Metablogging

In lieu of writing about something useful, I’ll spend some words on this silly blog. I seem to spend more time maintaining it than adding content, so that seems fitting.

Snap version 0.3 was released in December. Unfortunately, I was too busy at the time to update this site to use it. Perhaps that was fortunate, though, since version 0.4 was just released a few days ago. In celebration, I took a little time and updated everything to use 0.4. Version 0.3 introduced the feature that I had really been wanting for a while: a MonadSnap typeclass. Previously, Snap was just its own monad and every request handler had to run in that monad. This was workable, but awkward at times. In particular, it was difficult to build a custom monad up around Snap and use it in a convenient way. This required manual state threading when I wanted to pass information through the system. Now I can easily throw together a custom monad using StateT.

At some point (I believe the 0.4 release), the templating engine that comes with Snap, Heist, switched its backend from hexpat to something custom and more friendly to HTML templates. This let me remove a few ugly hacks from the templates to keep hexpat from collapsing DOM nodes into forms that are not legal HTML. I also do not have to hack in my own doctype declarations anymore, which is a bit of a bonus. The Heist API also became more friendly to blaze-html interoperability. This is much more convenient than manually-constructing XML using hexpat. I do not manually generate much HTML, but there are a few places where it can serve as handy glue between components. A few of my templates ended up breaking in minor ways. Eventually I figured out how to fix them, though, and everything looks as it should now. Heist has actually grown on me quite a bit as a templating system since I first started using it. The bind/apply primitives were not intuitive at first, but once I got the hang of using them, this seems to be the right way to handle templates. I do not think that I have seen another templating system allow for quite as much easy template re-use as this one.

There was also a change from using ByteString everywhere in Snap to using Text in a few places. I like seeing Text used more, and I try to do the same in my own code. Unfortunately, many Snap APIs still use ByteString, so the two mix occasionally. Presumably this is done for speed, but having to convert from one to the other can be a bit of a pain. Maybe this will change one day. I am eagerly waiting for some real Hashable instances for Text, since I feel like mine are hackish. I also feel guilty about orphan instance warnings (but not guilty enough to not throw -fno-warn-orphan-instances at the problem).

Fortunately, the filemanip package was updated to work with mtl-2 just in time. Well, not quite just in time – I had rewritten the parts of the code that relied on it about an hour before the update. I will survive, though. I reverted those changes since I like the filemanip API.

I also finally got around to adding a few of the features that I promised myself that I would add. Maybe these will get me more interested in adding content: