Certainty by Construction Progress Report 4

The following is a progress report for Certainty by Construction, a new book I’m writing on learning and effectively wielding Agda. Writing a book is a tedious and demoralizing process, so if this is the sort of thing you’re excited about, please do let me know!

I landed a two-week long gig three weeks ago, and that ate up my time for a little bit. But I’m back in action, significantly richer, and much more inspired to be working on Certainty by Construction again.

The end is finally in sight. This week I tore apart the modular arithmetic stuff from the material on setoids, realizing that the two were unrelated. I’d been having a lot of trouble getting that chapter sorted out, and it’s because it shouldn’t have been a chapter after all.

Instead, I’ve been working on merging the stuff about monoids and monoid homomorphisms into the setoid chapter, which is a much better motivation for setoids when you realize you can’t write many of the monoids you’d like to be able to. If I can fit lattices into there as well, I’ll be a very happy man.

Also this week I worked on some typesetting things. In particular, you’ll notice a gutter indicator on every code block telling you exactly where the code block should be indented relative to the file. This is a big improvement from before when you just had to guess, but I’m not yet happy with it. Please give it a read and let me know if you like the change, or what might be better.

Additionally I spent a lot of time making sure every code block had good vertical alignment of its code elements. That means all the equals signs should line up, and that the same argument is always in the same column, no matter how many patterns you’ve already matched. It’s not the sort of thing you’d notice, but it’s certainly the sort of thing whose absence you’d notice.

I’m committing to a hard deadline for this book of September 1, 2023. The thing is going to be finished and off to the printers by that day, because I want to have it done before I’m married, and that is coming up soon. And also, I work much better with a deadline.

Anyway, that’s all for today. If you’ve already bought the book, you can get the updates for free on Leanpub. If you haven’t, might I suggest doing so? Your early support and feedback helps inspire me and ensure the book is as good as it can possibly be.