Rust is for Professionals
gregoryszorc.com
gregoryszorc.com
However, as the manager of a technical team, I would not choose it for professional projects. The learning curve is very steep, and to reap the benefits you have to pay a high cost in terms of accepting additional complexity. I think Rust is a good choice for some professional use-cases, for instance performance-sensitive applications like embedded, or safety-critical applications. But for many applications, like your average webserver for example, I believe you will lose productivity and have a hard time hiring if you choose Rust.
For my team, we chose Go because it is easy to hire and onboard people, the tooling and compatibility story is plenty good enough, and due to the complexity ceiling, there's only so much damage a developer can do in terms of taking the codebase in a bad direction.
Rust is a capable language for a professional setting, but it is also a language ideally suited for people who enjoy indulging in complexity and tricky problem solving, and this is not the right choice for every project or team.
Nope, Rust is also not suitable for these tasks since it doesn't have a certified toolchain (e.g. ISO26262 for automotive or DO-178 for aerospace).
> embedded
Current LLVM-based compiler lacks support for some platforms (e.g. Xtensa for some ESP32 MCUs).
I don't argue whether it's good or bad language. It's a quite interesting one with its own pros and cons. If it fits you, then it's great, but you should know its limitations.
You can read more about the experience here: https://kerkour.com/blog/rust-for-web-development-2-years-la...
The only thing I'm missing is Go's awesome TLS support (with autocert & co).
That being said, I understand your point regarding hiring: a friend of mine totally refuses to learn Rust because the syntax looks not good to him.
Other great things are the ease of packaging with Docker, the low resources usage which helps to keep Heroku's bills small, and the excellent IDE support.
Honestly, I don't feel that I spend time managing memory in Rust: I use ARC pointers for long-lived shared object (Database connections pool, mailer...) and otherwise the ownership is pretty straightforward during the lifecycle of a request, data is moved from the top layer (HTTP handlers) to the bottom (Repositories to access Database) and back for the response.
Does that mean you basically enforce sequential database reads? Seems like a bottleneck if your server is concurrent
If they're sharing a connection pool then each HTTP request would get its own connection out of the pool, and they'd be concurrent (access to the pool may or may not be serialised depending on the pool's details, sqlx is internally mutated not externally locked for instance).
The mailer might be behind a mutex (its access completely serialised), or the "mailer" might just be the input side of a queue / channel, and the actual mailing work be done in a separate process (that seems way more likely than bounding the request on sending emails really).
I am mainly interested to know how much overhead time is spent appeasing the borrow checker and managing memory that would otherwise free up mental cycles if a GC were available . The async story for Rust also seems confusing (but I hold my hands up and plead ignorance on this count).
I don’t think Tony ever did any coding, but you’re right that it still applies here.
A google search shows complexity has many other enemies: security,reliability, agility, and progress itself.
In most cases I think this is right, use Go and simple tools whenever you can. There are cases where complexity is unavoidable though, like when you’re trying to land a rover in a precise location on Mars, where the sky crane makes sense, but don’t introduce the complexity when it’s unneeded.
Prediction is hard. Sometimes I start with something simple, and it ends up growing in scope until it's quite large and complex. Other times I start with something simple, and it stays simple.
So, what's worse, using a complex and/or strict language for something simple, or a simple and less strict language for something that ends up being very large and/or complex?
Interestingly, some people will probably read that last paragraph as my trying to make a point through implication. I suspect different people will assume I'm saying completely opposite things based on their own experience. Really, it's just hard, you get better at making the right choice as you go along, but you'll never always get it right.
So you get sometimes stressful and frustrating writing sessions, coupled with more confidence in the runtime correctness. Also the more expressive type system can allow you to more closely match the domain, which helps when you add new features in the future as you can rule out certain invalid states or interactions.
I often feel you need to know the right conventions to write correct Go programs, where as Rust will just tell you you cannot run it.
I would get things done faster in Go for sure, but the compiled artifact would likely have more issues during runtime.
It seems in your use case, Java would have been a viable (and potentially superior) alternative to golang.
