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Re: [Fwd: Namespace prefixes for attributes]

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 30 Nov 2000 13:05:31 +0000
To: Philipp Hoschka <ph@w3.org>
Cc: xmlschema-dev@w3.org, aaron.m.cohen@intel.com
Message-ID: <f5bwvdl390k.fsf@cogsci.ed.ac.uk>
Philipp Hoschka <ph@w3.org> writes:

> Is there a way to detect the issue described below as 
> "syntactic atrocity" by writing Schemas in a certain way ? 
> 
> This would mean that the Schema processor can find that an
> attribute qualified with two different namespaces actually
> has the same semantics, and thus shouldn't be used twice
> on an element, i.e. any document that does this is invalid.

[here are the examples from another message]

> AFAIK, this is legal syntax for the SMIL 2.0 language schema:

> <smil xmlns="http://www.w3.org/2000/SMIL20/Language">
> ...
> <smil:video begin="10s" smil20:begin="20s" .../>
> 
> </smil>
> 
> And, BTW, so is this:
>
> <smil xmlns="http://www.w3.org/2000/SMIL20/Language"
> 	xmlns:basic="http://www.w3.org/2000/SMIL20/BasicInlineTiming">
> ...
> <smil:video begin="10s" smil20:begin="20s" basic:begin="30s".../>
> 
> </smil>
> 
> We don't have semantics defined for these syntactic atrocities.

There is no way in XML Schema 1.0 to rule this out -- it's a
particularly poignant example of the need for co-constraints,
timetabled for the next version, not this one.

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 Thursday, 30 November 2000 08:05:41 GMT

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