Why the LaTeX community should care about SGML
William Hammond · TUGboat · 2020
GELLMU, which stands for "Generalized Extensible L A T E X-Like Markup", is a system for using L A T E X-like markup, though not L A T E X itself, to write consciously for a markup language in the SGML category or in its popular XML subcategory.The basic level of GELLMU offers a way to use L A T E X-Like notation together with a L A T E X-Like newcommand (with arguments) macro facility to write web pages.The advanced level of GELLMU enables one additionally to incorporate certain L A T E X-Like features, such as the use of a blank line for a new paragraph, in writing for an SGML language.The didactic GELLMU production system provides an "article" XML language, with some resemblance to L A T E X itself, that is a rigorous domain for translation to other formats.