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RE: UPA violation or not?

From: Michael Kay <mike@saxonica.com>
Date: Thu, 16 Dec 2004 09:34:17 -0000
To: "'Michael Kay'" <mike@saxonica.com>, <xmlschema-dev@w3.org>
Message-Id: <E1Ces1c-0007i7-00@ukmail1.eechost.net>

Responding to my own post, I see that the Thompson & Tobin algorithm
published at

http://www.ltg.ed.ac.uk/~ht/XML_Europe_2003.html

does not report this as a UPA violation, because the edges in the FSA graph
are labelled with element declarations, rather than element particles. The
change in Saxon has arisen because I am implementing the schema data model
(in particular the distinction between element particles and element
declarations) more faithfully.

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

> -----Original Message-----
> From: xmlschema-dev-request@w3.org 
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of Michael Kay
> Sent: 16 December 2004 00:19
> To: xmlschema-dev@w3.org
> Subject: UPA violation or not?
> 
> 
> Xerces reports this schema as a UPA violation, XSV reckons it 
> is OK. Which
> is correct?
> 
> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
> 	<xs:complexType name="bar">
> 		<xs:sequence>
> 		  <xs:element ref="pongo" minOccurs="0" maxOccurs="2"/>
> 		  <xs:element ref="pongo" minOccurs="0" maxOccurs="2"/>
> 		</xs:sequence>
>   	</xs:complexType>
> 	<xs:element name="doc" type="bar"/>
> 	<xs:element name="pongo" type="xs:string"/>
> </xs:schema>
> 
> Saxon 8.1 reports it as ambiguous, my current build of Saxon 
> 8.2 doesn't (an
> unintentional side-effect of an unrelated change). 
> 
> My reading of the spec is that it probably is ambiguous, but 
> that it really
> doesn't need to be.
> 
> Michael Kay
> 
> 
> 
Received on Thursday, 16 December 2004 09:34:22 GMT

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