Hello all, and welcome back to Advent of Code 2020, featuring Cool Bear.

Hey y’all!

Let’s get right to it.

The problem statement for Day 3 is as follows: we’re given a map, that looks like this:

..##....... #...#...#.. .#....#..#. ..#.#...#.# .#...##..#. ..#.##..... .#.#.#....# .#........# #.##...#... #...##....# .#..#...#.#

And we imagine that it repeats infinitely to the right, like so:

In part 1, we’ve looked at three executables:

• sample, an assembly program that prints “hi there” using the write system call.
• entry_point, a C program that prints the address of main using printf
• The /bin/true executable, probably also a C program (because it’s part of GNU coreutils), and which just exits with code 0.

We noticed that when running entry_point through GDB, it always printed the same address. But when we ran it directly, it printed a different address on every run.

A couple months ago I made a loudness meter and went way too in-depth into how humans have measured loudness over time.

Today we’re looking at a spectrogram visualization I made, which is a lot more entertaining!

We’re going to talk about how to extract frequencies from sound waves, but also how my spectrogram app is assembled from different Rust crates, how it handles audio and graphics threads, how it draws the spectrogram etc.

My honeymoon with the Go language is extremely over.

This article is going to have a different tone from what I’ve been posting the past year - it’s a proper rant. And I always feel bad writing those, because, inevitably, it discusses things a lot of people have been working very hard on.

In spite of that, here we are.

Having invested thousands of hours into the language, and implemented several critical (to my employer) pieces of infrastructure with it, I wish I hadn’t.

I have obsessed about this long enough, I think it’s only fair I (and you!) get some content out of it.

When I started writing this article, I was working on my P99 CONF slides. Those slides happen to include some bits of code. And because I’m a perfectionist, I would like this code to be syntax highlighted, like this:

let addr: SocketAddr = config? ln = addr? config

The year is drawing to a close, and I’m going off on a much-needed holiday next week. This seems like a good time to look back at the past twelve months!

I can’t believe that shipped

2018 was the year of foundational work. As far as “work work” is concerned, I spent the first 9 months finishing up my largest project ever, the itch v25 rewrite.

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:

Some bugs are merely fun. Others are simply delicious!

Today’s pick is the latter.

Reproducing the issue, part 1

(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:

I was not planning on doing anything specific this December, but a lot of folks around me (on Twitter, at work) have chosen this Advent of Code to pick up Rust, and I’ve got big FOMO energy, so, let’s see where this goes.

I’ll be doing all of these on Linux, so there may be some command-line tools involved, but don’t worry about them - the code itself should run on all platforms no problem.