Re: Unique Particle Attribution constraint and XML schema extensions

• From: Xan Gregg <xan.gregg@jmp.com>
• Date: Fri, 30 Apr 2004 08:35:04 -0400
• To: Tony Opatha <topatha@yahoo.com>
• Cc: xmlschema-dev@w3.org
• Message-Id: <CE4F9D17-9AA2-11D8-812F-000393BB384C@jmp.com>

> Will adding elements right after the:
>
> <xs:any namespace="##other" processContents="lax" minOccurs="0"/>, or
> <xs:any namespace="##any" processContents="lax" minOccurs="0"/>
>
> violate unique particle attribute rule, i.e., we have a case of 
> non-deterministic content model? if they do not violate what is the 
> reason that they don't?

Yes, adding particles with extension will violate the constraint since 
the wildcard is optional, except in the case you mention when you add 
particles in the original target namespace after the ##other wildcard.  
The value of processContents does not affect UPA.  Nor does the value 
of abstract.

One alternative I've seen is to put the wildcard in a wrapper 
extensibility element; I think WSDL uses this technique for 
extensibility.  XML Schema itself uses this technique via the 
xs:appinfo elements.

xan

Received on Friday, 30 April 2004 08:36:26 UTC