Benoit Daloze of TruffleRuby points out that this is all much easier to read if you define your Ruby internals in Ruby, like they do. He's not wrong.

The easiest and simplest way to get out of a reading slump or to get into reading in the first place is to begin small. Novellas offer (almost) the sumptuousness and holisticness of novels. But they also don’t strain the mind too much because they are quick reads. Here are 10 short and easy to read books that will help beginners start reading. This list of novellas and short novels that are easy to slip into, not just because of their length but also because of the style of writing itself.

It might be worth moving the latest updates to the top of this answer. I had to go through the whole thing to get to the best answer, flexbox.

Svelte looks pretty similar, but has two small changes that personally make the Svelte code easier to read, in my opinion:

It is much easier to track what is going on within the activity. Instead of transporting additional state via ctx, you expose the outcome via an additional end event.

So why the over-complication? What we got now is replicating a chain of && in the former version. This time, however, you will know which condition failed and what went in by using tracing. Look at the trace above - it’s impossible to not understand what was going on.

“Make it right” means that the code is maintainable and easy to change. Humans can read it, not just computers. New engineers can easily add functionality to the code. When there’s a defect, it is easy to isolate and correct.