It feels like an eternity since I’ve started using Rust, and yet I remember vividly what it felt like to bang my head against the borrow checker for the first few times.

I’m definitely not alone in that, and there’s been quite a few articles on the subject! But I want to take some time to present the borrow checker from the perspective of its benefits, rather than as an opponent to fend with.

Hello and welcome to Part 11 of this series, wherein we finally use some of the code I prototyped way back when I was planning this series.

Where are we standing?

Let’s review the progress we’ve made in the first 10 parts: first, we’ve started thinking about what it takes for computers to communicate. Then, we’ve followed a rough outline of the various standards and protocols that have emerged since the 1970s.

It’s refactor time!

Our complete program is now about a hundred lines, counting blank lines (see the end of part 3 for a complete listing).

While this is pretty good for a zero-dependency project (save for pretty-hex), we can do better.

First off, concerns are mixed up. In the same file, we:

• Expose LoadLibraryA / GetProcAddress
• Expose the Win32 ICMP API

In the previous article, I gave brummi a go. However, we’ve seen that it still doesn’t fit our requirements: we need a tool that’s fast, easy to install and configure, produces beautiful and usable docs.

Yesterday I started building my own documentation generator, and in this series I’ll present the challenges I face and how I solved them. This might show a few ooc tricks, perhaps some software design, some good, some bad, but overall I hope it’ll be a good read!

Intro

When I started my Patreon, I had no idea if it would work at all. The whole thing seemed like a gamble: spend an inordinate amount of time writing quality articles, and hope that folks will like it enough to kick in 5, 10, or 50 bucks a month just to see more of them.

I’m happy to say the gamble paid off - literally. Take that, impostor syndrome!

I have long been at war against Rust compile times.

Part of the solution for me was to buy my way into Apple Silicon dreamland, where builds are, like… faster. I remember every time I SSH into an x86_64 server, even the nice 64-core ones.

And another part was, of course, to get dirty with Rust itself.

I wrote Why is my Rust build so slow?, which goes in-depth into rust build performance, down to rustc self-profiling even!

Up until recently, hyper was my favorite Rust HTTP framework. It’s low-level, but that gives you a lot of control over what happens.

Here’s what a sample hyper application would look like:

$ cargo new nostalgia Created binary (application) `nostalgia` package

$ cd nostalgia $ cargo add hyper@0.14 --features "http1 tcp server" Updating 'https://github.com/rust-lang/crates.io-index' index Adding hyper v0.14 to dependencies with features: ["http1", "tcp", "server"] $ cargo add tokio@1 --features "full" Updating 'https://github.com/rust-lang/crates.io-index' index Adding tokio v1 to dependencies with features: ["full"]

Part 1

Let’s tackle the day 4 challenge!

In this one, we get an input like this:

2-4,6-8 2-3,4-5 5-7,7-9 2-8,3-7 6-6,4-6 2-6,4-8

Each line has two ranges: the first line has ranges containing 2, 3, 4, and 6, 7, 8. We must count how many pairs have ranges where one fully contains the other.

In Rust, we can express this with “inclusive ranges” (std::ops::RangeInclusive), and those implement Iterator, so we can do:

We’ve just spent a lot of time abstracting over LoadLibrary, but we still have all the gory details of the Win32 ICMP API straight in our main.rs file! That won’t do.

This time will be much quicker, since we already learned about carefully designing an API, hiding the low-level bits and so on.

Let’s add an icmp module to our program. Actually, we’ve been dealing with an IPAddr all this time, it also sounds like it could use its own package: