I often give bits and pieces of advice on how to build Rust stuff the comfy way. But it can be hard to see how everything comes together, especially when it comes to, say, deploying a web service in production.

So, let's start from the very beginning (setting up a Linux VM), and march together towards the objective: a production-grade Rust web service, built with Nix.

Some bugs are merely fun. Others are simply delicious!

Today's pick is the latter.

(It may be tempting to skip that section, but reproducing an issue is an important part of figuring it out, so.)

I've never used Emacs before, so let's install it. I do most of my computing on an era-appropriate Ubuntu, today it's Ubuntu 22.10, so I just need to:

This time around, we're porting a solution from C++ to Rust and seeing how it feels, how it performs, and what we can learn about both languages by doing that.

See Day 17 for the rationale re: porting solutions rather than writing my own from scratch. TL;DR is: it's better than nothing, and we can still focus about learning Rust rather than spending entire days fighting off-by-one errors.

Advent of Code gets harder and harder, and I'm not getting any smarter. Or any more free time. So, in order to close out this series anyway, I'm going to try and port other people's solutions from "language X" to Rust. That way, they already figured out the hard stuff, and we can just focus on the Rust bits!

Sounds good? Good. Let's proceed.

Let's tackle the day 16 puzzle!

The input looks like this:

Valve AA has flow rate=0; tunnels lead to valves DD, II, BB
Valve BB has flow rate=13; tunnels lead to valves CC, AA
Valve CC has flow rate=2; tunnels lead to valves DD, BB
Valve DD has flow rate=20; tunnels lead to valves CC, AA, EE
Valve EE has flow rate=3; tunnels lead to valves FF, DD
Valve FF has flow rate=0; tunnels lead to valves EE, GG
Valve GG has flow rate=0; tunnels lead to valves FF, HH
Valve HH has flow rate=22; tunnel leads to valve GG
Valve II has flow rate=0; tunnels lead to valves AA, JJ
Valve JJ has flow rate=21; tunnel leads to valve II

The day 15 puzzle falls into the "math puzzle" territory more than "let's learn something new about Rust", but since several folks asked if I was going to continue... let's continue.

The sample input is as follows:

Sensor at x=2, y=18: closest beacon is at x=-2, y=15
Sensor at x=9, y=16: closest beacon is at x=10, y=16
Sensor at x=13, y=2: closest beacon is at x=15, y=3
Sensor at x=12, y=14: closest beacon is at x=10, y=16
Sensor at x=10, y=20: closest beacon is at x=10, y=16
Sensor at x=14, y=17: closest beacon is at x=10, y=16
Sensor at x=8, y=7: closest beacon is at x=2, y=10
Sensor at x=2, y=0: closest beacon is at x=2, y=10
Sensor at x=0, y=11: closest beacon is at x=2, y=10
Sensor at x=20, y=14: closest beacon is at x=25, y=17
Sensor at x=17, y=20: closest beacon is at x=21, y=22
Sensor at x=16, y=7: closest beacon is at x=15, y=3
Sensor at x=14, y=3: closest beacon is at x=15, y=3
Sensor at x=20, y=1: closest beacon is at x=15, y=3

I like how the day 14 puzzle sounds, because I think it'll give me an opportunity to show off yet another way to have Rust embedded in a web page.

But first...

Let me guess: parsing?

You bet your furry ass, parsing.

The input looks something like this:

498,4 -> 498,6 -> 496,6
503,4 -> 502,4 -> 502,9 -> 494,9

And each line is essentially... a polyline: we're supposed to draw lines between every point on the path, and that determines rocks on the map.

The day 13 puzzle needs a speech therapist.

???

...because it has an awful lisp!! Ahhhahahahhhh

Are you ok? What is.. what is going on with you?

No but seriously we have what are ostensibly S-expressions, except they use JSON-adjacent notation:

[1,1,3,1,1]
[1,1,5,1,1]

[[1],[2,3,4]]
[[1],4]

[9]
[[8,7,6]]

[[4,4],4,4]
[[4,4],4,4,4]

[7,7,7,7]
[7,7,7]

[]
[3]

[[[]]]
[[]]

[1,[2,[3,[4,[5,6,7]]]],8,9]
[1,[2,[3,[4,[5,6,0]]]],8,9]