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General entities should be eliminated

From: James Clark <jjc@jclark.com>
Date: Thu, 08 Jul 1999 17:48:42 +0700
Message-ID: <3784820A.98CA573F@jclark.com>
To: www-xml-schema-comments@w3.org
I would like to add my voice to those urgin the elimination of general
entities, for the following reasons:

1.  No amount of weasel wording in the spec can disguise the fact that
this is in violent conflict with the XML 1.0 Recommendation.  The Schema
WD is operating on XML documents that the XML 1.0 Recommendation
requires conformant processors to reject.

2. It is also not conformant with the XML Namespaces Rec.  The XML
Namespaces Rec does not allow entity names to be qualified, in
particular an entity reference has to be an NCName.  Since the Schemas
WD uses namespaces to identify the schemas, I am at a loss to see how
the schema in which an entity is defined could be determined in a manner
that is conformant with the XML Namespaces Rec.

3. It prevents a clean layering of XML Schemas on top of XML 1.0.  For
example, it makes it impossible to implement XML Schemas on top of a
standard API like SAX.

4. It is conceptually broken. Entity declarations do not belong in
schemas; the information they provide is of a completely different kind
to the other kinds of information.  This mistake of SGML was repeated in
XML 1.0. I would be sad to see it repeated again.

5. The functionality it provides duplicates that provided by another WG,
namely the XML Linking WG. The right way to do what entities do is with
links.  XML Schemas and XLink should coordinate so that it is possible
to have a kind of link that is validated with respect to the target of
the link.

James
Received on Thursday, 8 July 1999 06:49:35 GMT

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