Internal subset equivalent in new schema proposals?

John Cowan cowan at
Mon Nov 30 16:41:45 GMT 1998

Paul Prescod scripsit:

> That's fine, but it isn't clear why XML must be able to support directed
> graphs at its most basic level.

Because all the world isn't a hierarchy, and sometimes the hierarchical
aspect of things is its least important aspect.  Obviously, anything
that is supported in the core could be migrated to an outer layer,
as we are seeing with schema languages.  Indeed in a sense ID/IDREF
support is not in the *core* core, because NVPs don't have to
recognize them.

> We also know that one of the requirements for supporting directed graphs
> *properly* is the ability to do relative addressing (that's why we have
> XPointer).

I don't agree, unless proper support is equated with support that is
robust against change, which is a Good Thing, but not the Only Good
Thing.  Sometimes crude and fast is better than general.

> ID/IDREF also has a very inflexible
> namespace mechanism. Strictly speaking it is "enough" in that every
> element is addressable, but practically speaking it does not allow us to
> express the structure explicitly enough.

IMHO IDs should never carry semantic information: they should always
be arbitrary unique values.

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)

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at
Archived as:
To (un)subscribe, mailto:majordomo at the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo at the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at

More information about the Xml-dev mailing list