Denis Defreyne

Weeknotes 2025 W43: Pull down

October 20​–​26, 2025

Shower thoughts:

  • The casting of Star Trek: Deep Space 9 is impressive, even before you realize that literally every single character is played by Jeffrey Combs.

  • MCP still means master control program to me.

A good amount of time was spent this week on replacing the use of kramdown on my web site with pulldown-cmark.

First of all, pulldown-cmark is considerably faster than kramdown. Not too much of a surprise, given that pulldown-cmark is implemented in Rust and kramdown is implemented in Ruby.

With pulldown-cmark, I can have a Markdown implementation that I can reuse in my Zig static-site generator too — kramdown is not quite usable from anything but Ruby.1

pulldown-cmark is extensible, too. I need support for footnotes, math, and strike-through. Also, pulldown-cmark adheres to the CommonMark standard, and adds extensions in a backwards-compatible way.

So yes, I have been writing Rust, Zig, and Ruby lately. What a mixture! All three are used for my web site now.

The difference between all the Markdown dialects is frustrating. I’ve got a FFI-powered Nanoc filter for pulldown-cmark, but the filter has needed a lot of customization to make it spit out something that isn’t too dissimilar from what kramdown spits out. I have tooling to diff the HTML output, but it still took quite a while to find all the differences and fix them.

For example, in kramdown, an unordered list can use any type of bullet. This is a single unordered list:

- foo
- bar
* qux

In pulldown-cmark, however, those are two lists: foo and bar form one list, and qux forms another. Quite some content on my web site is — accidentally! — written in a way that uses multiple list styles, so I’ve opted to simply preprocess the input to unify the list styles:

content = content.gsub(
  /^\*(\s+)/,
  "-\\1",
)

It might not be pretty, but it does work.

Another problem is that pulldown-cmark expects inline math to use single dollar signs (for example, $\sqrt{12}$ becomes 12\sqrt{12}), but kramdown expects double dollar signs instead (e.g. $$\sqrt{12}$$). So, I’m preprocessing that too:

content = content.gsub(
  /(.)\$\$|\$\$(.)/,
  "\\1$\\2",
)

This, too, is not pretty. Ideally, I’d be adjusting the source, i.e. edit my Bear notes,2 but that’s something that will have to wait for later. I’d like to keep the option open to revert to kramdown, in case of emergency.3

Entertainment:

  • Avernum 4: Greed and Glory4 came out just a few days ago, and I bought it instantly. I’ve been a fan of Spiderweb Software’s games since my teens.

  • Portrait of a Lady on Fire5 is a gorgeous period piece. It is refreshing to have a film with so little male energy anywhere near it. I also love the minimal soundtrack — really just one song, La Jeune Fille en Feu. Have a MUBI gift link!

  • I picked up The Haunting of Hill House6 — the book, that is. I started it a few years ago but put it aside, and I regret not continuing with it. It’s a wonderful story, but sure takes a while to get going. It is also queer, remarkably so for its age! Journeys end in lovers meeting.

Toots and skeets:

The year is 50 BC, and all Gaul is using AWS. Only one small village of indomitable Gauls is still selfhosting.

 — @eloy@hsnl.social

Links:

Tech links:

  1. Technically, you can embed Ruby, but it’s a pain and not really intended. There is mruby, too, though I don’t know how compatible most Ruby code is with mruby. In any case, embedding Ruby is not a path I am keen on following. ↩︎

  2. For inline math, Bear expects single dollar signs, just like pulldown-cmark. Updating all my notes to replace the double dollar signs with single ones would be great, because then my formulas would show up nicely in Bear, ever since they introduced math support earlier this year. ↩︎

  3. Making everything (not just code changes, but decisions in general) easy to revert is one of the Software engineering principles that I stand by. I’ll write that up in more detail at some point in the future. ↩︎

  4. Avernum 4: Greed and Glory (Spiderweb Software, 2025), published by Spiderweb Software. ↩︎

  5. Portrait de la jeune fille en feu, directed by Céline Sciamma (Lilies Films, Arte France Cinéma, Hold Up Films, 2020). ↩︎

  6. Shirley Jackson, The Haunting of Hill House (New York, N.Y: Penguin, 1984). ↩︎

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