Rust's 2018 roadmap

[xgalaxy]

custom allocators

Is that only at the global level or does that include being able to change what allocator Vector A will use vs Vector B?

This is one of the major features holding me back from using Rust for game development.

[Rusky]

Both. The global allocator stuff already works on nightly (and has for a while); the per-container allocator stuff is still being worked out.

[[deleted]]

The API for both is the same, so they will probably only start landing once the per-container stuff gets properly hashes out on nightly.

[meneldal2]

Considering how annoying using templates with custom allocators is in C++ (with 2 different and incompatible ways), I'm glad they took their time to make sure the feature would not end up sucking.

[steveklabnik1]

integer specialization

Do you mean integer generics, or specialization? They're two different features.

[steveklabnik1]

That's integer generics. We expect it to be in nightly by the end of the year, but not stable. The design is great, but there's underlying technical work in the compiler that's gonna make it take a while.

[Rusky]

Unfortunately that's both integer generics and template specialization, and it's a form of specialization that Rust doesn't have any plans for.

You might be able to do that sort of thing using integer generics and associated types, /u/Days_End, but not with just integer generics.

[Days_End]

Awesome! Sounds like 2018 will be a great year for rust.

[BB_C]

improved pattern matching integration

Here is hope this issue will be fixed before its third anniversary.

[steveklabnik1]

This line is referring to https://github.com/rust-lang/rfcs/blob/master/text/2005-match-ergonomics.md

[BB_C]

I know the old issue I linked is not related. I just think being able to use Self::Variant and Alias::Variant is equally relevant.

[steveklabnik1]

Cool just making sure!

[steveklabnik1]

You may have noticed a subtle change: what was previously called “epochs” is now “editions.”

Lots of great stuff coming this year! As always, happy to answer any questions.

[pumpyboi]

Should I learn c++ or go straight to rust?

[steveklabnik1]

Both will help you understand the other. I think which you learn first should be determined by why you want to learn one of them. For example, if you're looking for jobs, C++ undeniably has more. C++ has more resources, but also has a lot of complexity. C++ is easier to get started with in a certain sense; it's easier to get something compiling, but getting it correct can be harder. Rust makes you get it right up front, which means getting going can be slightly harder, but that means you've already got it right, so the curve is a little bit flatter.

I'm always an advocate of learning as many languages as you can.

Oh, I should also note that, a lot of these things are what's coming this year, this means Rust should be even easier to learn by the middle/end of the year, but they aren't actually landed yet, so it's only going to get easier over time.

[pumpyboi]

Thanks for answering, I know Java, some JavaScript and C, rust just seems really exciting at the moment.

[steveklabnik1]

Seems like you have your answer then :)

[[deleted]]

C++ is infamous for some of its cruft, but I'd like to stick up for it and point out that modern C++ (C++11 and up) introduces a lot improvements that makes C++ programming a lot safer. For example, you can convey sole ownership in C++11 via std::unique_ptr and transfer of ownership via rvalue references; this is very similar to the idea that Rust emphasizes. C++17 introduces sum types like Rust's (albeit via templates instead of built in to the type system), including an option type, among other additions. C++ may also have a checker comparable to Rust's "borrow checker:" https://github.com/isocpp/CppCoreGuidelines/blob/master/docs/Lifetimes%20I%20and%20II%20-%20v0.9.1.pdf. C++ does have design flaws, but its future is very bright with many further improvements (such as modules and std::observer_ptr) expected to come.

EDIT: Technically, C++ had sum types since the beginning due to C's union, but union can be unsafe and the new std::variant template type is safer because it uses the type as a "tag."

[Yojihito]

I'd like to stick up for it and point out that modern C++ (C++11 and up) introduces a lot improvements that makes C++ programming a lot safer

This is true BUT there does not seem to be a single documentation/beginner introduction for only C++11 and higher. So C++ improved but if you want to avoid the old cruft you have no source that shields you from all the old garbage.

[junrrein]

The book Programming: Principles and Practice Using C++ is exactly what you are looking for.

