Re: Range extension with redefine

"Hirtle, David" <David.Hirtle@nrc-cnrc.gc.ca> writes:

> A simple question: How does one "extend" a particle's occurrence range with
> <redefine>?  I am familiar with the specification's discussion of valid
> restrictions (http://www.w3.org/TR/xmlschema-1/#cd-model-restriction), but
> there seems to be no way to do the opposite of _extending_ an occurrence
> range.
>
> For example:
>
> one.xsd
> -------
> <xs:group name="some_group">
> 	<xs:sequence>
> 		<xs:element ref="a"/>
> 	</xs:sequence>
> </xs:group>

The following will achieve your goal, but it's clearly limited to
certain restricted cases:

two.xsd
-------
<xs:redefine schemaLocation="one.xsd">
  <xs:group name="some_group">
    <xs:sequence>
      <xs:group ref="some_group"/>
      <xs:element ref="a" minOccurs="0" maxOccurs="unbounded"/>
    </xs:sequence>
  </xs:group>
</xs:redefine>

This points towards a rather extreme design-for-change approach in
which _all_ element references in content models are replaced by
group references to single-element content models, so that you can
change any aspect of the model by a subsequent group redefinition.

ht
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
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Received on Friday, 30 April 2004 05:07:30 UTC