That doesn't appear to be the case to me.
The semantics of tags in XML are entirely controlled by their namespace. XML
Schema provides a formal notation by which the allowable tags in a namspace and
some restrictions on their structural relationships can be written down.
In particular, a schema either does or does not chose to allow, in certain
places, tags from foreign and / or unspecified namespaces to be used (see
xsd:any and xsd:anyAttribute); if no such allowance exists (and if type
inheritance is disabled) then the schema is closed, not allowing for any
extensibility.
XML namespaces are identified by URL; it is assumed that anyone inventing a
schema can by some means invent a unique URL for its namspace.
IANA registration of XML tags is thus totally and completely redundant and
irrelvant.
Deposition of a schema in an IANA repository is perhaps convenient to
programmers as a development aid, but has entirely and exactly zero semantic or
otehr significance to the specification or to the runtime interpretation of
instances of the schema in question.
Bob
(Breaking my promise to be quiet; sorry.)
________________________________
From: Andrew Newton [mailto:andy(_at_)hxr(_dot_)us]
Sent: Mon 5/24/2004 3:58 PM
To: Bob Atkinson
Cc: Douglas Otis; Jim Lyon; MARID
Subject: Re: XML name space (was: suggested new RRtype experiment)
On May 24, 2004, at 6:34 PM, Bob Atkinson wrote:
It MUST be controlled by the standard and not become a prerogative of
every programmer wishing to publish new definitions. Registering the
XML definitions as a token published with IANA controls this name
space.
[...]
This is not how XML works. Really, it just isn't.
I think what Douglas means to say is that there should be a restriction
over and above that which is allowed by XML. Many protocols using XML
do this.
However, an IANA registry will provide an application with no more
knowledge than an HTTP lookup, which is to say almost none. It is
useful only as a place to find the meaning on a token/tag/ns/whatever
and its meta-data (who registered it, where is the spec defining the
semantics, etc...). There is no protocol police to enforce that only
IANA registered tokens appear in the record.
Perhaps we should let Jim get the schema written first and then write
up some examples before we seriously talk about such optimizations.
(And I admit that I'm guilty of doing this too.)
-andy