Comment by blub | Hacker News Reader

Comment by blub | Hacker News Reader

Parent Full thread

These Rust discussions typically contain grains of truth wrapped into exaggerations while downplaying or ignoring the two big issues of Rust, which are complexity and out of control dependency trees.

For the first issue of complexity, the reply is along the lines of show me the code and then either nitpicking that to pieces or explaining in several paragraphs how the behavior is perfectly reasonable and in fact quite easy to understand. Beginners get intimidated, professionals don’t have time to write novels on HN. Complexity in Rust is systemic. It’s little things accumulating and amplifying each-other that add up to having to spend significant time just designing types to satisfy the static analyzer. Many Rust programmers seem to see the type system as a hammer to be used liberally, an predilection also known in the C++ metaprogramming community.

On the second topic (also present in this thread) the counter-argument is that other languages do it too and nothing bad happened so far. The former is not valid, because Rust is uniquely bad in its competitor group and security by waiting is not a valued approach.

I would argue that what you call complexity here is better referred to as explicit or visible complexity, as compared to hidden or implicit commplexity. The complexity as such comes with the domain and its application; but with Rust you can see it and you are forced to deal. With C++ you can get away with pretending that it is in fact not there.

This is honestly not intended to pick on C++ as a Rust fanboy, however. It really isn't.

For instance, to be a little unpolished, I would shrug off the unwrap incident as doing it the C++ way and pretending that the complexity does not need to be solved right then and there because ItShouldNotHappen or IKnowWhatIAmDoing.

I prefer Rust over C++, but I do not hate C++. This isn't even about C++ anyway.

When it comes to out of control dependency trees, I agree with you. But there is a trade off here too and that is that either you implement the thing or you externalize it. I use both approaches myself and am in no way excusing anything or attempting to be Rust's defense lawyer. There definitely seems to be a leftpad-problem brewing in the Rust community.

There are certainly good parts in Rust that force you deal with inherent issues explicitly. I do not think this justifies a language with the complexity of Rust, but I would agree it is preferable to C++ in this regard.

I reject the whole Rust has a high complexity premise, but I would gladly continue our conversation around it here but I would need a little more definition for that to be possible.

What do you mean by complexity in this context and in what way does Rust carry a lot of it?

I did not know this was disputed, as even developer surveys in the Rust community highlighted complexity as a concern. But seems it is the overall summary of features that make it complex: lifetime, borrowing, a polymorphic type system, traits, multiple tools to manage lifetimes, macros, proc macros, async, unsafe, panic, unwrap, etc. But I agree it is much cleaner than C++.

Still not picking on C++ here. I would claim that these concepts pretty much all exist in C++ too, but often implicitly so. You would solve them by "braining them", with good rules of thumb, patterns, tests and deep knowledge and skill. In fact, you _have_ to solve them this way.

In Rust the compiler is going to have a problem with your code unless you are explicit about borrowing/ ownership, gcc won't care. Which is the more complex thing there?

Same goes for the polymorphism. Looking at languages without parametric polymorphism, you instead see casts and inheritance trees. Not picking on old Java here, but is this more or less complex?

Let's talk some about unsafe as well. In C or C++, for instance, there is a global unsafe surrounding all the code, so if someone has problem with unsafe, why would they pick on Rust where "unsafety" is optional?

Same goes for unwrap. Unwrap is basically a deref combined with a _safe_ crash if the deref was not successful at runtime. Do that in an unsafe language and you have an access violation best case. Or just silent corruption. Which is more complex?

I'm a really big fan of Rust, but I have to challenge this, GP was clearly talking about the complexity of the language itself, and that one is high.

Extra features and extra static checking add complexity. Extra complexity in the language can make simple programs harder, and they make complex programs easier to code and maintain, like you said.

However, nobody will ever be able to make a Rust equivalent of TinyCC, the language's rules are insanely complex, especially for things like GATs and the other tricky concepts it's trying to tackle.

Unless you or him define what you mean by complexity, we are not going to be able to come to an agreement there. This line of reasoning, it seems to me, is making the case that C is more complex than Assembly because the former has a number of formalizing, let's say, concepts that are not in assembly.

I would on the contrary say that adding extra static checking deducts from the _actual_ complexity of the domain and its application.

By complexity I mean roughly the number of language rules / techniques / idioms a programmer has to understand and keep in their head to be able to program effectively. I would say this is far lower in C than in Rust. I do not see how the additional hoops Rust makes you jump through makes it easier to achieve a goal, but I see how it can help prevent certain errors (but not many others).

It also seems obvious that the problematic aspect of getting anything done in Rust is fully compensated by having a lot of libraries available quickly via Cargo, so people are essentially just assembling things at a high-level. And in principle, I think this is a very good thing, but in the way this is implemented it comes with severe supply chain risks.

I guess that depends on what goals you have in mind. If they are producing a correct program, then having the compiler verify your assumptions, forcing you do deal with domain complexity upfront is one way to do that. Tests( driven development) is another one.

But in this context I feel that partial solutions are offered as alternatives to more complete ones. I.e.: if holes in your trousers is of no concern, then having tools to avoid that is of no value.

Not picking on C here, as already mentioned, it is a wonderful language.

In my experience is it also possible to avoid most holes in the trousers easily with C as well and not just by testing. For example, it is also often possible to build safe abstractions by designing an API around an incomplete type etc.

C is turing complete so of course. You can do anything with C but that is not the issue we are discussing here.

Reply on news.ycombinator.com