Hello,
I don't believe that it is a valid schema. My reading of 3.4.2 of the Schema recommendation [1], is that the type rrr is a restriction of the ur-type, and according to "Complex Type Definition with complex content" in the table in 3.4.2, the {content type} of rrr is empty. My understanding is that it was intended that anything that is valid according to a type derived by restriction (sss, in this case) must also be valid according to the base type (rrr); clearly that's not the case for sss here, as it doesn't have empty content.
However, it doesn't appear that any of the cases in the "Schema Component Constraint: Derivation Valid (Restriction, Complex)" [2] prohibits your example. The implementation of the derivation constraints in Xerces-J is extremely faithful to the description in the recommendation, and so the internal error you saw results.
I'll send a request to the Schema Working Group to look at this apparent hole in the recommendation. In the meanwhile, Lisa Martin said she will look into fixing the problem in Xerces-J.
Thanks,
Henry
[1] http://www.w3.org/TR/xmlschema-1/#declare-type
[2] http://www.w3.org/TR/xmlschema-1/#derivation-ok-restriction
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Henry Zongaro XML Parsers development
IBM SWS Toronto Lab Tie Line 778-6044; Phone (416) 448-6044
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Subject: Schema bug?
The following schema causes "internal Xerces error".
---------------------------------------------
<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'>
<xs:element name="dummy"/>
<xs:complexType name="rrr" />
<xs:complexType name="sss">
<xs:complexContent>
<xs:restriction base="rrr">
<xs:sequence>
<xs:element name="dummy"/>
</xs:sequence>
</xs:restriction>
</xs:complexContent>
</xs:complexType>
</xs:schema>
---------------------------------------------
Here is the error message:
[Error] subst2.xml:3:67: Schema error: ComplexType ',sss': internal
Xerces error.
If my understanding is correct, the above schema should be a valid
schema. ... Or it isn't?
regards,
--
Kohsuke KAWAGUCHI +1 650 786 0721
Sun Microsystems [EMAIL PROTECTED]
