Michael Kay writes:

> However, some schema processors including XSV
> and Saxon use an algorithm that only requires
> the element declaration to be identified
> uniquely, and therefore let this one through.

Yes, but just to be clear, such processors are in this respect 
non-conforming.  The Schema recommendation is quite clear that your 
example is a UPA violation, and conforming processors MUST report it as 
such.

--------------------------------------
Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142
1-617-693-4036
--------------------------------------








"Michael Kay" <mike@s...>
Sent by: xmlschema-dev-request@w...
02/09/2005 02:40 PM

 
        To:     "'Zafar Abbas'" <zafara@m...>, <xmlschema-dev@w...>
        cc:     (bcc: Noah Mendelsohn/Cambridge/IBM)
        Subject:        RE: Unique Particle Attribution



Yes, the requirement is to identify a particle uniquely, not just an 
element
declaration.

However, some schema processors including XSV and Saxon use an algorithm
that only requires the element declaration to be identified uniquely, and
therefore let this one through.

Michael Kay
http://www.saxonica.com/
 

> -----Original Message-----
> From: xmlschema-dev-request@w... 
> [mailto:xmlschema-dev-request@w...] On Behalf Of Zafar Abbas
> Sent: 09 February 2005 18:49
> To: xmlschema-dev@w...
> Subject: Unique Particle Attribution
> 
> 
> >From my reading of the Unique Particle Attribution constraint in the
> spec, the following schema is a violation:
> 
> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
> 
> <xsd:complexType name="type"> 
> <xsd:sequence>
>                <xsd:element ref="a" minOccurs="0"/>
>                <xsd:element ref="b" minOccurs="0"/>
>                <xsd:element ref="a" maxOccurs="2"/>
> </xsd:sequence>
> </xsd:complexType>
> <xsd:element name="a" />
> <xsd:element name="b" />
> </xsd:schema>
> 
> 
> It can not be known which particle (a) to validate, even through they
> are references to the same element schema component. Is this
> understanding correct?
> 
> Thanks.
> 
> 






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