- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 10 Jul 2000 13:27:57 +0100
- To: "Roger Bishop Jones" <rbjones@rbjones.com>
- Cc: "XML-schema-comments" <www-xml-schema-comments@w3.org>
"Roger Bishop Jones" <rbjones@rbjones.com> writes: > This is a correction to my own recent posting on this topic. > > When I wrote my message I had the wrong end of the stick about what XML 1.0 > says about well-formedness, and this helped me to misread the explanation of > why entity definitions cannot be supported which was quoted by Dan Conolly > in his message. > > Getting this straighter doesn't have much effect on my position, but it > certainly changes the way to describe it, so here's a revised attempt. > > The definitions both of validity and of well-formedness in the XML 1.0 > specification make reference to the DTD, and this presumption that there is > a DTD is a minor issue for the formulation of XML schema. > In relation to validity the approach of XMLschema appears to be to define a > new kind of validity, "schema-validity". > Given that this approach is taken to validity the obvious course in respect > of well-formedness would be to define "schema-well-formedness" giving the > minor adjustments to the notion of well-formedness that are appropriate to > XML documents which use schemas instead of DTDs. With respect, that's not a viable option in my view. At the start of the XML Schema work, we made a fundamental commitment to building on, not replacing, the in-place foundations of XML 1.0, and your proposal would abandon that commitment. > Talking about "schema-well-formedness" may sound odd when the schema is > supposed to define validity rather than well-formedness, but this just > carries forward the historical situation in relation to XML 1.0 that the > content of the internal subset of the DTD, and the existence (or otherwise) > of an external subset (or at least the value of a "standalone" attribute) > plays a role in the definition of well-formedness. This exaggerates the situation considerably. DTDs, if present, may or may not be well-formed, but a conformant processor has _no_ obligation to process an external DTD to determine the well-formedness of an XML document. ht -- Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh W3C Fellow 1999--2001, part-time member of W3C Team 2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk URL: http://www.ltg.ed.ac.uk/~ht/
Received on Monday, 10 July 2000 08:28:01 UTC