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Re: life support for DTDs? was RE: misprocessing nam

• To: ricko@a..., xml-dev@l...
• Subject: Re: life support for DTDs? was RE: misprocessing namespaces)
• From: "Wayne Steele" <xmlmaster@h...>
• Date: Fri, 01 Feb 2002 08:29:44 -0800
• Bcc:

Another way to go about it would be to have a special transformation to 
"namespace-normalize" the instance document. This version would be used for 
DTD Validation. The ns-normalized version could then be discarded, and the 
actual instance document presented to the user or application for further 
processing.

Nobody has done this though, because it would require:
1. changes to existing validating parsers
2. consensus on how to write DTDs that would work with this process (compare 
DTDs for XML-Schema and XHTML for two different approaches).

This kind of change would be much easier if XML Processing were a nice  
layered architecture. But it's not.

-Wayne Steele


>From: "Rick Jelliffe" <ricko@a...>
>To: "The Deviants" <xml-dev@l...>
>Subject: Re:  life support for DTDs? was RE:  
>misprocessing namespaces)
>Date: Fri, 1 Feb 2002 21:52:14 +1100
>
>  From: "Alan Kent" <ajk@m...>
>
> > At the risk of looking like a fool (having started reading the thread
> > half way through), I don't quite understand the above. I would have
> > thought you would have done something like (syntax is indicative only)
> >
> > <!XMLNS y "http://foo.bar/baz/">
> > <!XMLNS q "http://rumplestiltskin.com/">
> > <!ELEMENT y:x (y:a, q:a)>
> > <!ELEMENT y:a (#PCDATA)>
> > <!ELEMENT q:a (#PCDATA)>
> > <!ATTLIST q:a age CDATA #IMPLIED
> >               q:type CDATA #FIXED "123">
> >
> > The name spaces would be in scope for the DTD only (not instances).
> > It would allow you to mix different namespaces in one DTD. There would
> > be some scoping ssues to be resolved because you would want to import
> > other DTDs and not accidentally collide on namespace prefixes
> > (eg: DTD namespace declarations are local to the current external entity
> > or something like that).
>
>Oh, the thread was asking "could we extend DTDs to include namespaces?"
>and I was pointing out that we didn't need to change DTDs, just to
>widen their interpretation.  That way we don't have to change any parsers
>or existing DTDs (except to add xmlns declarations for all elements)
>or existing documents, just the validators used. Of course,
>if you write a document that didn't use the literal names given in the DTD,
>that document would not validate if the DTD was used with XML 1.0, but
>that is no different from now.
>
>The approach of revising the DTD syntax for a special kind of schema
>has been tried before, but failed to thrive.
>
>Cheers
>Rick Jelliffe
>
>
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