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Re: WebArch Ambiguity about Objects, PLUS Suggested Major Replacement

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 30 Dec 2002 14:49:30 -0500
Message-Id: <200212301949.gBUJnUs13563@wadimousa.hawke.org>
To: Mark Baker <distobj@acm.org>
cc: www-tag@w3.org


> You realize that this is httpRange-14, right? 8-)

It's certainly related, but this issue goes a little deeper than 14.

> On Mon, Dec 30, 2002 at 12:32:02PM -0500, Sandro Hawke wrote:
> > > Agents identify objects in the system (called "resources") with
> > > Uniform Resource Identifiers (URIs), defined in [RFC2396].
> > 
> > Sounds like data-structure objects, since they are "in the system".
> 
> That's the "http URIs identify the data/document" view.  My view is
> that http URIs can identify anything, and therefore *I* am on/in/part-of
> the Web because I claim that "http://www.markbaker.ca" identifies me.

I'm afraid you're too used to object-oriented design to notice the
distinction we need to make here.  (Sorry if that sounds ad hominem; I
mean no disrespect, I'm just trying to be direct about sorting this
out.) 

In python, is an instance of xml.dom.Document an XML document?

Of course it is not.  It's a python data structure which stores
information about an XML document.   Right?   But when you're
programming, you try not to make that distinction!

Here, let me try plugging in you, as a Resource, into some of the
examples I flagged of "resource" being using in the data-structure
sense.   I can't say these with a straight face.  Can you?

> Owners of important resources SHOULD make available representations
> that describe the nature and purpose of those resources.

Since Mark Baker does seem to be an important resource,

  The owners of Mark Baker SHOULD make available representations
  that describe his nature and purpose.

Obviously, Mark Baker doesn't have an owner, so this is nonsense.
It's the owner of the identifier "http://www.markbaker.ca" who is
supposed to do something here.

> The Web is a universe of resources. 

  The Web is a universe of things like Mark Baker, his house, and
  his coffee pot.    

Somehow this is different from the real universe?   Saying the web is
the universe is nonsense.

> One can append a fragment identifier to a URI to yield an identifier
> for part of, or a view of, a resource

  One can append a fragment identifier to "http://www.markbaker.ca" to
  yield an identifier for part of, or a view of, Mark Baker.  For
  example "http://www.markbaker.ca#workTel" might identify the part
  of Mark Baker, just past his left elbow, which is his work telephone
  number.  Similarly, "http://www.markbaker.ca#publications" is another
  fragment of Mark, just below his sense of humor and to the left of
  his sense of justice, very near his experience of getting up this
  morning, which is the list of his published works. 

Don't get me wrong.  You can certainly use "http://www.markbaker.ca"
to identify yourself, but only indirectly: Mark Baker is the primary
subject of some information available on the web at
"http://www.markbaker.ca".  Humans may not even notice the difference,
but RDF does.

I should add that I'm generally a fan of REST and what I'm saying her
in no way conflicts with it.  REST says: let's have the protocol in
our distributed object system be BELOW the procedural interface --
we'll let people access the data (the object state) directly and they
can example/manipulate it on the client; object encapsulation will be
only advisory at the web-data layer.  This is a great approach, as you
obviously know.    

The distinction I'm trying to make only matters when information
systems collide.  For example:

Within a particular application, perhaps a school's class-registration
database, students can use their home page URLs to identify
themselves.  That works fine until that data gets merged on the
Semantic Web with data about, oh, student's home pages.  Now we're
saying things like "there is a thing enrolled in CompSci 101 which has
a last-modify date of 15 minutes ago."  This is really not a very good
information system design!  On the other hand, it's just fine (and
really not much more work) to say "there is a thing enrolled in
CompSci 101 which has a home page which has a last-modify date of 15
minutes ago."  Wouldn't you prefer we keep these things straight?

     -- sandro
Received on Monday, 30 December 2002 14:53:17 GMT

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