In short, you really don't want to get into this unless you enjoy suffering. Even programmers are reticent to deal with it. DSL's are determined by ISO/IEC 10179:1996 DSSSL (Document Style Semantics and Specification Language)

To determine how a document made according to a DTD looks, I have to write a DSL. (Document Style Language) file, which says--in effect--any time I start a new chapter (with a DTD command of '<chapter>Chapter One: My Tome</chapter>, center it, put it in bold, and font size such and such. It also says "everytime I use the paragraph

marker, then make a 1.5" left margin, double space, etc." DSL's are not easy to write, and are equivalent in tedium to any detailed programming language. XML solves this somewhat.

A DSL is read by a special program--free download--called Jade, written by visionary Jim Clark (who also spearheaded DSSSL standards) in order to create a printable copy, like PDF. But, again, DSL's are hard to write. There is an automated menu-driven gizmo for writing XML style sheets--XSL's--which makes XML preferable to SGML.