At FP Complete, we have long spoken about the three pillars of a software development language: productivity, robustness, and performance. Often times, these three pillars are in conflict with each other, or at least appear to be. Getting to market quickly (productivity) often involves skimping on quality assurance (robustness), or writing inefficient code (performance). Or you can write simple code which is easy to test and validate (productivity and robustness), but end up with a slow algorithm (performance). Optimizing the code takes time and may introduce new bugs.
For the entire history of our company, our contention has been that while some level of trade-off here is inevitable, we can leverage better tools, languages, and methodologies to improve our standing on all of these pillars. We initially focused on Haskell, a functional programming language that uses a strong type system and offers decent performance. We still love and continue to use Haskell. However, realizing that code was only half the battle, we then began adopting DevOps methodologies and tools.
We've watched with great interest as the Rust programming language has developed, matured, and been adopted in industry. Virtually all major technology companies are now putting significant effort behind Rust. Most recently, Microsoft has been quite publicly embracing Rust.
In this post, I wanted to share some thoughts on why we're thrilled to see Rust's adoption in industry, what we're using Rust for at FP Complete, and give some advice to interested companies in how they can begin adopting this language.
We're big believers in using the computer itself to help us write better code. Some of this can be done with methodologies like test-driven development (TDD). But there are two weak links in the chain of techniques like TDD:
- It requires active effort to think through what needs to be tested
- It's possible to ignore these test failures and ship broken code
The latter might sound contrived, but we've seen it happen in industry. The limitations of testing are well known, and we've previously blogged about recommended testing strategies. And don't get me wrong: testing is an absolutely vital part of software development, and you should be doing more of it!
But industry experience has shown us that many bugs slip through testing. Perhaps the most common and dangerous class of bug is memory safety issues. These include buffer overruns, use-after-free and double-free. What is especially worrying about these classes of bugs is that, typically, the best case scenario is your program crashing. Worst case scenario includes major security and privacy breaches.
The industry standard approach has been to bypass these bugs by using managed languages. Managed languages bypass explicit memory management and instead rely on garbage collection. This introduces some downsides, latency being the biggest one. Typically, garbage collected languages are more memory hungry as well. This is the typical efficiency-vs-correctness trade-off mentioned above. We've been quite happy to make that trade-off ourselves, using languages like Haskell and accepting some level of performance hit.
Rust took a different approach, one we admire deeply. By introducing concepts around ownership and borrowing, Rust seeks to drastically reduce the presence of memory safety errors, without introducing the overhead of garbage collection. This fits completely with FP Complete's mindset of using better tools when possible.
The downside to this is complexity. Understanding ownership can be a challenge. But see below for information on how to get started with Rust. This is an area where FP Complete as a company, and I personally, have taken a lot of interest.
Going beyond memory safety issues, however, is the rest of the Rust language design. As a relatively new language, Rust has the opportunity to learn from many other languages on the market already. And in our opinion, it has selected some of the best features available from other languages, especially our beloved Haskell. Some of these features include:
- Strong typing
- Sum types (aka enums) and pattern matching
- Explicit error handling, but with a beautiful syntax
- Async syntax
- Functional style via closures and
In other words: Rust has fully embraced the concepts of using better approaches to solve problems, and to steal great ideas that have been tried and tested. We believe Rust has the potential to drastically improve software quality in the world, and lead to more maintainable solutions. We think Rust can be instrumental in solving the global software crisis.
Rust at FP Complete
We've taken a three-pronged approach to Rust at FP Complete until now. This has included:
- Producing educational material for both internal and external audiences
- Using Rust for internal tooling
- Writing product code with Rust
The primary educational offering we've created is our Rust Crash Course, which we'll provide at the end of this post. This course has been honed to address the most common pitfalls we've seen developers hit when onboarding with Rust.
Also, as a personal project, I decided to see if Rust could be taught as a first programming language, and I think it can.
For internal tooling and product code, we always have the debate: should we use Rust or Haskell. We've been giving our engineers more freedom to make that decision themselves in the past year. Personally, I'm still more comfortable with Haskell, which isn't really surprising: I've been using Haskell professionally longer than Rust has existed. But the progress we're seeing in Rust—both in the library ecosystem and the language itself—means that Rust becomes more competitive on an almost monthly basis.
At this point, we have some specific times when Rust is a clear winner:
- When performance is critical, we prefer Rust. Haskell is usually fast enough, but microoptimizing Haskell code ends up taking more time than writing it in Rust.
- For client-side code (e.g., command line tooling) we've been leaning towards Rust. Overall, it has better cross-OS support than Haskell.
- There are some domains that have much better library coverage in Rust than in Haskell, and then we'll gravitate towards them. (The same applies in the other direction too.)
- And as we're engineers who like playing with shiny tools, if someone wants to have extra fun, Rust is usually it. In most places in the world, Haskell would probably be considered the shiny toy. FP Complete is pretty exceptional there.
We're beginning to expand to a fourth area of Rust at FP Complete: consulting services. The market for Rust has been steadily growing over the past few years. We believe at this point Rust is ready for much broader adoption, and we're eager to help companies adopt this wonderful language. If you're interested in learning more, please contact our consulting team for more information.
How do you get started with a language like Rust? Fortunately, the tooling and documentation for Rust is top notch. We can strongly recommend checking out the Rust homepage for guidance on installing Rust and getting started. The freely available Rust book is great too, covering many aspects of the language.
That said, my recommendation is to check out our Rust Crash Course eBook (linked below). We've tried to focus this book on answering the most common questions about Rust first, and get you up and running quickly.
If you're interested in getting your team started with Rust, you may also want to reach out to us for information on our training programs.
Want to read more about Rust? Check out the FP Complete Rust homepage.
Want to learn more about FP Complete offerings? Please reach out to us any time.
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