RE: URI resolver was Re: RDDL and XML Schemas Proposed Recommendation

[Jonathan Borden <jborden@mediaone.net>]

Tim Bray wrote:

>
> At 10:14 AM 25/03/01 -0500, Michael Mealling wrote:
> >Jonathan Borden wrote:
> >> Using RDF you can make statements about URIs that cannot be
> >> disproven by resolving the URI -- indeed there is no guarentee nor even
> >> intention that a URI _can_ be resolved.
> >
> >RDF can do this, sure. But URIs don't know or care about RDF. RDF
> >is simply one of a multitude of applications that use URIs. Each
> >application uses them differently. In RDF's case it uses URIs to make
> >some interesting and complex statements about URIs but that doesn't
> >mean that URIs then inhereit those statements.
>
> I think you guys are straining at gnats.  What RDF does is
> entirely appropriate, and it is a useful thing to make assertions
> using URIs as hooks.  The subtleties about "resolution" are
> lost on most people, which is I think just fine.

I think unfortunately there exists alot of confusion around the whole area
of URIs, what they 'mean', what they do in practice and what they are
intended for. If these discussions help in any small fashion (and at the end
of the day) to cut through this confusion then they are useful. If not, so
be it.

I think the problem is one of language and usage of terms. It is easy to get
into a circuitous discussion if we are using different definitions of words
such as "resolve" and "resource".

Like in many/most endeavors, different people and groups develop different
implementations aimed at solving similar problems. Michael et al. have been
working at one end of the issue, and I've had the opportunity to read
through a few of the _experimental_ RFCs (e.g. 2169,2483) and I see how
Michael and Justin are using the term "URI resolution".

My original question was in reference to issues regarding namespaces: How
can I determine when two namespace URIs can be used interchangably? How can
I determine when one namespace URI is intended to "replace" another? These,
I _think_, are practical questions without definitive answers. Eriv VdV has
been working with the same issues in 'examplotron', has requested and I have
added a new RDDL purpose to assist with this.

http://www.rddl.org/purposes#prior-version

(this purpose indicates that the URI in question is a 'prior version' of the
base URI of the RDDL document)

Now I admit the above referenced exchange did get theoretical and obtuse --
and on rereading I'm not sure that I understand it myself -- however what it
_did_ highlight to me at least, is the fact that different people and
communities use relatively common terms in different ways, and you may think
you both are talking about the same thing when in fact you aren't.

But in the most practical fashion, this is about versioning. Since we are
talking about 'attaching' code to namespaces, these issues become important.
What do you do with a new version of some code 'attached' to a namespace.
What about new versions of libraries referenced by this software. New
namespace? What about the old documents? Solving them isn't always as
straightforward as the simplest solution provides. Anyone who has ever been
in dll hell understands this.

-Jonathan