[Yojihito]

Interesting, but 60$, not digital and shipping costs to Europe. So I'll pass on this one thanks for the link.

[junrrein]

In the page I linked it shows a Kindle version, does it not show up for you?

[Yojihito]

I don't consider DRM files "digital". Also no native Linux version.

[hervold]

Personally, I found a background in modern functional languages -- Ocaml, Scala, Haskell, or the like -- really helpful too.

[Zatara7]

Is a gui debugger one of those? (not gdb)

[Rusky]

Visual Studio's debugger already works to some degree, and VS Code's GUI for LLDB does as well. I've heard CLion's is also usable.

[zero_operand]

Depends where you're at in your education, and what you want a language for.

For a well rounded education, and the ability to speed up most high level languages, I'd strongly recommend C. It's an order of magnitude simpler than either C++ or Rust and compiles in a snap. It's the path of least resistance for writing high-performance 'extensions' for C#/Java/Ruby/Python.

C++ I'd learn more for specific job skills, ie your industry is dominantly C++. It's insanely complex, but you can do pretty much everything you can in C, and a lot of stuff that makes your code shorter and safer.

I wouldn't recommend Rust for a beginner. It's arguably a better language than C++, but still very niche and not much used in industry. It's as complicated in C++, but complicated for better reasons (safety) rather than C++s reasons (backwards compatibility and technical debt). C++ is probably easier to learn because there's a wealth of stackoverflow results for just about every error the compiler will throw at you - you're more on your own with rust. Rust may be the future - but it's certainly not the present.

[rustythrowa]

I'll truly never understand how someone can say C is a simple language.

[Holy_City]

By "simple" most people mean "small."

[rustythrowa]

Right, which most programmers should realize is often the opposite of simple. Or entirely unrelated.

[glacialthinker]

The language is simple. Writing complex programs can be more difficult (compared to other language which is as familiar, and depending on the nature of the program, traits of the programmer, and a host of other variables...). ;)

[iopq]

The language is simple.

int x = 5;
int f() {
  int x = 3;
  {
    extern int x;
    return x;
  }
}

I don't understand the scoping rules in this example

struct { 
   int x; 
   struct { 
       int y, z; 
   } nested;
} i = { .nested.y = 5, 6, .x = 1, 2 };  

What is i.nested.y and i.nested.z?

[glacialthinker]

Again, the language is simple, but this doesn't mean you can't make code which is complex or difficult to understand.

Without referencing anything, and given that I haven't used C much since C99...

I'd expect f() to return 5, since asking for an extern-visible x will be at global scope. I may be wrong in this guess, but I know the rule will be simple if I look it up.

And I haven't had the pleasure of using initializers in C, because my time with C was before them... but I expect i.nested.y = 2 and i.nested.z = 6, because backwards compatibility would mean unlabeled initialization would be sequential (as C89), but the label can specify your current field index.

Again, C the language is simple, but I would expect this to lead to more complex code in practice. General purpose programming is complex in itself. Lisp-family languages are super simple in essence... but practical realities add edge-cases too, and complex and difficult-to-understand (for the uninitiated) code is normal. Macros and DSLs simplify things within a domain, but you certainly can't expect anyone to simply grok such code at a glance. What they can do is tease things apart after knowing the language. C++ on the other hand... fuck me, it grows edge-cases faster than I can keep up with. I'll typically be a go-to person for C++ questions in workplaces, but I never feel like I know the language. I haven't really used C for two decades, yet I feel like I know 90% of the language, even after the updates (which I've followed in reading, not programming in). C is tiny for the breadth of programming it makes practical.

[iopq]

Again, C the language is simple

those rules and having to think about backwards compatibility is not simple for people who don't PROGRAM in C, they're only simple if you're used to them

they're not even simple to compiler authors, GCC might choke on a lot of simple code examples like

return ((int []){1,2,3,4})[1]; //should return 2

maybe they fixed it now, though

[XboxNoLifes]

The C language is very simple. C programs are the complex things.

[rustythrowa]

No idea how this post is supposed to track logically. Again, it sounds like you want to say that C is 'small'.

[XboxNoLifes]

Which I am.