I even abandoned the learn-by-stackoverflow-search approach to rust and read the first seven or so chapters of the rust book. But even that hasn't helped very much. I know I am just currently in the painful, frustrating stage of learning where nothing really makes sense, and at some future point it will all click, but it really can't be overstated just what a wicked learning curve this language has.
Whereas in Rust you know that it's probably possible to use a &str there instead of a String. If you just bang on it a little longer, you can make it just a bit more optimal. The clone()s and the Vec::new()s are all explicit, making them feel heavier than those other languages, when in reality they're still quite a bit lighter.
You usually don't have to optimize them out! Your code will probably be faster than Java even with a bunch of clones, etc! But there's this temptation that's really hard for programmers to resist, to sink hours and hours into making things just slightly more optimal given the opportunity. You have to consciously talk yourself out of that if you want to be productive.
That's… not exactly true. `Vec::new` is completely free so that's a different debate, but much as in C++ or C allocations in Rust are much more expensive than in managed languages:
1. system allocators genuinely suck, all of them, though some more than others (iirc macos' is especially bad)
2. managed languages can much more easily specialised allocation strategies (freelists, bump allocators, type-custom allocation strategies), this is either difficult / impossible (no custom allocators) or way more painful (manually pass custom allocators in) in Rust
As a result, allocations in Rust are really tremendously slow by default, it's not too rare to see questions about Rust programs which are slower than managed equivalents, in release mode. Because the rust program is allocation heavy (relatively), it might have 10% the allocations of the non-rust program but the allocations are 100 times more expensive.
Edit: I do know that languages where strings are immutable use that fact to do lots of optimization (automatically sharing "copied" strings and just cloning reference-counters, for example), but you can accomplish some of this in Rust too with Rc<> or even persistent data structures if you really want to. And of course there are cases where it's more efficient to actually mutate a string, which these languages can't do. But it sounds like you're talking about something else?
That's 100% correct but there's one problem: how do you write down your future improvement opportunities?
Skip 2 optimizations here, 3 optimizations there and after 30 PRs you can easily have notes spanning 100 bullet points on what to optimize one day in the future Soon™.
I am still not at what I'd call an expert level in Rust -- and the skill ceiling is quite high -- so maybe with time I'd start to automatically spot these optimization opportunities?
But before I am at that level I'd prefer to either keep hugely long notes or, ideally, have a tool recommend optimizations to me.
The better tool is to profile the code, then optimize hotspots. There's a Rust Performance Book with a list of profilers known to work with Rust programs[1]. Rustc does support Profile Guided Optimization[2] which is often pretty good at speeding up the output even without any code changes.
[1] https://nnethercote.github.io/perf-book/profiling.html [2] https://doc.rust-lang.org/rustc/profile-guided-optimization....
> The simplest tool is to just grep for various constructs that copy or allocate.
Do you happen to have a curated list somewhere?
Not sure of a list for things that copy their data. The Clone trait is the obvious one, and it requires calling clone() to make the copy. EG `val.clone()`. So searching for `.clone()` will get you those. But other things like to_string are expensive, and From/Into are sometimes expensive.
[1] https://docs.google.com/presentation/d/1q-c7UAyrUlM-eZyTo1pd...
I hope to evolve my understanding so that I can do the right thing at design time to minimize unnecessary clone()s.
- Use a regex to find a string in some text: use regexes, get a &str
- Escape all the regex reserved characters in that string: Okay this requires mutation but we can't mutate a &str, let's loop over the &str's characters (using the Chars iterator) and push them into a new String with the proper escapes
- The new String we own, so we can easily turn it into a regex and use it to search the original string.
As for a "borrow cow", you probably want to read https://doc.rust-lang.org/std/borrow/enum.Cow.html and https://deterministic.space/secret-life-of-cows.html. For what you are doing, it is an optimization to avoid unnecessary clones that is absolutely not required: make your code work with String and worry about Cow<'_, str> later.
And here's my branch (you can see the latest commits to see the file I'm modifying): https://github.com/ahelwer/tree-sitter/tree/testfile-separat...
