Your Own Document Language (Yodl) is a pre-document language

 Yodl is a package that implements a pre-document language and tools to
 process it. The idea of Yodl is that you write up a document in a
 pre-language, then use the tools (e.g. yodl2html) to convert it to some
 final document language. Current converters are for HTML, man, LaTeX
 SGML and texinfo, a poor-man's text converter and an experimental xml
 converter. Main document types are
 "article", "report", "book", "manpage" and "letter".
 The Yodl document language was designed to be easy to use and extensible.