Re: Identification of RDFa content

Hm. If we want a quick usage and spread of RDFa, then this may not be
fully satisfactory at least in my view. Nobody knows when XHTML 1.2 will
be published as a Rec, let alone XHTML 2.0 (the group's charter has just
been sent to the AC, ie, there is not group yet!). What happens in the
meantime?

My hope is that the XHTML1.x RDFa module, as well as the final technical
spec, will be published way before the full XHTML1.2, and that we can
start using RDFa big time and quickly. Using a (possibly optional)
profile tag might help that.

Of course, we could rely on GRDDL and, say, Fabien's XSLT script [as an
aside: we should have a clear test set; Fabien's script, for example,
does not produce the same result as Elias' one, I think there are
missing features...]. However, if I take an environment like Redland,
that means that it would have to go and execute an 'outsider' script
every time it wants to retrieve RDFa content (which also means that it
would not work off-line) whereas if it knew via a profile that this is
RDFa, it could parse the file right away and locally.

Bottomline: I am still not convinced:-(; and I do not see harm in
declaring a separate profile...

Ivan

Ben Adida wrote:
> Ivan,
> 
> Sorry for the delayed response here.
> 
> RDFa is meant to be a natural part of XHTML. In other words, declaring a
> document to be XHTML 1.2 or 2.0 is enough to make a parser look for
> RDFa. This may be done by specifying a GRDDL profile in the XHTML 1.2
> and 2.0 namespace documents.
> 
> Of course, parsers may choose to be more promiscuous than that and look
> inside XHTML 1.1 and 1.0 if they so choose...
> 
> -Ben
> 
> Ivan Herman wrote:
> 
>>This may have been discussed before, in which case apologies. I have not
>>seen a reference to it in the latest draft.
>>
>>The question: how does one discover that an XHTML file is 'RDFa-d'? The
>>issue stroke me as a result of some discussions lately around the
>>Tabulator[1] and Chris Bizer's announcement[2]. In both cases one can
>>see engines that are able to make an indirect step, so to say; ie, they
>>get a URI to a traditional site, but they can deduce the presence of a
>>corresponding RDF data which they can add to their graph they build and
>>explore. Examples are the <link references to RDF data, or the GRDDL
>>profile.
>>
>>Hence the question again: how does an automatic procedure 'know' that an
>>XHTML file contains RDFa encoded extra RDF data? Of course, a processor
>>could RDFa process *all* XHTML file it gets hold of, but it may be worth
>>adding some standard notification. Also, if such identification was
>>around, the same URI could be used both for human consumption and for an
>>RDFa-aware RDF environment.
>>
>>One would think of a profile attribute or is some sort of a special and
>>predefined <link>... whichever. Something would be good.
>>
>>Any thoughts?
>>
>>Ivan
>>
>>
>>[1] http://dig.csail.mit.edu/breadcrumbs/node/165
>>[2] http://lists.w3.org/Archives/Public/semantic-web/2006Oct/0065.html
>>
> 
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
URL: http://www.w3.org/People/Ivan/
PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf