Proposal for change to CDL Perform (plus TWIST example)

The enclosed example is the full TWIST usecase with the modified  
PERFORM. It will not parse correctly because the schema does not  
support the modified PERFORM. The reference for this is:

http://lists.w3.org/Archives/Public/public-ws-chor-comments/2004Jun/ 
0001.html

My proposal is to remodel the perform such that the tAlias complex  
element is optional (minOccurs) and the alias name is promoted as the  
alias name for the choreography being performed (element name="alias").  
Thus it would be as follows:

<complexType name="tPerform">
     <complexContent>
       <extension base="cdl:tExtensibleElements">
         <sequence>
           <type="cdl:tAlias" minOccurs="0"
                   maxOccurs="unbounded"/>
         </sequence>
         <attribute name="choreographyName" type="QName" element  
name="alias"
                  use="required"/>
       </extension>
     </complexContent>
   </complexType>


As opposed to the current perform which is defined as follows:

<complexType name="tPerform">
     <complexContent>
       <extension base="cdl:tExtensibleElements">
         <sequence>
           <element name="alias" type="cdl:tAlias"
                   maxOccurs="unbounded"/>
         </sequence>
         <attribute name="choreographyName" type="QName"
                  use="required"/>
       </extension>
     </complexContent>
   </complexType>

This would enable my TWIST example to parse correctly.

Thanks to Tony for sorting out some of the parsing issues and apologies 
to Tony for introducing another problem with PERFORM.

Cheers

Steve T