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Re: group-declaration

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 18 Feb 2000 09:09:06 +0000
To: volker.renneberg@acm.org
Cc: www-xml-schema-comments@w3.org
Message-ID: <f5b66vmswr1.fsf@cogsci.ed.ac.uk>
Volker Renneberg <volker.renneberg@acm.org> writes:

> Hi!
> 
> I've a question about the group definition for elements. Let's say I've
> two types A and B and the following group:
> 
> <group order="choice">
>   <element name="c" type="A"/>
>   <element name="c" type="B"/>
> </group>
> 
> In the final XML document, do I have to add the "xsi:type" attribute to
> the "c"-element? Or could I leave them out. Not checking the type of "c"
> results in an ambiguous choice.

That content model is ambiguous, and hence, staying with our SGML and
XML heritage, ruled out.  Ambiguity is defined without reference to
instances or types, purely on the basis of names.

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 Friday, 18 February 2000 04:09:09 GMT

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