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   Re: [xml-dev] Finally, what if namespaces == document types ?

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Paul Prescod wrote:

>...Do you agree that it makes more sense to associate
> schemas, stylesheets, etc. with document types than with namespaces?

Actually I think the two are just different. It really depends on the
purpose of the association.

With respect to composing schemas from multiple namespaces, a use case I
considered was when a schema refers to a type e.g.

<xsd:element name="this:foo" type="that:bar"/>

the idea is that the "that:bar" type might be imported from the schema which
_is obtained_ via the namespace URI associated with the "that" prefix.

Without RDDL at the end of the namespace URI, there would be a strong
temptation to place an XML Schema directly there.

There are other examples where it is useful to associate namespace URIs with
resources. This sort of thing appears very clearcut to me.

An entirely different use case might be the association of a document
instance with a set of possible validating schemas i.e. a document type set
> > Perhaps the main issue is that if we are finally jettisoning DTDs, we
> > to have a replacement for the <!DOCTYPE> declaration (modulo the
> > subset - groan).
> A simple PI.

Yes. That's probably the best idea. I don't personally have strong
preference for an attribute at the root element vs. a PI, I suppose there
are tradeoffs to each approach, which is why XML Schema uses an attribute.
But something like:

<?rddl-doctype href="...uri..." ?>

would also do the trick. I am interested to hear people's opinions on the
tradeoffs between the two options

> > This issue is IMHO orthogonal to namespaces.
> That's mostly true. But the thing that has Nicolas and Paul so excited
> is that of the two choices (namespace and doctypes), we've developed an
> infrastructure for associating schemas and stylesheets with the wrong
> thing. The actual file format may be appropriate for doing the other
> task but we just need to declare that best practice is now to associate
> RDDL's with schemas and namespaces to document types, not namespaces.

I don't see how the two use cases are at all mutually exclusive. In terms of
creating a mix of human readable text (XHTML) and a collection of resources
whether they are attached to a namespace URI or a doctype URI, IMHO makes no



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