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.