This blog is built on hakyll, a static site generator written in Haskell. I have been running on Hakyll 3.x for quite some time now, but Hakyll 4 was released in January. I kept telling myself that I would update - I even had the port mostly working a few months ago. I never got around to finishing it, though. Until today, that is. There should be no visible changes if I did everything right, but the code is much cleaner. It was essentially a rewrite, so it was a good opportunity to make some style fixes. I had to cheat and work off of another example of Hakyll usage, but it all worked out in the end.
The biggest change from Hakyll 3 to Hakyll 4 was a transition from an arrow-based API to a monadic API. Hakyll was my first exposure to arrows, and I use some small parts of the arrow API in my own code. I think the monadic API is a bit simpler, but have no strong opinions. It does require fewer odd combinators in day-to-day use. I like the concept of arrows just fine, but I haven't used them enough to always remember what each combinator does off-hand. I think the biggest change that affected me is that Hakyll 4.1 uses pandoc 1.10, which just makes package maintenance easier (most other things are updating to the newer pandoc, too). There also seem to be some fancy new features in the template system in Hakyll 4.3 that I am not yet using. I might try out the new pagination and teaser functionality.