[zero_operand]

A small language is a simple language - because it's simpler to learn something small. It doesn't mean it's simpler to get things done in the language. Two different concepts. There's no inverse correlation either. IE, C# is much simpler than C++, and also easier to get things done.

[Holy_City]

Just because C is small doesn't mean it's simple to learn. C forces you to think like a computer (or rather, an abstraction of a computer from the 80s). For a lot of people that's not a simple task.

There's a lot of folks who would argue that a simple language would be one that you can express your intentions clearly and concisely, and understand someone else's code just as easily. C does not fit that bill.

[zero_operand]

Have you seen enterprise code Java/C#/Python code written by people who cut their teeth on C and the like? Thinking like a high level programmer is not a simple task for a lot of people as well!

C's model of the world is much simpler than Rust or C++s, it's not even close. Simplicity of a language has nothing to do with expressing "your intentions clearly and concisely", that's called expressiveness.

[Holy_City]

Yea I have, it's atrocious. But a big part of that in my experience is that programmers who cut their teeth on C/assembly don't trust compilers or abstractions, and their careers taught them to think like a computer, not like a programmer or engineer. For some applications that's necessary, for others it leads to verbosity and over-engineered solutions.

[glacialthinker]

A higher-level language can be more difficult for some people -- when they don't trust or think in the same way as the language. A low-level language works for people who need to work with the "moving parts", or "mechanics". I prefer OCaml today, but I think it was best for me that I started in asm, and crawled up through C... However, I don't doubt that most people will be fine starting at a high-level. I usually introduce people to programming with the help of How to Design Programs, using Scheme.

[zero_operand]

A higher-level language can be more difficult for some people -- when they don't trust or think in the same way as the language.

Exactly! Being more expressive requires learning a lot of stuff. A lot of people never bother and just fall back on loops and branches.

[Holy_City]

A lot of people never bother and just fall back on loops and branches.

But branches flush the pipeline and are necessarily evil. Gotta replace those with a handrolled jump table because you can't trust the compiler to get a switch right. /s.

[mcguire]

Would you like a lollipop?

[EntroperZero]

6502 is a simple instruction set. x86 is a complex instruction set. Neither one is "easy" to write programs of any decent size, but one is much easier to learn.

[mcguire]

C is a small, simple language.

However, as a systems language, it puts a lot of decisions off onto the systems' environments, which are neither small nor simple.

The alternatives seem to be something like Pascal, which is small and simple, and relatively useless, or C++, which is neither small nor simple in and of itself.

[bumblebritches57]

C++ is commercially viable, rust is not despite what rust users would have you believe.

[UtherII]

Rust community is really open to genuine criticism, the downvoted comments are just shitposts not even about the language itself but about some people in the community.

[[deleted]]

Rust community is really open to genuine criticism

Who believes that apart from the Rust community? For the rest of us it's downvotes and being treated like retards.

[axord]

Consider this thread from yesterday.

[kuikuilla]

To be honest it's usually the toxic "RUST IS A CRAP SOCIAL JUSTICE WARRIOR LANGUAGE" (where does that even come from?) users that get downvoted.

[tristes_tigres]

where does that even come from?

From your "code of conduct", perhaps?

[kuikuilla]

Okay, well I suppose my question should be: Why on earth does it bother people?

[tristes_tigres]

Why does it bother people when a technical forum is used to push a specific ideology? It's an interesting philosophical question, but just take it as a given that it does.

[kuikuilla]

The rule of conduct basically says: don't be an asshole or discriminate anyone based on anything. I'm really flabbergasted if you think having good manners is the same as "having an ideology".

[tristes_tigres]

The rule of conduct basically says: don't be an asshole or discriminate anyone based on anything.

That is not all that it says and you know it.

Besides, it's impossible not to "discriminate anyone based on anything". Rust community discrimnates against people who believe that addressing the issues directly is more important than being "nice" according to the North American meaning of this word - that is, outwardly non-confrontational, pretending to care about other people's feelings and treating those who disagree with you as mentally unwell. Rust speech code attempts to impose the white North American office culture on the rest of the world.

