SiSU written in Ruby can output Documents in PDF PS LaTeX HTML etc

I found this meta-markup language which outputs to a variety of formats, including pdf, ps, LaTex, HTML etc etc. Very interesting idea and includes a whole other level of complexity with database output support! If you're familiar with LaTeX you know that it is very flexible and very powerful but occasionally can be a little obtuse. I found the best introduction is The Not So Short Introduction to L ATEX2ε

Using markup applied to a document, SiSU can produce plain text, HTML, XHTML, XML, OpenDocument, LaTeX or PDF files, and populate an SQL database with objects 3 (equating generally to paragraph-sized chunks) so searches may be performed and matches returned with that degree of granularity (e.g. your search criteria is met by these documents and at these locations within each document). Document output formats share a common object numbering system for locating content. This is particularly suitable for "published" works (finalized texts as opposed to works that are frequently changed or updated) for which it provides a fixed means of reference of content.