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Re: XML validity and namespaces

From: Robin Berjon <robin.berjon@expway.fr>
Date: Mon, 04 Apr 2005 01:13:16 +0200
Message-ID: <4250788C.1090109@expway.fr>
To: Elliotte Rusty Harold <elharo@metalab.unc.edu>
Cc: www-tag <www-tag@w3.org>

Elliotte Rusty Harold wrote:
> Rich Salz wrote: 
>> DTD's are ignorant of namespaces.  This means that you cannot write a
>> normative DTD for a namespace
> Actually you can do quite a bit better than that. It's possible to use 
> parameter entity references such that the same DTD can be used for 
> multiple prefixes and the default namespace. The most any instance 
> document needs to do is override two parameter entity declarations.

Yes, it's better than nothing (the SVG 1.1 DTD also does that) but it's 
still not a general (and even less practical) way of validating 
namespaced documents. And Rich's point remains that you cannot write a 
normative DTD for a namespaced language. That's an issue that crops up 
regularly in document-based communities where people have tried to learn 
from HTML's errors and recommend validation against a DTD. 
Unfortunately, since it produces false-negatives, you then end up with 
content producers wondering why their content doesn't validate when 
according to every knowledge of the spec they can muster it is perfectly 

Robin Berjon
   Research Scientist
   Expway, http://expway.com/
Received on Sunday, 3 April 2005 23:13:36 UTC

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