Identifying XML Document Types (was XML media types revisited)

John Cowan cowan at
Thu Jan 21 18:59:24 GMT 1999

Paul Prescod wrote:

> If the definition of the namespace (whereever it is) says that the
> namespace's X must contain a Y, then an X *must* contain a Y, just as if
> it were a DOCTYPE declaration. The only difference is that the validation
> is done at some other level, using some other mechanism.

Namespaces needn't have definitions (schemas) in this sense, although
some will.  The model of namespaces as defined by the Recommendation
contains solely names, each tagged as Element, GlobalAttribute, or
ElementType<X>SpecificAttribute, where <X> is a name of type Element.
There is nothing about content models, defaults, or anything else.

> These problems go away if you use the namespace convention in ways that
> are not in contradiction with validation (i.e. #FIXED xmlns: attributes).

Using #FIXED attributes is neither necessary nor sufficient.
What is necessary and sufficient is to alpha-convert all namespace
prefixes so that each namespace has a unique prefix, and to modify the
DTD to use those same prefixes.
John Cowan		cowan at
	You tollerday donsk?  N.  You tolkatiff scowegian?  Nn.
	You spigotty anglease?  Nnn.  You phonio saxo?  Nnnn.
		Clear all so!  'Tis a Jute.... (Finnegans Wake 16.5)

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