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0 pointsdonuteaters10y ago0 comments

I really wish Rust was as great as you advocates say, but that has not been my experience. For background: I've been following it for a while now. About a year or so ago, I dove it into with enthusiasm, but I got bit when the sigils went away, and so I backed off until the 1.0 release. After the 1.0 release, I figured it was ready so I spent another couple of weeks learning the new way of things and really hoping that it would be my replacement for C and C++. I really wanted Rust to be great.

Unfortunately, it has lots of warts that have sent me crawling back to C++. Addressing the particular item you're talking about here, manually specifying lifetimes of objects is a cure that's worse than the disease. It's great when the compiler infers everything for you, but I'm never going to be able to explain the syntax or semantics of those ugly 'a marks to my coworkers who aren't interested in programming language theory.

Anyways, I've been tempted to write a full blog post listing all of my Rust complaints, but I figured it's better to just quietly let you guys enjoy your thing. However, whenever I see these advocacy posts from you and the other Rust honchos, I can't help but scream a little bit inside. It's really not as good as it could've been.

To be really specific: it's great that you got "zero-overhead memory-safety", but I can't even implement fundamental data structures without using unsafe blocks and lifetime annotations.

0 comments

kibwen10y ago

Don't hold back! :) Criticism helps us improve, as long as you can make it constructive and make at least a cursory effort to understand Rust's goals. As I've said elsewhere, if memory safety isn't a priority for your product then Rust may not be for you.

As for the lifetime annotations, we could be extending lifetime elision to more places, including to struct definitions, if people come up with rules that are easy enough to understand. I'd probably be for it, but there are others who think that if you go too far toward removing lifetime annotations then you actually make programs more difficult to understand and the language harder to teach. But that was also the argument against our current lifetime elision rules, which are pretty fantastic in retrospect, so I'm not particularly swayed.

Jweb_Guru10y ago

I hate our current lifetime elision rules, as do many people who have been using Rust for a while. There was an RFC (which was closed) to add some back. IMO, the rules largely exist for the sake of making short examples look less threatening, rather than because they actually make Rust more usable.

Tyr4210y ago

I feel like the explicit lifetime annotations just move the invariants from the comments to the code. So I feel like it's a good thing to make explicit. I could be wrong as projects get larger though.

Though I do feel a bit let out after reading http://cglab.ca/~abeinges/blah/turpl/_book/vec.html which implements Vec from scratch, as it's not super simple.

But really, that would be impossible in Go, just as tricky in C++ (if you make it stl compatible), and impossible in implement generically without lots of void* stuff in C, so I guess I wasn't sure what I was expecting. It's a pain to implement fundamental data-structures I guess.

Still, if you've got anything new to say, go ahead and say it.

pcwalton10y ago

What, specifically, would you want to have Rust do instead regarding lifetimes?

It sounds like you don't want memory safety without garbage collection, based on your last paragraph, and that's totally fine! My use cases aren't necessarily your use cases, and I don't want to claim that everyone who truly doesn't care about zero-overhead memory safety is wrong. But I think it's defensible that memory safety is an important feature for many projects (for example, the ones I work on) in 2015, even if it results in an additional learning curve. The disease we're trying to cure is a never-ending stream of security vulnerabilities and crashes in systems code, and none of the attempts to solve the problem that have existed so far have worked.

Nadya10y ago

>Anyways, I've been tempted to write a full blog post listing all of my Rust complaints, but I figured it's better to just quietly let you guys enjoy your thing

Please do. I'd love to hear your thoughts on issues.

Shorel10y ago

What is your opinion of D?

Do you think when the standard library is totally GC free it would be good for your use cases?

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