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Re: And the DTD says, "I'm NOT dead yet!!"
- From: Norman Walsh <firstname.lastname@example.org>
- To: email@example.com
- Date: Tue, 09 Jan 2001 09:43:15 -0500
/ Bob Kline <firstname.lastname@example.org> was heard to say:
| don't think this is one of them. The most common uses I have seen for
| entities are:
| 1. to create macros for commonly used content-model groups; and
| 2. to create a kludge for working around the lack of support for
| namespaces in DTDs.
| The first is handled fairly well by named groups (<xsd:group name=...)
| and the second problem doesn't exist because XML Schema supports
| namespaces. External entities in DTDs correspond pretty well to the
| <xsd:include ...> element in XML Schema.
The significant feature that seems to be missing, but might be addressed
with <redefine> if it's extended to allow complete redefinition of
model groups and attribute groups (i.e., redefinition without reference
to the original), is the ability to change the groups in derived schemas.
Suppose I have the following PE in my DTD:
<!ENTITY % article.content "para|note|warning">
I can easily construct a derived DTD that does not allow warnings:
<!ENTITY % original.dtd SYSTEM "...">
<!ENTITY % article.content "para|note">
It's not clear that I can do this with XML Schemas, and I do this *a lot*.
Be seeing you,
Norman.Walsh@East.Sun.COM | There has never been a perfect government,
XML Technology Center | because men have passions; and if they did
Sun Microsystems, Inc. | not have passions, there would be no need
| for government.--Voltaire