I haven't had a chance to go through and add clones everywhere, and will be away at a PT appointment for the next hour or so, but would appreciate any pointers you can give.
diff --git a/cli/src/test.rs b/cli/src/test.rs
index ac4807bf..8b9882ab 100644
--- a/cli/src/test.rs
+++ b/cli/src/test.rs
@@ -410,16 +410,17 @@ fn parse_test_content(name: String, content: String, file_path: Option<PathBuf>)
.map(|b| String::from_utf8_lossy(b).to_string())
.map(|s| escape_reserved_regex_chars(&s));
- let suffixHeaderPattern : Option<String> = suffix
+ let suffixHeaderPattern : Option<String> = suffix.as_ref()
.map(|s| String::from(r"^===+") + &s + r"\r?\n([^=]*)\r?\n===+" + &s + r"\r?\n");
- let suffixDividerPattern: Option<String> = suffix
+ let suffixDividerPattern: Option<String> = suffix.as_ref()
.map(|s| String::from(r"^---+") + &s + r"\r?\n");
- let headerRegex = suffixHeaderPattern
- .and_then(|s| ByteRegexBuilder::new(&s[..]).multi_line(true).build().ok())
- .as_ref()
- .unwrap_or(&HEADER_REGEX);
+ let headerRegexFromSuffixHeaderPattern = suffixHeaderPattern.as_ref()
+ .and_then(|s| ByteRegexBuilder::new(&s[..]).multi_line(true).build().ok());
+
+ let headerRegex = headerRegexFromSuffixHeaderPattern
+ .as_ref().unwrap_or(&HEADER_REGEX);
// Identify all of the test descriptions using the `======` headers.
for (header_start, header_end) in headerRegex error[E0382]: use of moved value: `suffix`
--> cli/src/test.rs:416:48
|
406 | let suffix = FIRST_HEADER_REGEX
| ------ move occurs because `suffix` has type `std::option::Option<std::string::String>`, which does not implement the `Copy` trait
...
414 | .map(|s| String::from(r"^===+") + &s + r"\r?\n([^=]*)\r?\n===+" + &s + r"\r?\n");
| ------------------------------------------------------------------------------- `suffix` moved due to this method call
415 |
416 | let suffixDividerPattern: Option<String> = suffix
| ^^^^^^ value used here after move
|
note: this function consumes the receiver `self` by taking ownership of it, which moves `suffix`
--> /Users/ekuber/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/option.rs:451:38
|
451 | pub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Option<U> {
| ^^^^
error[E0716]: temporary value dropped while borrowed
--> cli/src/test.rs:419:23
|
419 | let headerRegex = suffixHeaderPattern
| _______________________^
420 | | .and_then(|s| ByteRegexBuilder::new(&s[..]).multi_line(true).build().ok())
| |__________________________________________________________________________________^ creates a temporary which is freed while still in use
421 | .as_ref()
422 | .unwrap_or(&HEADER_REGEX);
| - temporary value is freed at the end of this statement
...
425 | for (header_start, header_end) in headerRegex
| ----------- borrow later used here
|
= note: consider using a `let` binding to create a longer lived value
let suffixHeaderPattern: Option<String> = suffix
.as_ref()
.map(...);
let headerRegex = suffixHeaderPattern
.as_ref()
.and_then(|s| ByteRegexBuilder::new(s).multi_line(true).build().ok())
.unwrap_or(HEADER_REGEX.clone());
Edit 2: to further drive the point home that this should be a bug, this is the current output for a similar case while I was trying to minimize this:
error[E0308]: mismatched types
--> src/main.rs:10:22
|
10 | .map(|s| bar(s));
| --- ^ expected `&Struct`, found struct `Struct`
| |
| help: consider using `as_ref` instead: `as_ref().map`
`Option::deref` is a good choice here.
If only it was spelled CoW and ARC I would very quickly grasp it (probably).
But it's an extremely minor inconvenience and arguably makes the whole thing very memorable
2. Given you mention "maps of option", probably you are doing something like opt.map(|x| &x.field) or equivalent which is obviously invalid (since you are returning a reference to a subobject of a function argument). Instead, you need to do opt.as_ref().map(|x| &x.field) (or as_mut() if it's mutable).
If you don't really know Rust and in particular understand the borrow checker and how it works (and why it exists), you are going to have a bad time.
