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RE: [XML Schema 1.1] Does mode="none" on a subtype nullify the openness of its parent type?

From: Michael Kay <mike@saxonica.com>
Date: Fri, 5 Jun 2009 18:57:05 +0100
To: "'Costello, Roger L.'" <costello@mitre.org>, <xmlschema-dev@w3.org>
Message-ID: <2CB83CF5DA8B4DE9927A0C4A55601FF3@Sealion>
> > if the base type allows open content, then a type derived 
> from it by 
> > extension must also allow open content.
> Now I'm really confused.
> What value is mode="none"?
> I thought that the point of mode="none" was to enable a 
> subtype to "turn off" the openness of its parent type? If 
> this is not the case, then what value is mode="none"?

You can turn off the open content when deriving by restriction, but not when
deriving by extension.

Makes sense really - restriction can only reduce the permitted content,
extension can only increase it.


Michael Kay
Received on Friday, 5 June 2009 18:02:27 UTC

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