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From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Fri, 16 May 2008 17:41:56 +0100
Message-ID: <482DB954.6080509@hpl.hp.com>
To: Harry Halpin <hhalpin@ibiblio.org>
CC: Bijan Parsia <bparsia@cs.man.ac.uk>, public-grddl-comments@w3.org, public-grddl-wg@w3.org, alanruttenberg@gmail.com

To record my opinion on these points, which you agreed differed ...

>    In effect, while it appears active GRDDL WG members on the list  
> recognize the dangers posed by someone thinking an conformant GRDDL 
> transformation in XSLT for OWL2/XML to RDF is more "normative" than some 
> other transformation, it appears to be the feeling of the majority of 
> the people from the GRDDL Working Group that the benefits of having such 
> a GRDDL transformation accessible from the namespace document of OWL2's 
> XML syntax outweigh the costs.


> This is in particular  *if* the OWL2 Working Group believes that 
> RDF-aware agents may want to access information in OWL2 in RDF and may 
> not have their own locally installed OWL2 XML to RDF transformer.


> So:
>    1) It seems general opinion in the GRDDL WG that having a GRDDL 
> Transformation Property point to a non-executable list of 
> implementations is not a useful use of GRDDL, and the GRDDL WG did not 
> explicitly discuss this possibility when creating the GRDDL 
> Specification or test-cases. A GRDDL transformation, while not 
> necessarily XSLT, is usually executable, and currently all examples are 
> in XSLT.

-1 I liked Bijan's plug-in architecture immensely.

>    2) However, while the "cost" of alienating developers of other 
> non-GRDDL transformations may exist, this is a misunderstanding about 
> the "normative" nature of GRDDL transformations. In particular, a list 
> of other conformant implementations could be accessible at the namespace 
> document. Also, a few sentences explaining GRDDL and the fact that it is 
> no more "normative" than other implementations could be included in the 
> namespace document. If this does actually cause problems, these problems 
> could be dealt with re the usual feedback channels of the W3C. The 
> advantage of having a GRDDL from OWL 2 to RDF is that it is to a larger 
> audience (RDF users without an explicit OWL 2 to RDF transform), who 
> might otherwise be unable to have what benefits OWL 2. in RDF, can have 
> these benefits with a minimal of work.


>    3) Re the possibility of the OWL namespace document being overloaded 
> by requests for the transform, we do in the specification encourage 
> caching of GRDDL transformations. Regards the possibility of GRDDL 
> transformations being "automatically" run, this is a matter of local 
> policy. Current libraries such as Redland and Jena do allow GRDDL to be 
> turned on explicitly by the local client.


>    Although this is not the solution that Bijan wants per se, think this 
> is the general opinion of the GRDDL WG members who have responded so far 
> on this list, except for possibly Jeremy Carroll. 

I only disagree on that point. I would be quite happy with a grddl 
transform specified in prose, in addition to one in XSLT.

I hope (but don't know) that the Jena implementation would quietly 
ignore it. If it didn't that would be a bug. (Although I am not sure 
what the support status of that component of Jena will be in the future).

> Thanks for the 
> provocative and intelligent critiques and comments re GRDDL and OWL 2.
>    The choice of whether or not to include a GRDDL transformation that 
> is an XSLT from OWL2 XML to RDF is, of course, in the competent hands of 
> the OWL 2 WG. However, I do hope this feedback helps clarify things.


If there is any other WG member who supports my -1 I would suggest that 
that part of the message be struck before sending to the OWL WG
(OTOH David might strongly disagree with me, and HP would abstain, at 
least for another two weeks :) )

Received on Friday, 16 May 2008 16:42:52 UTC

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