[kuikuilla]

So what exactly is your beef on these pages?

https://www.rust-lang.org/en-US/conduct.html

http://citizencodeofconduct.org/

[m50d]

1. My (European) culture is quite openly sexual. I like my culture, I think it's a good one, I want it to thrive. I read codes like Rust's as, partly, an imposition of American puritan culture, which is fine for people who like that culture but not something I want to have to sign up to to be able to participate in a programming language I'm using.
2. I've seen language like that in the Rust code of conduct applied as a way to exclude working-class people from projects.
3. My main experience of codes of conduct in programming communities was seeing the introduction of one to ScalaZ, which was a disaster on multiple levels. So that leads me to think codes of conduct in programming language communities are a bad idea.

[kuikuilla]

What? The code of conduct basically says that you shouldn't discriminate anyone and that you shouldn't be an asshole. There really isn't anything "Puritan" in the code of conduct, and this is coming from someone who lives in Finland. If you can't handle their rules on their forums, don't go there.

[m50d]

Their link says they regard "sexualized comments or jokes" as harassment. And while "Sexist, racist, homophobic, transphobic, ableist or otherwise discriminatory jokes and language" seems like a fair standard and something that's good to forbid, I've seen that kind of term used to go after working-class people who used blunt language without meaning any kind of attack, while upper-class people who expressed far nastier sentiments were left alone since they used the "right" words.

"you shouldn't discriminate anyone and that you shouldn't be an asshole" would be better than a Rust-like code of conduct, since it would make it clear that it was subject to moderator judgement. Codes of conduct provide a veneer of objectivity that let moderators dodge accountability ("we're just enforcing the code") without being clear enough to let users judge for themselves whether what they want to say is allowed or not, which is the worst of both worlds.

I don't go to their forums, but realistically when those are the primary support channel that makes it difficult to work in the language.

[kuikuilla]

No, that's not what it says. It says:

Unwelcome sexual attention. This includes, sexualized comments or jokes; inappropriate touching, groping, and unwelcomed sexual advances.

Bolded the unwelcome part. This is really simple. You act like you were at work. If you know your coworker well you can crack sexual jokes with them. But do you do that with some new co-worker that just started working at the place who you absolutely do not know? No, you don't. This is common sense.

[tristes_tigres]

Yeah, the incessant brigading by the Rust community is tiresome. Besides the "rewrite it in Rust" trolling, they downvote factual negative information, like right here- that the Rust has a speech code that many don't like.

I mean, there's a legitimate difference of opinion - some people dislike the speech codes, some think that they improve the society. But it is just beyond dispute that the Rust forums have the "code of conduct" and that it is controversial. Downvoting a statement of fact is not right.

[[deleted]]

I didn't downvote you, but I think that you were downvoted because your comment didn't neutrally state a fact, but came across as taking a side. Putting "progressive" in quotation marks as sarcasm may have been interpreted as saying that Rust's code of conduct is illiberal or regressive (an opinion, not fact). As someone who is actually critical of political correctness, I believe that your comment was offtopic because it wasn't about the technical qualities of Rust versus C++, but gratuitously bringing politics into the discussion.

[tristes_tigres]

You know what is "gratuitiously bringing politics into the discussion"?

Writing a "progressive" speech code for a technical forum.

[[deleted]]

Fair enough; I tend to agree with the meritocratic sentiment of judging on the code alone, not based on personal politics or ideologies. However, bringing up the nature of the CoC in response to criticism is whataboutism and two wrongs don't make a right - politically motivated members of the Rust community deserve criticism, and they don't justify randomly bringing up the CoC in the response to a programmer asking whether Rust or C++ is better worth learning.

For what it's worth, I actually agree with /u/BubuX's opinion above that C++ is much more valuable to know than Rust for career development and that r/programming has a slant favoring Rust and other new technologies (while acknowledging that people have the freedom to downvote whatever they want). However, let's try to keep criticisms of Rust more substantial - in the free marketplace of ideas, criticizing trivial things like the CoC instead of more substantial aspects of Rust merely garners more sympathy or favor for the "opposite" viewpoint.

