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Re: Why are relative NS identifiers used?

From: <keshlam@us.ibm.com>
Date: Fri, 19 May 2000 11:45:33 -0400
To: Steve Rowe <sarowe@textwise.com>
cc: xml-uri@w3.org
Message-ID: <852568E4.005691B1.00@D51MTA03.pok.ibm.com>
>> I'm sorry about sounding like a scratched record (now there's a metaphor
>> that's dying out!) ... but please consider my xmlns-binding: proposal.
It
>> is possible to define a way for a namespace to be associated with a true
>> URI without the namespace name having to _be_ that URI.

>Could you post a reference to this proposal, or summarize it, please?


It's pretty darned trivial... Attributes of the form

     xmlns-binding:namespace-prefix="associated-uri-reference"

would be taken as declaring that the associated-uri-reference was associate
with the namespace signified by the previously declared namespace-prefix.
For example:
     <myns:foo
          xmlns:myns="http://my.namespace.name.com"
          xmlns-binding:myns="#"/>

would bind the relative URI reference "#" to the namespace name
"http://my.namespace.name.com".

The interpretation of that binding is not specified at this time (since I'm
just trying to show an alternative to using the namespace name directly,
and the meaning of that is likewise is unspecified). Obviously one could
provide more specific attributes for more specific purposes; the W3C XML
Schemas Working Draft has examples of exactly that approach. Similarly, one
could extend this to allow the binding to associate a list of URIRefs with
the namespace rather than just one, or get into questions of whether or not
it is possible to assert other bindings later in the document.

The point here is that it is trivial to create a syntax that allows us to
avoid placing incompatable demands upon the namespace name itself. Taking
that one step back permits us to say that the namespace name no longer has
to "be" a URI Reference to accomplish any of the goals. It can then revert
to its original intended design -- a string which uses URI Reference syntax
only because (a) we know how to manage that value space to avoid
collisions, (b) it allows us to use syntax-checking code we already have on
hand, and (c) the ability to dereference it may occasionally be useful
(though again, since the question of what it points to was left
unspecified, I think that utility is pretty darned limited.).


This approach seems to meet all the technical requirements voiced so far.

It seems to offend those who believe that everything expressed in URI
Reference syntax must be absolutized.  Personally, I'm afraid that I feel
the objections fall in the category of what Emerson called "a foolish
consistancy".  Every word in this message is syntactically valid as a URI
Reference, but I doubt anyone would want to insist they be absolutized. The
"#" above is a deliberate URI Reference -- but because it's used in an
illustration, you wouldn't want to absolutize it either. Having and using a
consistant syntax does _not_ imply that it must be interpreted the same way
in all contexts.

I think I understand TB-L's vision of a semantic web. But I really do feel
he's trapped himself into looking at only one way of getting there... and
he's chosen a road that involves cutting down the heart of the forest to
permit a better view of the trees.
Received on Friday, 19 May 2000 11:45:59 UTC

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