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[Bug 2112] R-123: A question about redefining redefines

From: <bugzilla@wiggum.w3.org>
Date: Fri, 09 Sep 2005 15:13:35 +0000
To: www-xml-schema-comments@w3.org
Message-Id: <E1EDkZL-00070e-5s@wiggum.w3.org>


           Summary: R-123: A question about redefining redefines
           Product: XML Schema
           Version: 1.0
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: XSD Part 1: Structures
        AssignedTo: ht@w3.org
        ReportedBy: sandygao@ca.ibm.com
         QAContact: www-xml-schema-comments@w3.org

There are situations in which the redefinition of a type, and the subsequent 
redefinition of the redefined type, are desirable. One such case is where a 
schema user would like to extend a type, not just from the original source but 
based on the extension of another schema user's extension (Company C extends 
type T from Company B, who picked it up from Company A and redefined it).

It appears that this is discouraged in the Rec. From 4.2.2:

"In all cases there must be a top-level definition item of the appropriate name 
and kind in the redefined schema document. 

NOTE: The above is carefully worded so that multiple equivalent redefining of 
the same schema document will not constitute a violation of clause 2 of Schema 
Properties Correct (3.15.6) , but applications are allowed, indeed encouraged, 
to avoid redefining the same schema document in the same way more than once to 
forestall the necessity of establishing identity component by component 
(although this will have to be done for the individual redefinitions 

Some validators require that the redefined schema contain a type definition for 
a type that is to be redefined - that a redefinition is not sufficient. So it 
is not possible to redefine a redefined type. So the question is, is this 
something that is likely to change, or will validators vary on whether or not 
they support cascading redefines?
Received on Friday, 9 September 2005 15:13:37 UTC

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