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RE: homework assignment as interpreted by JAR

From: Williams, Stuart (HP Labs, Bristol) <skw@hp.com>
Date: Wed, 16 Apr 2008 16:29:26 +0000
To: Jonathan Rees <jar@creativecommons.org>, "public-awwsw@w3.org" <public-awwsw@w3.org>
Message-ID: <9674EA156DA93A4F855379AABDA4A5C611CE7DD824@G5W0277.americas.hpqcorp.net>

Hello Jonathan,

I think that what the URI dereferences is also the information resource ie. it dereferences what it denotes. Much as in C the dereference on a pointer, eg (*p) can appear either side of an assignment operation. Although GET is often spoken of as 'dereference' I would say that all of GET, PUT, POST, DELETE involve dereference which (though operationalised by the HTTP protocol in the case of HTTP) is conceptually moving to the other end of the pointer (finding the fielding/taylor mapping function that models the resource).

I think that's important because as it's currently drawn, what appears to be dereferenced is one of the representations available at the given instant that the HTTP operation occurs - which leads us back into "the URI identifies" the representation given the confusion around word senses of "identify".

The taylor/fielding value cloud is just a way of modeling an information resource over all time - it's a way of flattening it into an invariant construct (it becomes meaningless to talk about the resource changing over time (though its state may) - if it changes then it is a different resource - because such change would entail a different future or a different past). It is not the intention to say that the information resource is actually organised that way as an implementation - just that it will be in states over time and that those states are projected of a moment as sets of awww:representations, one of which is provided in response to a GET operation using the relevant URI.

Does that make any sense?


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> -----Original Message-----
> From: public-awwsw-request@w3.org
> [mailto:public-awwsw-request@w3.org] On Behalf Of Jonathan Rees
> Sent: 16 April 2008 01:34
> To: public-awwsw@w3.org
> Subject: Re: homework assignment as interpreted by JAR
> Revised diagram based on this morning's meeting is here:
> http://sw.neurocommons.org/2008/inforesource.pdf
> (N.b. that's PDF, not PNG.)
> I've renamed 'abstract document' to 'information resource' since the
> consensus was that they're the same.
> The main reason to include the 'value cloud' in the diagram is to
> help me understand how 'information resource' relates to Fielding's
> formal definition of 'resource'.
> Let me know how you like it.
> Jonathan
> >
> > http://sw.neurocommons.org/2008/inforesource.png
> >
> > which I will not take the time to prettify now (I don't know why
> > the background is gray)
> >
Received on Wednesday, 16 April 2008 16:33:55 UTC

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