- From: David Durand <dgd@cs.bu.edu>
- Date: Sun, 4 May 1997 12:26:55 -0500
- To: w3c-sgml-wg@w3.org
At 9:09 AM -0700 5/3/97, Terry Allen wrote: >| I don't think that we can make it easy to combine DTDs without changing >| SGML. But maybe we can figure out a way to declare a namespace for >| elements: to "import" element names in a standard way. You wouldn't be >| able to validate the document but at least it would be clear what the >| elements MEAN. > >A universal typology of human knowledge would do that for you, but >there will never be one. All you can do is refer to well known >external semantics, e.g., via fixed attributes. This is not an >XML issue; the problem is the same in SGML. My proposal, long ago, that we allow "addition" of an element into a content model solves this problem, without a universal taxonomy of knowledge, but simply a more flexible DTD language. The concrete proposal was to allow the extension of content models of the (x | y | z)* form by a declaration that an element "mixes-into" the content of another element. I'm not suggesting that we revisit this -- We decided that we were not going to extend/change the DTD language, for compatibility reasons. This kind of capability is still a great opportunity for a markup-based DTD creation application, but of course we will never have the end-user extensibility that we would get with an extended DTD language. Note that all the facilities one would gain with such a feature can be implemented via parameter entities.... An observation... -- David _________________________________________ David Durand dgd@cs.bu.edu \ david@dynamicDiagrams.com Boston University Computer Science \ Sr. Analyst http://www.cs.bu.edu/students/grads/dgd/ \ Dynamic Diagrams --------------------------------------------\ http://dynamicDiagrams.com/ MAPA: mapping for the WWW \__________________________
Received on Sunday, 4 May 1997 14:04:31 UTC