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RE: Substitution Groups in Local Elements?

From: <Simon.Cox@csiro.au>
Date: Tue, 23 Apr 2002 13:38:08 +0800
Message-ID: <116D27C8E12BD411B3AB00B0D022B0B8010E55D8@yate.wa.csiro.au>
To: ht@cogsci.ed.ac.uk, simeon@simeon-ltmh.research.bell-labs.com
Cc: w3c-xml-schema-ig@w3.org, simeon@research.bell-labs.com, wadler@research.avayalabs.com, www-xml-schema-comments@w3.org
I was aware of this constraint.  
But I never understood the reason for it.  
I have no problem with a substitution group head needing to be global.  
But why should members also be global?  

_____
[This mail represents part of a discussion of work in progress 
and should not be used for any purpose without my permission.] 
_____
Simon.Cox@csiro.au  CSIRO Exploration & Mining
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http://www.csiro.au/page.asp?type=resume&id=CoxSimon

> -----Original Message-----
> From: ht@cogsci.ed.ac.uk [mailto:ht@cogsci.ed.ac.uk]
> Sent: Tuesday, 23 April 2002 2:11 AM
> To: Jerome Simeon
> Cc: W3C XML Schema IG; Jerome Simeon; Philip Wadler;
> www-xml-schema-comments@w3.org
> Subject: Re: Substitution Groups in Local Elements?
> 
> 
> [technical discussion on the IG, please]
> 
> Jerome Simeon <simeon@simeon-ltmh.research.bell-labs.com> writes:
> 
> > Can a local element belong to a substitution group?
> > 
> > We can find nothing in Schema Part I that prohibits this, 
> but if it is
> > permitted, it is not clear what it would mean.
> 
> The Schema for Schemas rules this out:
> 
>  <xs:complexType name="localElement">
>   <xs:complexContent>
>    <xs:restriction base="xs:element">
>     . . .
>     <xs:attribute name="substitutionGroup" use="prohibited"/>
>                                            ^^^^^^^^^^^^^^^^
>    </xs:restriction>
>   </xs:complexContent>
>  </xs:complexType>
> 
> This only applies to the XML representation layer, of course.
> 
> It's a bug that there's no clause in "Schema Component Constraint:
> Element Declaration Properties Correct" ruling this out for 
> components 
> as well.
> 
> ht
> -- 
>   Henry S. Thompson, HCRC Language Technology Group, 
> University of Edinburgh
>           W3C Fellow 1999--2002, 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/
>  [mail really from me _always_ has this .sig -- mail without 
> it is forged spam]
> 
Received on Tuesday, 23 April 2002 01:48:38 GMT

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