Re: [RDFa] ISSUE-3 @class and @role for rdf:type

Then one more clarification, if I may ask: what is the potential
conflict with WAI Steven is referring to?

Ivan

Mark Birbeck wrote:
> Hi Ivan,
> 
>> :-)
>>
>> There is a difference, though. @about has been introduced for RDFa.
>> However, (and I may be wrong with that!) @role was introduced with some
>> general, not-necessarily-RDF usage in XHTML2 that RDFa _may_ reuse.
>> And, from the RDFa side, there is no way to predict what the evolution
>> of @role will be in future versions of XHTML2...
> 
> I'm not sure where we're heading with this. :) But perhaps I can just
> clarify a few things about @role, which will show why it was on our
> radar before (but why it probably no longer needs to be).
> 
> First, it's actually a separate module. It was originally distinct
> from XHTML 2, then it was included into XHTML 2, and then it was
> broken back out again. And as Steven said, it's already implemented in
> Firefox. So HTML and XHTML documents will already include @role,
> whether we like it or not, which is the first reason it is legitimate
> to consider it within RDFa.
> 
> Also, @role has a very explicit relationship to RDF...that's the whole
> point of it. @role values are URIs, which give you a 'hook' to go and
> get more information if you want to. Which means that it's also
> legitimate to ask whether the mechanism for establishing that hook is
> via RDFa, or by some other means.
> 
> Finally, the whole rdf:type debate; in the past those using @role did
> define it to be the same as rdf:type, but that was changed. And of
> course, in our own discussions there was a period where @role meant
> rdf:type, but again, that has been changed.
> 
> So...given that no-one is using @role any longer, to represent
> rdf:type, I think it would be quite legitimate to defer what RDFa says
> about @role until the future. We will need to say something about at
> some point though, since it will be increasingly used, but that's no
> more than saying we have to say something about <meta> and <link> in
> HTML now.
> 
> Hopefully you can see that none of the reasons for talking about @role
> are to do with some of us trying to 'sneak' XHTML 2 attributes into
> RDFa by the back door. :) In fact, speaking for myself, I've been
> saying the opposite for a while now--that in the version of RDFa we
> are currently finalising, we should restrict ourselves as much as
> possible to only using HTML 'as we find it', and then have a
> smattering of extra attributes for the more complex constructs.
> 
> Regards,
> 
> Mark
> 

-- 

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