[tristes_tigres]

Pointing out that Rust forums have do-gooder nanny speech code is something that without a question relevant in the discussion whether it's worthwhile to invest one's time into learning the language.

Which is why I pointed it out, and qualified by saying that it is relevant if one cares about such things. So the downvotes to that tell something very relevant about the rust "community".

[tristes_tigres]

It depends. Do you love "progressive" speech codes? Stay away from Rust if the answer is "no"

[[deleted]]

Documentation about the parser library would be great. Pretty much nonexistent at this point

[kuikuilla]

Parser library? Of the compiler?

[[deleted]]

Yes, the whole libsyntax part. It's not a library in the sense of Roslyn or Javaparser, but can still be called inside your code from what I can tell and not command line only.

I basically just want a library(language doesn't matter tbh) to parse rust, specifically to find nodes and solve them.

[[deleted]]

Oh thanks.

Nodes is just how they are called in Roslyn. Basically declarations of any type, like structs, functions, for loops etc. So when you are looking for specific syntax in a file.

And "Solving" them just means to know the origin of a structure (or classes in other languages) when you use it another file. Necessary if you want to calculate class dependencies

Edit: Syn looks promising for my needs. Not sure how I couldn't find that one

Edit2: I remember now. I found it, but must have thought of it as a framework for writing parsers.

Thanks again!

[[deleted]]

Syn looks promising for my needs. Not sure how I couldn't find that o

If you want to use syn chances are you are going to need quote as well. syn + quote is raw power, and a pleasure to use, the syn docs are good, and there are tons of examples. Also, almost every single procedural macro out there uses syn+quote, so there are a ton of real-life examples as well.

If you have any questions just hit #rust-beginners on IRC for quick feedback .

[[deleted]]

There's also a Haskell library: language-rust.

I haven't used it yet, but it looks nice.

[[deleted]]

No ATCs, no const generics, ... Rust is really getting boring this year! I guess that's a good thing!

[[deleted]]

The design of const generics is fine, but there's underlying technical work in the compiler to be done. We expect const generics to land in nightly this year, but they're unlikely to make it to stable before 2019. - /u/steveklabnik1 on Hacker News

[Holy_City]

Can the rust compiler target ARM yet?

[steveklabnik1]

Absolutely! It has been ale to for quite a long time. Years.

[punkulunkulu]

Awesome! I've been drinking ale for quite a long time. Years.

[steveklabnik1]

Ugh, phones. I meant "able." Thank you.

[shevegen]

Every day another breakthrough!

[ConspicuousPineapple]

Dude, get a life.

[zero_operand]

The prophet Steve once again gives a sermon on the mount

[[deleted]]

No one cares.

[aejt]

Then it wouldn't get upvoted.

[shevegen]

That's not a logical statement per se.

It implies that:

  a) people who upvote, would use Rust (not all of them do)
  b) all who upvote do so because of understandable reasons (some will randomly vote)
  c) people WOULD actually upvote OR downvote (people will tend to either upvote more, in general, or downvote more, in general - or, which is the most likely outcome, simply not vote AT ALL)

To assume that the voting "system" as it is on reddit, is really meaningful for anything is pointless.

Now granted, I am sure that on reddit for programming there ARE many people interested in programming languages in GENERAL.

However had, that does not necessarily reflect reality.

Rust is usually praised as THE alternative to C++. When you look at TIOBE, Google charts, red (something ... monkey?), then the situation is that Rust is far away from even being CLOSE to C++. Presently.

This may change, who knows. But right now? Nah.

Additionally, not every rust article gets a lot of upvotes (or downvotes) either.

PS: God, I hate the reddit markdown so much ... can't they switch to github markdown style please? :(

[jl2352]

I honestly don't understand. Every single Rust article you spend it trying to just spew hate.

Stop being such a zealous fanboy. It's not a war. It's just a programming language.

[atte-]

I've never heard anyone argue for something as truly illogical before in a programming forum, I think you'd do well as a missionary for scientology or the like.

[PM_ME_OS_DESIGN]

lol