[Bug 2554] Should UPA be a model group or particle constraint?

http://www.w3.org/Bugs/Public/show_bug.cgi?id=2554

           Summary: Should UPA be a model group or particle constraint?
           Product: XML Schema
           Version: 1.0/1.1 both
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Structures: XSD Part 1
        AssignedTo: ht@w3.org
        ReportedBy: sandygao@ca.ibm.com
         QAContact: www-xml-schema-comments@w3.org


Currently UPA is in 3.8.6 to constraint model groups. Consider the following:

<complexType>
  <sequence maxOccurs="2">
    <element name="a"/>
    <element name="a" minOccurs="0"/>
  </sequence>
</complexType>

This should be invalid, because for the input <a/><a/>, we don't know which 
element declaration to use for the second <a/>.

The content type of this complex type is a particle, whose term is a model 
gruop (the only model group in the content type). This model group is a 
sequence of 2 element declarations.

It's clear that the sequence model group itself doesn't violate UPA, then how 
do we flag this complex type as invalid? Shouldn't UPA be defined on particles?

Received on Monday, 28 November 2005 02:36:44 UTC