Why is Rust difficult? • Hacker News Board

Re: Why is Rust difficult?

#11

Post by bitL » Mon, Jan 22, 2018, 6:08 AM UTC

cortesoft wrote: post #8

bitL wrote: post #4

Isn't the problem with Rust that it uses crappy pessimistic heuristics (borrow checker) for essentially NP-C problem, causing complaints where code is perfectly OK? IMO interesting design decision but I am staying away precisely because of this.

I think this comes down to philosophy; do you want the compiler to just check that the program works for all the current parts, or to have the compiler make sure that the program will work for all the possible ways the interfaces can be used as described? Basically, Rust makes you ensure that your code can actually do all the things it says it can do, not just the things it is currently doing. Personally, I find that…

I'd love if it were able to predict correctness of the program, but it can't (halting problem something). It can only approximate it and to be meaningful, it has to be pessimistic. Which is one more headache to casual developers.

Re: Why is Rust difficult?

#12

Post by tatterdemalion » Mon, Jan 22, 2018, 6:09 AM UTC

bitL wrote: post #9

tatterdemalion wrote: post #6

Earlier quoted context omitted.

Do you stay away from all type systems? This would be an accurate negative framing for any type system, which all necessarily reject some correct programs.

Not really. Just it's super difficult to understand how exactly borrow checker operates and when would it allow program to compile or not, causing all kinds of unpredictable situations and unless you are "black belt"-level, difficulty providing any estimates. Not mentioning loss of morale when you have to fight it every single day.

This is not my experience using Rust. I had six months of programming experience when I first tried Rust. I definitely got confusing errors at first, but I grasped the system within a month or two. And that was in 2014 - the borrowchecker and especially its errors have way improved since then!

But this is also a very different objection from your initial objection, which was just a statement of fact about type systems for turing complete languages.

Re: Why is Rust difficult?

#13

Post by kumarvvr » Mon, Jan 22, 2018, 6:10 AM UTC

After years of using Python, it's been difficult to wrap my head around GO and Rust.

I really wish there was a course on Rust / Go for python programmers.

Re: Why is Rust difficult?

#14

Post by sillysaurus3 » Mon, Jan 22, 2018, 6:12 AM UTC

Is there a way to avoid the true-believer syndrome for Rust?

I want to embrace Rust, but everyone ~100% of the time comes away chanting about how awesome Rust is. So much so that it's a bit unsettling. Zealotry in general is bad, but especially in programming: once you identify as an X programmer, you lose out on ideas from Y and Z.

Every tool has its flaws, but for whatever reason it seems extremely rare to discuss Rust's. When you try, it's like you're the Pied Piper: your song brings seemingly the entire community scurrying towards you, ready to force-push you why you're wrong and why Rust is awesome.

How about no REPL? We Go now. Slow compiler? Check. Performance is nice, and so is parallelism, but it costs static typing. It's a nice tool to have in your pocket as a fallback, but where's the niche? The ecosystem is huge, too: run `du -hs ~/.cargo/` and see how many GBs you're losing. This is a really tough sell on a 256GB SSD.

"So get a bigger SSD!" "Yeah but the compiler is always improving" "Yes but real programmers don't really need a REPL" "Yeah but static typing is worth the tradeoffs"

These refrains have been identical for nearly a year. Is there anything new to say, or is it time to agree to disagree?

Re: Why is Rust difficult?

#15

Post by SamReidHughes » Mon, Jan 22, 2018, 6:13 AM UTC

bitL wrote: post #9

tatterdemalion wrote: post #6

Earlier quoted context omitted.

Do you stay away from all type systems? This would be an accurate negative framing for any type system, which all necessarily reject some correct programs.

Not really. Just it's super difficult to understand how exactly borrow checker operates and when would it allow program to compile or not, causing all kinds of unpredictable situations and unless you are "black belt"-level, difficulty providing any estimates. Not mentioning loss of morale when you have to fight it every single day.

Is it? Could you give an example? I've found a borrow checker bug in the current release but the rest of the time its behavior is perfectly predictable. Granted, I wouldn't be surprised if the documentation was horrible, my understanding of the checker is based on one way I would do it.

Re: Why is Rust difficult?

