Joachim Schrod writes: > Do you really want to tell us that TEI is not one of the most complex > DTDs that ever got written? no. but its used quite a lot. > Docbook is not an easily understandable one, either. plenty of people seem to manage with it > Could you please bring in other examples? These currently support the > hypothesis that it's "tortuosly difficult". the fact that Docbook and TEI are themselves complex does not demonstrate that the extensibiliy features were/are hard to add. no, i dont have any other convincing examples. but if i asked you to develop a DTD, and said I wanted some extensibility, you would say "sure, no problem, lets see what you need", i bet. sebastian