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RE: multiple types
- From: Gavin Thomas Nicol <firstname.lastname@example.org>
- To: email@example.com
- Date: Mon, 02 Apr 2001 14:52:08 -0400
> > I think people are getting confused between instances and type
> > definitions. In the context of a type definition, it makes great
> > sense to use "is-a" and "has-a" and "extends", etc. This is
> > again, defining the *type*, not an instance.
> Are you saying anything different than there is a difference
> between an XML document and a schema describing the document?
No. Thank's for being succinct :-) The point I was trying to make
it that these are logically orthoganal.
> Examplotron is something that blurs this.
I'm not sure that it does... or if it does, it's because of the
nature of XML type projection. I can say a document A extends
document B if document A has all of the elements and attributes
of document B in the same relative ordering.
In that case, the document sometimes acts as a schema, sometimes
as a document. I think the role distinction is important though
because it allows us to unify type projection no matter what
schema language is used.