[Bug 5293] Subsumption

http://www.w3.org/Bugs/Public/show_bug.cgi?id=5293





------- Comment #5 from mike@saxonica.com  2007-11-29 10:28 -------
>I suppose it is too late to insist that the structure of the derived type should mirror the structure of the base type. 

That gets back to the 1.0 approach which disallows many perfectly reasonable
restrictions.

In many ways, starting from scratch, I would prefer a syntax for restriction
where you define the differences rather than defining the new type and
requiring the system to check consistency. That would be far easier from a
maintenance viewpoint, because a change to the base type would then be
automatically inherited by its subtypes. We do this for attributes
(use="prohibited"), we do it for facet-based restriction, we do it for
assertions; it's a shame we can't do it with content models. But that's opening
up the discussion too far for comfort.

Received on Thursday, 29 November 2007 10:28:28 UTC