Rust in general has a learning curve, but once you do learn it there is a payoff. If Rust code compiles (and if you didn't use 'unsafe'), you can be pretty damn sure it is free of a long list of potential bugs including concurrency bugs, buffer overflows, null pointer dereferences, alignment problems, double-free, use-after-free, stack smashing, most memory leaks, and so on. The runtime cost of that assurance is less in Rust than in any other language I know, and sometimes the safety of Rust actually lets you do things in higher performing ways that would be dangerous to code in C. In C/C++ you have to knit your own straightjacket, and yours may not be as well thought out or efficient as the one the Rust compiler issues you.
I've really started to appreciate Rust's safety. If the code compiles there can still be bugs, but they're going to be higher up at the logic/algorithm level instead of the annoying sorts of bugs that constantly crop up in C/C++.
Problems with well-constrained allocation paradigms do really well in rust. Problems with reading/parsing/storing messy data structures from external data just really, really hurt.
I think a big part of the problem is that the ownership analysis layer has the dual crises of being (1) really complicated and too hard to keep in your head as a single model and (2) specified in an ad-hoc way that resists formal rules. So eventually you end up in of those puzzles like you mention where... there's just no answer! No one's been where you have, and the lack of rigor means you end up trying to reverse engineer the compiler front end trying to find the trick that works. And then you give up and write it in Go or Python or whatever.
It is an error to access a place, when an access conflicts with a loan, and the loan is live.
In fact there are an infinite number of correct Rust programs which will never access memory incorrectly but which will still be rejected by the compiler, for the simple reason that Rust's authors, talented though they may be, have made no progress at all at solving the Halting Problem.
What Rust actually accepts is a subset of correct programs. And this subset is somewhat informally defined as "whatever the compiler could manage to prove". Real code hits against this limit occasionally, and when it does there's really no option other than "join the Rust team" or "try voodoo".
Like all type checking technology, the rule is about static behavior, not dynamic behavior. So halting problem is irrelevant.
Rust accepts all programs that follow the rule in static behavior. It's not a subset, and it's not a best effort to prove. It's the complete statement.
"Access" means source code construct to read or write. Rust doesn't care whether the construct is actually executed in runtime.
let (left, right) = (&mut foo[..split], &mut foo[split..]);
I see these are limitations but not show-stoppers in any way.
Not to belabor this growing thread, but here's the disconnect. I complained the rules were ad hoc and complicated, you replied that they were simple, and when challenged on an edge case your treatment is to add another clause to re-define a term you used in isolation earlier.
That's what "ad hoc and complicated" means.
Actually, my elaboration of "place", local/field/index, is nearly complete. The only thing missing is upvar, which is local captured in closure. Pre-NLL "live" is simple: expression is live from the definition to the end of the containing statement, and declaration is live from the definition to the end of the containing block. Post-NLL "live" is connected region of control flow graph from the definition to potentially multiple last uses. Really, that is the whole story.
There are two changes currently in development. One changes definition of "place" to include field captured in closure, in addition to local captured in closure. The other is more drastic, changing definition of "live": a loan is live where the loan is origin of a variable and the variable is live. This is great, because current approximation is equivalent to union of all origins.
Yes, sure, the rule in question may be simple in the abstract (it's a compiler, after all -- they're just software doing straightforward things). But the ability for the poor programmer to detect which rule is being violated where is a lot more limited than the compiler is designed for. Thus the user with the upthread complaint, which is hardly unique.
I mean, at the end of the day if Rust wants to be an everyday language for this kind of everyday problem, the analysis paradigm needs to be communicated much better to everyday hackers (via docs, error messages, whatever). When Rust was new this seemed like just a technical problem to be solved with software maturity. I guess at this point after several years of regularly returning to play with Rust and being frustrated every time, I've mostly given up.
The unstated problem is that there are patterns from other languages that are actually invalid and Rust is correctly denying, but not properly communicating it, which causes frustration. You can always make the argument that the failure modes are benign or rare, and for those cases noone is stopping you from actually using unsafe.
[1]: https://manishearth.github.io/blog/2015/05/27/wrapper-types-...
And this is why this argument persists. This is, to people outside the community, a semantic evasion:
1. It relies on a Rust-internal definition for "actually valid" (conforming to Rust's specific set of provability requirements) that doesn't correspond to what the rest of the world views as "correct" (not behaving incorrectly). Think about stuff like allocate-through-a-session-and-free-in-a-block paradigms (Apache was famous for this), or run-once-and-exit, or garbage collection, etc... Those things aren't "invalid" in any reasonable sense, they're just not what Rust programs do.
2. The definition for "valid" is (and this is my point above) entirely Rust-internal and ad hoc. It's not that we refuse to conform to your rules, really, it's that we don't know what they are!
> Fun fact: while at Mozilla I heard multiple anecdotes of [very intelligent] Firefox developers thinking they had found a bug in Rust's borrow checker because they thought it was impossible for a flagged error to occur." However, after sufficient investigation the result was always (maybe with an exception or two because Mozilla adopted Rust very early) that the Rust compiler was correct and the developer's assertions about how code could behave was incorrect. In these cases, the Rust compiler likely prevented hard-to-debug bugs or even exploitable security vulnerabilities. I remember one developer exclaiming that if the bug had shipped, it would have taken weeks to debug and would likely have gone unfixed for years unless its severity warranted staffing.
Sometimes people think that they're right and that the compiler is wrong, but often, (not not necessarily always!) it's that they forgot some important piece of context.
(Oh, and Rust absolutely can do "allocate in a block and free at once" stuff, or "run once and exit" stuff...)
To recap, here are the rules:
It is an error to access a place, when an access conflicts with a loan, and the loan is live. Access means source code construct to read or write, whether the construct is actually executed in runtime is irrelevant. Place is static approximation of a set of bytes in the memory. Place is either local (x), field (x.f), or upvar (local captured in closure). Indexing (x[i]) and method calls (x.m()) are approximated as local (x). Loan is either shared (&x) or mutable (&mut x). Read access conflicts with mutable loan, write access conflicts with all loans. Expression is live from the definition to the end of the containing statement. Declaration is live in connected region of control flow graph from the definition to potentially multiple last uses.
Just do the first regex search, then escape into a String with regex::escape, then build a regex from the String and search with it.
Of course what you are doing is probably wrong since you should use a string matching crate rather than escaping characters and using a regex matching crate.
Just lol at the idea that you won't run into borrow checker issues when dealing with strings though.
I think what's being called "trivial" is doing a bit of regex searching. It's probably accurate to call that trivial for an experienced Rust programmer, but if you're just beginning, I don't think it's helpful to call anything trivial. I still remember my first exposure to Rust. It was different. It took a bit to grok. But once it clicked, things were much better.
As the maintainer of the regex crate, I invite you or anyone to ask for help using regexes. The regex repo has Discussions opened up, so it's appropriate to ask for help, even if they are beginner questions: https://github.com/rust-lang/regex/discussions
As usual though, try to provide as many details as you can. Giving the source code you have but can't get to work is a great start, for example.
https://doc.rust-lang.org/rust-by-example/ and https://github.com/rust-lang/rustlings might be good places to visit to gain that experience, as well as improving the specific diagnostics to be more actionable.
Yes, I figured that to be the case, but still wanted to say, "Discussions are open for questions, even if they are beginner related, as long as it's related to regex'ing somehow." :-)
https://play.rust-lang.org/?version=stable&mode=debug&editio...
https://github.com/danielzfranklin/drm-fourcc-rs/blob/main/b...
https://play.rust-lang.org/?version=stable&edition=2018&gist...
But what you really want is to get your head around ownership and borrowing, especially when it comes to the scoped RAII that rust has (e.g. freeing a String while a reference to it still exists and is being used would give you the "temporary value dropped while borrowed" error).
Honestly the friendliness of the community is a big part of why I'm learning Rust. I found it so much harder to get free help from volunteers with c code issues. Not that I deserve it or anything, but it's really nice and I try to contribute back by writing PRs to improve the docs once I understand something.
This took 2 min: https://play.rust-lang.org/?version=stable&mode=debug&editio...
and I don't recall what's the last time I used the regex crate.
