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clarification needed wrt group redefinition

From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
Date: 16 Nov 2001 11:39:22 +0000
To: www-xml-schema-comments@w3.org
Message-ID: <f5bu1vvndw5.fsf@cogsci.ed.ac.uk>
A model group definition which contains within it an anonymous complex 
type definition which itself references that very group is allowed, if 
slightly odd:

<xs:group name="list">
 <xs:sequence>
  <xs:element name="item">
   <xs:complexType>
    <xs:sequence>
     <xs:element name="value"/>
     <xs:group ref="list" minOccurs="0"/>
    </xs:sequence>
   </xs:complexType>
  </xs:element>
 </xs:sequence>
</xs:group>

Attempting to redefine such a group by extension is impossible,
because clause 6.1 of Schema Representation Constraint: Redefinition
Constraints and Semantics fires and raises an error.

We need to clarify that the references checked are those within the
content model as such, not within types embedded therein.

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, 16 November 2001 06:38:23 GMT

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