[fiddlosopher]

For a while I was working on a Haskell-based macro system that compiles TeX-like source to HTML and LaTeX (and whatever else you like) (https://github.com/jgm/HeX). You'd write your macro definitions in a Haskell program, then run this program on the textual source to produce output. What's nice about this is that you can use Haskell's module system to organize your macros, and Haskell's type checker to check for errors. The macros are just Haskell functions, and the types of the functions determine what kinds of arguments are consumed by the macro. I'd like to come back to this some time.