I'm certainly doing all the regex stuff incorrectly, no idea how to match regex-reserved characters, no idea if I'm using the iterator API correctly (its the second example in the regex docs..), etc.
But the idea is simple, search the text for the regex, escape all the reserved characters, use that regex to search for occurrences of the same regex.
I guess that if you want a fully-vectorized, zero-allocation, zero-copy, multi-threaded, gpu... version of this that maxes out the theoretical peak of the hardware available, then you'll probably end up putting a considerable amount of work here.
But otherwise, for someone with literally 30 seconds of experience with the regex crate, it was as straightforward to implement as you mentioned. Just c&p their second example, and just added some glue. This is how I'd implement this in Python, or Java...
EDIT: other responses suggest cloning, but that seems to suggest that one has to explicitly and deliberately think about cloning. I instead just played a game of type golf using functions like `.to_string()` or `.collect` to "clone" stuff behind the scenes. My code is probably horrible, but is the first thing that came to mind.
Long suggestion: Working with strings in Rust requires that you have a C++ mental model of what strings are and what properties (in the abstract sense of the word) they have. Rust will make sure you can't misuse them, and it will make them as ergonomic as they can be within that C++-like model, but it's a fundamentally different concept from what you have in languages like C# and Java, and if you're trying to look at things from that other perspective, you're going to keep running into walls over and over.
More broadly, when you're using Rust you need to be in the basic mindset of a C++ programmer. From there Rust will make things significantly easier in many ways, but if you don't start with the right mental model, you're going to have a bad time. Strings are probably the most striking case of this because the way they get treated in virtually all higher-level languages is so wildly different from the way they get treated at the low-level.
I agree with that, but this applied to nearly any language for me. I started doing Python back when 2013, then i learned Go, i started writing better Python code, then i learned C, i started writing better Go code, then i learned Rust, i started writing better code in general. The more you play with other language the more you learn other programming paradigms, it changes the way you thinking about programming completely.
> When you pick up a stone from the pile, it MUST be placed on the wall. You either have to make it fit your intended spot through rotation or another adjustment, or you have to find another place on the wall for it. It CANNOT be placed back on the pile.[2]
The post explains that using this restriction makes you a better masonry overall because you train your self to the exact skills required. I find this a lot better analogy to restrictive programming languages then a straitjacket. When you restrict your self to always place a stone you pick up, you train your eyes to first evaluate which kind of stones you need next, and you train your self to find that stone in a pile. I don’t see exactly what you are training exactly when you wear a straitjacket.
Neither do I.
In my experience, whether you're getting paid or not correlates quite poorly with the requirements of the project. I've worked on professional code bases where bugs were totally acceptable ("just push a fix when the error comes in"), and I've done open-source projects where I definitely don't want anything to break ("I'd hate to release a broken version").
> The statement Rust is for Professionals does not imply any logical variant thereof. e.g. I am not implying Rust is not for non-professionals. Rather, the subject/thesis merely defines the audience I want to speak to: people who spend a lot of time authoring, maintaining, and supporting software and are invested in its longer-term outcomes.
Well, it looks like you're implying some logical variants, like "Rust is a better language than language X for professionals" or "Language Y is _not_ a language for professionals". I mean, "Language X is for Professionals" is true (by observation) for every single language out there being used professionally.
- rust-analyzer is good (as in: it's functional, it's advancing, etc.etc.), but it's alpha; it's not a tool that can be considered a mature tool of a mature language. I often encounter issues while working on projects.
- learning Rust is a serious problem IMHO, not only because it's hard in itself, but it's because it's hard to structure a plan to learn it. listing the reference book is indeed a misrepresentation: a complete beginner that reads the whole book will still have significant problems in working on a real project; it's very unclear which step to take after reading it, as real-world Rust programming needs exercise which is not tackled by any book. Things are made worse by a number of garbage books (Packt being very guilty of this) that pretend to teach programming in Rust by slapping a 20-pages chapter on the syntax and basic concepts.
- "for the vast majority of code I author, Rust feels more like Python than C": feelings are subjective, so I can't argue in an absolute sense, but the complexity of programming is very, very far from Python. In scripting languages like Python/Ruby one doesn't need to care about anything: memory allocation (which in itself, has many consequences, including on the program structure), data types, syntactic rigour, exact consistency of the program (in the sense: one can develop a half broken Python app, and it will stull run); all of these things are required in a statically typed language. Golang is probably a language that is closer to Python than C.
I totally agree. One of the issues is that there are so many complex and novel topics that you will run into in your first week of working on a real project, and you have to wrap your head around all of them to some degree to be able to progress. If there is an obvious and clear progression path, I did not discover it.
> the complexity of programming is very, very far from Python
I could not agree more. These languages are deeply philosophically different in my mind.
That looks like a very long essay / dissertation just to say 'I love rust'.
I'm just not sure the other way will materialize. Until Rust can be used to feed back into C/C++ ecosystems and long-standing projects (like the linux kernel), it'll struggle to be the primary ecosystem / language for non-new (e.g., non-trivial) projects.
The important and exciting new things are written in C++, not Rust. Rust has no advantages over C++ once you know C++.
Realistically, both languages have advantages and disadvantages.
Saying C++ is better than Rust "once you know it" doesn't make a lot of sense to me. No language is intrinsically better once mastered by a productive programmer.
I think you nailed it.
I guess the reverse is also true, if you’re writing the kind of code where failure doesn’t matter (e.g. spikes, experimentation, just messing about) perhaps rust isn’t the best choice.
C demands rigor, too, but we're not talking about C because C compilers don't hold your hand and show you where your rigor slipped. Which is a sign C demands more rigor than Rust, isn't it? It's a problem with the author's argument: It's better to say that both C and Rust demand rigor, because they both compile to low-overhead executables (lower-overhead than C++, certainly), but Rust has more handrails and warning signs than C, so it's less dangerous.
1. provides some unique benefits in terms of safety, and
2. is hard to program and requires rigor
that all that rigor is "worth it", and that it makes you a better programmer to put up with it.
Don't get me wrong, Rust's tradeoffs are valuable for some use-cases, but there are many, many use-cases where a GC'd language will work just fine, and it doesn't make you less professional for choosing a higher level tool which you can be more productive in if you don't have performance or memory constraints.
I also think, as the author alludes to, that many programmers get their first exposure to algebraic types and the elimination of NPE's through Rust, and get the false impression that the benefits of these features are somehow related to the additional complexity required by Rust. But these features are not related. Languages like Swift have shown us that you can get many of the benefits of Rust in terms of providing an "if it compiles it works" experience without many of the challenges Rust imposes on the programmer.
As an example, the rigour of strong typing helps set some experiments on the right track.
I limit my lines to 80 chars for more practical reasons. I have a wide-screen 43" monitor and restricting content to 80 columns allows me to have the project/navigation pane + 4 vertical splits side by side. Couple of those vertical splits can be split horizontally and I can see/edit, say, 6 open files at once without any switching of windows. Probably sounds like overkill but once you experience it, you know its worth it. Plus my eyes like less horizontal scanning too.
It seems like the perpetuation of the use of null-terminated strings is more about interoperability with what came before.
And like you suggest, 80 characters is at the limit of what people generally find comfortable reading. (I rely on editors to word-wrap code on-the-fly rather than insert line breaks manually... maybe that's what was meant? That's a tradeoff, though, since some tools don't do word-wrapping or don't do it well.)
A little bit later I wrote a CLI task runner [2] which is defined by a simple markdown file. I find Rust to be perfectly aligned with the goals of a CLI utility: single deployable binary and very low startup cost.
Most recently I launched a side project [3] (a jigsaw puzzle website) using Rust as my backend API service. I've been slowly building up a server framework over the years and finally was able to put it to use! Yes, it took me much longer to ship something in Rust versus other languages I'm more familiar with. But after learning Rust for a few years now, it doesn't take me much more time to build a feature than it would in another language.
Early on, I ran into a lot of borrower issues and got stuck many times. But after I got over those problems, I realized that for any future hurdles I would face, I just needed to keep pushing and eventually I would find a solution. I have found that with game development or heavily stateful apps, I tend to run into borrower issues more often. But for an API service with a simple input and output, I almost never run into borrower issues.
