W3C home > Mailing lists > Public > xmlschema-dev@w3.org > April 2007

RE: Permit (greedy) conflicting wildcards

From: Michael Kay <mike@saxonica.com>
Date: Tue, 10 Apr 2007 10:27:02 +0100
To: <noah_mendelsohn@us.ibm.com>
Cc: "'Pete Cordell'" <petexmldev@tech-know-ware.com>, <xmlschema-dev@w3.org>
Message-ID: <00ec01c77b52$65c6a380$6401a8c0@turtle>

> I think 
> you're looking for something more, which is for the component 
> such as a complexType resulting from a given source level 
> declaration in a schema document to have the same validation 
> semantics regardless of the larger schema in which it's employed.

Well, the main thing I'm looking for is conformance with the rule in
XSLT/XQuery which says that a schema component used at query/stylesheet
compilation time must have the same semantics as the same component when
used at run-time. And yes, I'm trying to do this without "freezing" the
whole schema, because XSLT/XQuery also allow new components to appear at
run-time (for example, from xsi:schemaLocation in an instance document
supplied as input to the transformation) that were not known at compile
time. So in this sense you're right: I'm trying to find rules that allow the
schema as a whole to be extended while retaining confidence that the
assumptions I made at query compile time relating to type-safety are still
true when the query is executed. I'm trying to do this by freezing the parts
of the schema on which compiled queries depend.

If one took the "late binding" principle to extremes, then it would be
impossible to do anything useful at query compilation time, which would
obviously be unacceptable. So it's a question of finding the right level of
late binding.

Michael Kay
Received on Tuesday, 10 April 2007 09:27:08 UTC

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