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Re: HTML WG last call remark (no way to declare entities?)

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>
Message-ID: <f5baefqxj8y.fsf@cogsci.ed.ac.uk>
"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

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