how C does it, and it works just fine.

Rust can monomorphize functions when you pass in types that adhere to specific traits. This is super-handy, because it avoids a bounce through a pointer.

The C++ equivalent would be a templated function call with concept-enforced constraints, which was only well-supported as of C++20 (!!!) and requires you to move your code into a header or module.

Zig can monomorphize with comptime, but the lack of trait-based constraint mechanism means you either write your own constraints by hand with reflection or rely on duck typing.

C doesn't monomorphize at all, unless you count preprocessor hacks.

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