[1]: https://github.com/jakedeichert/wasm-astar
Now, my biggest critique - because of Rust's emphasis on static dispatch and monomorphization (good decisions all around if you ask me), plus the fact that lifetimes provide their own type dimension - I find that open source projects can have absolutely monstrous types, impossible to reason about. It's tough because I prefer the WYSIWYG templating Rust offers over C++ duck typing any day but many of these crates' types are too complex. In fairness, most of the most egregious cases were due to the lack of const generics and those cases are quickly improving.
As an example, I've been playing around with websockets recently and ran into this type: https://docs.rs/websocket/0.26.2/websocket/server/upgrade/st...
Note 4 different impls, each with its own generic requirements! I'm sure each case makes sense somehow, but it sure complicates my life when I want to use a function and find it isn't implemented for _my_ WsUpgrade.
I think the title is a little bit misleading and paired with the first sentence invites flame, but this one in the middle of article sums it up much better.
With some languages you pay some special costs that are only recovered for certain types of applications.
For example, programming in C is slow, tedious and bug-prone (as compared to Python) but it is easier to solve some types of problems (like writing system software, controlling memory layout for performance, conserve resources, etc.) For most projects the cost may be too high but if you are one of certain types of projects the pros will outweigh the cons.
In general, when programming with strong types you pay for long term maintainability (ability to automatically ascertain correct type of object at any point and extra features that come from it).
In Rust you pay even more for even more benefit in controlling the types and ownership of the data which means this environment should be thought as geared even more towards long term maintainability.
I write typescript for work. I have adapted some concepts such as the encoding invariants into type (using a proven library such as fp-ts and io-ts) and using return over throw for error handling has been yielding better and scalable code.
Not to mention Rust's types for managing concurrency and shared objects, like Rc, Arc, Mutex, that drive the architecture of your software. I have been doing a similar thing in my projects in other language and the impact has been very positive
Edit: typo
This feels like a very powerful assertion. Does the rest of the HN audience agree with this? If this is true, how long did it take?
- Match ergonomics, so that you have to think about borrowing less in patterns
- The compiler providing suggestions for those cases where you must specify them
- Type inference
- Iterators letting you write fairly functional code
Things like having to write &*foo[..] or .as_mut_ref() are indeed "warts" when you don't care about those details, but they happen uncommonly enough that it isn't perceived as an onerous cost.
This isn't strictly true. For instance Swift uses value semantics, which is equivalent to adding an implicit `.copy()` in rust every time most variables are passed around. It obviates a lot of the low-level details, at the cost of performance and control. This is a lot more "python-like" in my opinion, where having to hold these details in your mind is very much against the design priorities of python.
Python wants everything to be implicit, to eliminate tedium wherever possible, and for syntax to barely exist. By contrast Rust favors explicitness, demands a lot ceremony, and is very syntax-heavy. These languages are antithetical in so many ways.
It's fairly subjective, so I would not try to convince you that Rust is more similar to C than Python, but many of the points you brought up apply to virtually every modern mainstream language. It's hard to imagine why Python would come up as a comparison point for Rust unless C and Python were literally the only other languages you had ever programmed with.
I guess one could say APIs expose functionality on the level somewhat similar to C++, with builtin strings, vectors, and other high level data structures that are namespaced and are also objects. Whether that is more C-like or Python-like is for the reader to answer.
You can sorta kinda compare programs though. I had a discussion about this on HN last year. Note that this is an extremely small sample size, but you know https://news.ycombinator.com/item?id=22712441
I wrote an updated version half a year ago https://news.ycombinator.com/item?id=24595081
YMMV. It depends on a lot of factors.
> The statement Rust is for Professionals does not imply any logical variant thereof. e.g. I am not implying Rust is not for non-professionals.
He must be joking.
Erlang has the best pattern matching abilities and it is all around in every single Erlang code I have ever seen.
> Many of the new concepts weren't novel to Rust. But considering I've had exposure to many popular programming languages, the fact many were new to me means these aren't common features in mainstream languages.
And… they're right. Other languages cropped up with overlap around the same time (mostly Swift), but sum types, pattern matching, option types, … were not common features, and borrow checking remains rather unique.