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Re: xmlschema does not support principle of substitutability of subty pe for its supertype

From: Michael Burns <Michael.Burns@sas.com>
Date: Thu, 30 Nov 2000 09:33:20 -0600
Message-Id: <200011301534.KAA13415@tux.w3.org>
Cc: "'xmlschema-dev@w3.org'" <xmlschema-dev@w3.org>
To: ht@cogsci.ed.ac.uk (Henry S. Thompson)
Thanks for the answers.  I will try the substitutionGroup.
Could you be more specific regarding 'various namespace-related problems'?
I admit to not having read all of the specs, and trying to get a schema
working by reading only part of the specs.  So RTFM with some pointers
is an acceptable answer.  :-) 

On Thursday, November 30, 2000, at 06:45 AM, Henry S. Thompson wrote:

> There are various namespace-related problems with your example files 
> as they stand at the moment, but correcting for those, the principle 
> you are addressing is clear and the problem likewise:  type 
> substitutability is not the same as element substitutability. 
> (Element) substitution groups provide the functionality you want. 
> Make all your vertebrates substitutable for Vertebrate (:-) and your 
> problem will be solved: 
> <xsd:element name="Bird" type="BirdType" substitutionGroup="Vertebrate"/> 
> <xsd:element name="BirdOfPrey" type="BirdOfPreyType" substitutionGroup="Bird"/> 
> etc. 
> You'll probably also want to make at least Vertebrate, if not Bird 
> etc. as well, abstract='true'. 
> 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/ 

Michael Burns                        email: Michael.Burns@sas.com
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Received on Thursday, 30 November 2000 10:34:01 UTC

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