[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] Re: Derivation by Restriction
> During the writing of some C++ classes for the representation of data > conforming with a particular schema I began to wonder about the > "translation" of an arbitrary schema to domain specific objects > (pretty much in the way exactml or some oracle products do nowadays > with DTDs) and I started to wonder about the implications of > derivation by restriction. > > What I'm looking for is whether the impedance of Der. by Rest. on OO > apps/representations has been considered by anyone before...(not a > basic description of how derivation works,Nikita.But thanks). I think the main point here is that derivation in object orientation means specialization. So if B is a subclass of A, you can replace any occurence of A by B. If you specialize B by restriction, that does not hurt object orientation as long a any instance of B is still a valid instance of A, too. This principle would be violated if you "restrict" B that a subelement required in A is not required in B. In fact, that would not be a specialization or restriction but a generalization. If I read the specs right, you are not allowed to widen the [minOccurs... maxOccurs] interval, so the problem you address seems not exist. Best regards Stefan xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ or CD-ROM/ISBN 981-02-3594-1 Unsubscribe by posting to majordom@i... the message unsubscribe xml-dev (or) unsubscribe xml-dev your-subscribed-email@your-subscribed-address Please note: New list subscriptions now closed in preparation for transfer to OASIS.
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