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RE: [XML Schema 1.1] I respectfully recommend these changes to <assert> and <alternative>

From: Michael Kay <mike@saxonica.com>
Date: Tue, 12 May 2009 15:08:29 +0100
To: "'Costello, Roger L.'" <costello@mitre.org>, <xmlschema-dev@w3.org>
Message-ID: <FED59BB6213B4956B97E5793DD3F5AFD@Sealion>
> 
> Wouldn't it be easier and better if the XPath was not 
> restricted and allowed us to factor in information, 
> regardless of where it is located in the tree?
> 

It's a conscious design decision that when you define what constitutes a
valid book, the definition should be context-independent: if it's a valid
book in one situation, then it remains valid in any other situation.

XSLT and XQuery rely on this context-independence - if a function returns a
valid book, or if you select a valid book by XPath navigation, then the
element can be used in any context that expects a valid book, without having
to be revalidated to ensure it's still valid in the new context.

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay 
Received on Tuesday, 12 May 2009 14:09:11 GMT

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