Re: GRDDL and OWL/XML

(I am assuming that public-grddl-comments@w3.org is a fine place for 
this discussion, as opposed to public-grddl-wg@w3.org. It would be 
useful to point these comments back to the public-owl list as well - 
Bijan? Is that fine?).

Bijan Parsia wrote:
>
> On May 12, 2008, at 8:55 PM, Dan Connolly wrote:
[snip]
>>> I feel fine in asking a W3C wg to provide a specification *for the
>>> transformation function*, but it should not be the presumption that
>>> saying "Support GRDDL" means providing an implementation.
>>
>> Presumption? It's a straightforward reading of the GRDDL spec, no?
>>
>> "Developers of transformations should make available representations in
>> widely-supported formats. XSLT version 1[XSLT1] is the format most
>> widely supported by GRDDL-aware agents as of this writing ... ."
>> -- http://www.w3.org/TR/grddl/
>
> People are reading the SHOULD as a MUST. That's what I object to. My 
> straightforward reading of the spec is that it is SHOULD. In any case, 
> we supply the transformation in HTML which is way more popular than 
> XSLT :) (albeit, not with GRDDL-aware agents).
Bijan is right here, it is a *should* - the GRDDL specification does not 
specify any programming language in particular, although we *recommend* 
XSLT as it is a widely-supported format and the one that to my knowledge 
all GRDDL transforms use. Now, it would be interesting to see if someone 
wanted to try to current GRDDL implementors (Jena, Redland, etc.) to 
implement ways of running local transforms that aren't XSLT, and I 
highly encourage anyone to look into this, and Jeremy's notes are 
correct. If this was specified as possible in some way, IMHO this would 
help both GRDDL and the Web as a whole.

> (I certainly wouldn't might pointing to a *set* of implementations of 
> our transformation functions, including web services, etc. Then the 
> GRDDL agent could ask the user which to use/install/whatever. As long 
> as the namespace document is actively maintained, that's not so bad, 
> furthermore, it can point to other lists...)

However, at the same point, while it makes perfect sense for the W3C not 
to specify "reference implementations" per se, after all, the reference 
is the specification. However, this does not exclude conformant 
implementations. It does make sense for any specification to have test 
cases and verify that that there are conformant implementations.

I assume OWL2 will (not sure?) have test-cases and conformant 
implementations for its XML->RDF mapping. If one of those conformant 
implementations happened to be implemented in XSLT, I think it would 
make good sense for it to be available as a GRDDL from the namespace doc 
of OWL 2. Has anyone tried this? I would not encourage them, but again, 
would encourage someone to do an OWL2->RDF XSLT and see if it can be 
made conformant.

> Cheers,
> Bijan.
>
P.S.:
Obviously, caching should be done to prevent the issues brought up by 
Henri. The caching issues should not be a reason to not use GRDDL. The 
GRDDL specification does not tell implementers how to cache, but it is 
given as something GRDDL-aware agents should do: "GRDDL-aware agents 
therefore should not retrieve such documents on every reference and 
should retain some cache or local memory of the transformations those 
documents indicate should be applied." [1].

[1] http://www.w3.org/TR/grddl/#ns-bind
>
>

Received on Tuesday, 13 May 2008 00:19:22 UTC