The high-level document formatting system Lout, developed by Jeff Kingston, is essentially an alternative to TeX. While TeX is an extremely good typesetting system, it also is about the worst programming language I have ever seen.
Lout, on the other hand, is based on a clean functional programming language and translates directly into PostScript. One of the essential concepts underlying the document formatting model of Lout is that of galleys; I have undertaken a first attempt to model galleys in a purely functional setting, see here.