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Re: unresolved MPEG-7 queries/issues

From: Jane Hunter <jane@dstc.edu.au>
Date: Fri, 02 Mar 2001 09:48:21 +1000
Message-Id: <200103012347.f21NllE24200@piglet.dstc.edu.au>
To: ht@cogsci.ed.ac.uk (Henry S. Thompson)
cc: www-xml-schema-comments@w3.org
> Jane Hunter <jane@dstc.edu.au> writes:
> 
> > I'm resending four questions which I sent in an earlier email
> > 
> > (http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001JanMar/
> > 0000.html)
> >  
> > which remain unanswered. I'd appreciate your advice.
> 
> Sorry you haven't gotten official replies, probably my fault.

Not at all - they were sent on Jan 1 amongst 11 questions so to get 7 
answers was appreciated.

To get another 4 positive responses now is great news. 

thanks,

jane

> 
> > -----------------------------
> > 1. Global attributes
> > 
> > When referring to a global attribute whilst declaring a local 
> > attribute,
> > can you modify its "use" attribute value and expect this to overwrite 
> > the
> > original value?
> > 
> > Ex:
> > 
> > <attribute name="myAtt" type="integer"/>
> > 
> > <complexType>
> >    <!-- can we expect the default value, 0, is specified
> >         in the following local attribute? -->
> >     <attribute ref="myAtt" use="default" value="0"/>
> > </complexType>
> 
> Yes, you will be able to do this, we made a change.  There will be a
> small change in the concrete syntax:
> 
>  <attribute name="myAtt" type="integer"/>
>  
>  <complexType>
>     <!-- can we expect the default value, 0, is specified
>          in the following local attribute? -->
>      <attribute ref="myAtt" default="0"/>
>  </complexType>
> 
> > 2. Root Elements
> > 
> > Is there a recommended way to specify a root element amongst global 
> > elements in an instance document ?
> 
> There will be a change to make explicit that this can be a part of
> initial schema assessment invocation.
> 
> > 3. Is it possible to derive an abstract complexType from a non-abstract
> > complexType?
> 
> Yes.  It's slightly odd, but it's allowed.
> 
> > 4. Using derivation by restriction, can we change the content model
> > of a group from choice[0,n] to sequence?
> 
> Yes, see [1], where it says "NOTE: This case allows the "unfolding" of
> iterated disjunctions into sequences. It may be particularly useful
> when the disjunction is an implicit one arising from the use of
> substitution groups."
> 
> ht
> 
> [1] http://www.w3.org/TR/xmlschema-1/#rcase-MapAndSum
> -- 
>   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, 1 March 2001 18:48:39 GMT

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