Re: Extension and all-group

Bob Schloss <rschloss@us.ibm.com> writes:

> IBM XML Schema Quality Checker (available for free download from
> http://www.alphaworks.ibm.com/tech/xmlsqc ) says:
> 
> Effective content model of complexType derivedType includes the <all> as
> part of  an implied sequence with the <all> from that type's ancestor,
> complexType baseType [ located at file:/C:/SQC211/extallgroup.xsd ].  Since
> <all> cannot appear inside sequence, even implied, complexType derivedType
> is invalid.

Very usefully and succinctly put.

>  <all> cannot be used in a complexType which is derived.

Not in general true, unless I've misunderstood -- extension which adds
only attributes, or restriction, are both possible derivations from a
base with <all> which yields <all>, and the restriction case even
includes an <all> in the XML representation of the derived type.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                      Half-time member of W3C Team
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