#16

Post by tatterdemalion » Mon, Jan 22, 2018, 6:15 AM UTC

stmw wrote: post #2

Good article, although there are also some unforced errors of what Rust community calls "ergonomics" - many of which have been addressed, and hopefully many others will be soon - that make things more difficult to learn than the absolutely have to be. But author is quite correct that some things are just hard, and if a language is being "honest", it must expose them to the user.

What we could do better than we do today - and your comment about ergonomics alludes to our work to improve this - is ease the onboarding of that complexity we have to be "honest" about. Its a design constraint of Rust that it must maximize user control, but that does not imply that users have to be faced with all of those choices as soon as they first try to write Rust. In some respects I think this article is an attempt at a counterargument to that work (suggesting that it is "dishonest") but I fundamentally do not believe that there is a contradiction between giving advanced users control and making it easier for new users to write correct code before they have a full understanding of the entire system.

Re: Why is Rust difficult?

#17

Post by eridius » Mon, Jan 22, 2018, 6:16 AM UTC

sillysaurus3 wrote: post #14

Is there a way to avoid the true-believer syndrome for Rust? I want to embrace Rust, but everyone ~100% of the time comes away chanting about how awesome Rust is. So much so that it's a bit unsettling. Zealotry in general is bad, but especially in programming: once you identify as an X programmer, you lose out on ideas from Y and Z. Every tool has its flaws, but for whatever reason it seems extremely rare to discuss…

I find it pretty strange to read you say "it costs static typing". Static typing is a feature. There's a reason people are starting to switch to TypeScript instead of JavaScript.

Re: Why is Rust difficult?

#18

Post by deepGem » Mon, Jan 22, 2018, 6:18 AM UTC

sillysaurus3 wrote: post #14

Is there a way to avoid the true-believer syndrome for Rust? I want to embrace Rust, but everyone ~100% of the time comes away chanting about how awesome Rust is. So much so that it's a bit unsettling. Zealotry in general is bad, but especially in programming: once you identify as an X programmer, you lose out on ideas from Y and Z. Every tool has its flaws, but for whatever reason it seems extremely rare to discuss…

"Yes but real programmers don't really need a REPL" I'm hearing this for the first time. I don't call myself a real programmer but REPL is a godsend. There's no quicker way to test something - a small function, a numpy matmul etc

Re: Why is Rust difficult?

#19

Post by bitL » Mon, Jan 22, 2018, 6:21 AM UTC

SamReidHughes wrote: post #15

bitL wrote: post #9

Earlier quoted context omitted.

Not really. Just it's super difficult to understand how exactly borrow checker operates and when would it allow program to compile or not, causing all kinds of unpredictable situations and unless you are "black belt"-level, difficulty providing any estimates. Not mentioning loss of morale when you have to fight it every single day.

Is it? Could you give an example? I've found a borrow checker bug in the current release but the rest of the time its behavior is perfectly predictable. Granted, I wouldn't be surprised if the documentation was horrible, my understanding of the checker is based on one way I would do it.

It's simply one more thing you need to keep in your internal "context" while writing a program, taking mental resources you could spend elsewhere. Perhaps an IDE guiding you and outright rejecting the code or offering code completion that is compatible with borrow checker might be a solution, though we aren't there yet I believe.

Re: Why is Rust difficult?

#20

Post by tatterdemalion » Mon, Jan 22, 2018, 6:21 AM UTC

sillysaurus3 wrote: post #14

Is there a way to avoid the true-believer syndrome for Rust? I want to embrace Rust, but everyone ~100% of the time comes away chanting about how awesome Rust is. So much so that it's a bit unsettling. Zealotry in general is bad, but especially in programming: once you identify as an X programmer, you lose out on ideas from Y and Z. Every tool has its flaws, but for whatever reason it seems extremely rare to discuss…

- We are directing material resources (as in, hours of paid work) to improving compiler performance. We consider this a serious problem, and "the compiler performance is always improving" is not an accurate gloss of the amount of work people are putting into solving it.

- We would love to have a REPL but there are nontrivial technical challenges, and it has not been a major requested feature by our users.

- I have never heard the complaint about the size of packages before now; I have no idea how we compare to other languages in this regard.

I've witnessed some of the conversations you're talking about (I think I engaged with you about REPLs in the past), and I think the "true-believer syndrome" has more to do with how you interpret the answers you receive than with the behavior of anyone else.