Here’s my late #rust2018 post. I contribute code to a lot of projects in a lot of different languages. I think it’s really important not to think about Rust in isolation, but in the context of the greater open source world. Here area few specific ways I think about this:

ease of contributing to projects in rust

interoperability with other languages (both directions)

ripgrep should be in debian

don’t fracture the ecosystem

The rest of this post is going through these in turn.

Rust projects should be easy to contribute to

I make a fair number of open source contributions, whether to fix small bugs, or scratch an itch. Sometimes the projects are in languages I don’t know well, or even at all. As a casual contributor, I want to be able to get in and make my change with as little incidental difficulty and frustration as possible.

But it doesn’t always work like that. The language a project is written in is a huge factor in how easy or hard it is.

My biggest wish for Rust in 2018 is that I would like to feel free to write programs in Rust without worrying that I’m excluding people from contributing.

I see a few ways that choice of language can affect who can contribute code changes, and how easily:

readability

writability

community coding style

tooling

Readability

To make a code change, you need to understand what the code is doing. The language itself plays a big part. For example, Python code is very easy to read, and Go is almost comically easy to read. It’s great!

Rust is doing ok here, but there’s room for improvement. The ergonomics work from 2017 will make a huge difference. It just needs to land! In particular, impl Trait and argument lifetimes will cut down on a huge amount of angle bracket noise, and match default bindings will get rid of most uses of the ref keyword, which doesn’t come up anywhere else in the language.

A core focus of 2017 was ergonomics and I don’t want that to go away. Rust should keep pushing on this throughout 2018, and beyond.

Writability

If you’re making a small code contribution to a program you use, often you get started by copy-paste-modify. Ideally the language doesn’t make that too hard. This is another place where ergonomics are important. Ownership and borrowing make this inherently harder than in other languages: I don’t know any other languages where

foo(x); foo(x);

can be a compiler error!

The compiler messages keep getting better, and this really does make a difference.

Going beyond copy-paste-modify coding, Rust’s syntax has a fair number of gotchas. Luckily there’s a bunch of ergonomics improvements that should land soon. Even as a fairly experienced Rust programmer, I find the “how much &*[..] random noise do I need to add to make a thing work?” thing annoying. I’m really thankful for the effort that’s being poured into this.

I can’t wait to be able to stop saying to people, ‘I know it’s bad, but it’s being worked on’, and start saying ‘have you tried 1.28? All that nonsense is gone now!’

Community coding style

The kind of code that a language community prefers to write also makes a huge difference. There was a project I wanted to make a change to, and it happened to be written in Scala. The community coding style there is heavily slanted towards highly generic code, even when solving a very specific and concrete problem. I found it to be enough of an impediment that I never contributed.

Rust’s expressive type system is responsible for so much of for so much of how Rust can be low level and high level at the same time. Luckily it’s not quite expressive enough yet to allow monads to enter normal discourse. :-)

Most of the Rust projects whose code I’ve looked at have shied away from complicating things via incidental cleverness. I want the community to keep writing readable-if-verbose code as the type system learns more tricks.

Tooling

It should be dead simple to clone a project, build it, run its tests, and modify its dependencies.

Rust is doing a fantastic job of this: cargo is pretty damned amazing. I’m struggling to think of a crate I’ve worked that didn’t use the default cargo workflow for building, testing, and dependency management.

If you compare the experience to Go, it’s really striking. I actually feel dumb every time I try to contribute to a Go program. I’m sure that if you’re writing Go regularly, GOPATH and the seemingly random mishmash of plain go build , Makefiles, and other stuff are all easy to deal with. I’m usually trying to get in and make a small change, and move on. All that non-uniformity is a borderline showstopper. And that’s not even thinking about needing to modify dependencies! (Incidentally, I’m really excited to see Go making improvements here this year!)

If I had to pick one place I’d like to see get better, it’d be in finding the right crate for the job among all the ones that are out there. The crates.io search is not really all that great. I know that this is being worked on, and I’m excited to see what this looks like in a few months.

Interoperate well with other languages

Rust’s lack of a runtime is a huge strength. It can call into C without worrying about a GIL, or pinning threads or memory, or anything like that. And other languages can call into Rust just as easily as into C.

I want to see Rust really take advantage of this. Let’s avoid rewriting the world in pure Rust, and instead make using existing C and C++ libraries way easier. I’d like to see something like the Rust API guidelines, but focused on FFI wrapping libraries and the question of how to best turn a C API into an ergonomic and idiomatic Rust one. I want there to be a well-supported way of handling C dependencies, including being easily able to depend on system versions.

In the other direction, there are some really interesting projects out there focused on making it easy to write native extensions in Rust. Here I’m thinking of things like Helix for Ruby, Neon for node. It’s just magical that this is possible:

#[macro_use] | $ irb extern crate helix; | >> require "console" | >> Console.log("I'm in your Rust") ruby! { | LOG: "I'm in your Rust" class Console { | def log(string: &str) { | println!("LOG: {:?}", string); | } | } | } |

Rust has a lot to offer as a safe way to enter the world native extensions, whether for performance, low level capabilities, or just fun. I’d love to see these projects get more attention!

ripgrep should be in Debian

Or your favourite non-bleeding-edge distro. This sounds simple but it’s not. There’s a lot of work in working out to fit Rust into the Debian packaging rules. I think a lot of the policy work is done, but the tooling isn’t quite at the point where ripgrep and all its dependencies can be packaged. The six week release cycle that allows Rust to get better so quickly also works against this. As an example, the Firefox nightly PPA I use has had a failing build for the last week because Firefox now needs Rust 1.23.0 to build. I have no idea how to reconcile the Rust release cycle with the annual or semiannual release cycle many distros have, but it’s something the community must figure out.

Don’t fracture the ecosystem

The Rust async story is coming along nicely. But the community needs to take care not to split the crate ecosystem up unnecessarily. For example, historically Python had Twisted and Tornado that were two quite separate worlds with a lot of duplicated functionality. And in Scala, there’s the world of Twitter futures, the world of standard library Futures, and the world of akka. I think Rust is not at too much risk, but it’s something I worry about a bit.

Closing

I think a great way to judge how Rust is doing is to see there be more programs in Rust that aren’t about Rust. ripgrep is an inspiring example of taking the power of Rust, and making a difference to a much wider audience. It’s even included by default in at least a couple of text editors!

I’d love to see more of this in 2018.