There seems to be quite a lot of activity on the “Domain Specific Language” front at the moment. Martin Fowler published “Language Workbenches: The Killer-App for Domain Specific Languages?”, in which he concludes that the common programming pattern of setting up repeating data structures via either very similar lines of code, or an external configuration file, is actually a DSL. He also republished a paper by Dave Thomas entitled “Design to Accomodate Change” on the related topic of table-driven programming.
However, Martin’s essay goes beyond common programming and data techniques to look at the development of specialist tools which he calls “Language Workbenches”. I’m not completely convinced that we need these in the world of XML and XSD. If you have a defined schema for you XML-based DSL (and aren’t all the many *ML langauges just different DLSs?) then any schema-sensitive editor will provide you with good design and editing support. The leading IDEs (e.g. Visual Studio) all have such a tool built into their core capabilities. Surely we now have a sufficiently sophisticated set of XML-based tools and standards that we have an opportunity to exploit synergies rather than re-inventing the wheel?