- From: Michael Kay <mike@saxonica.com>
- Date: Tue, 26 Jun 2007 13:16:02 +0100
- To: "'Henry S. Thompson'" <ht@inf.ed.ac.uk>, "'Eliot Kimber'" <ekimber@innodata-isogen.com>
- Cc: <xmlschema-dev@w3.org>
> The motivation is to provide an invariant rather like that of > object-oriented programming languages: any valid member of a > type defined by restriction is also a valid member of the > type defined by its base. I think that what this demonstrates is that's there's a set of use cases where what people want is "a schema that's the same as X except for difference D", with no constraints on the nature of the difference D - it might be making a mandatory element optional, or adding values to an enumeration, or changing something from float to double. People imagine that's what xs:redefine was designed for, and perhaps it should have been. Rather like overriding in XSLT, come to think of it - no constraints requiring compatibility with whatever it is you are overriding. Michael Kay http://www.saxonica.com/
Received on Tuesday, 26 June 2007 12:16:33 UTC