W3C home > Mailing lists > Public > public-swd-wg@w3.org > June 2007

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

From: Ivan Herman <ivan@w3.org>
Date: Thu, 28 Jun 2007 12:06:10 +0200
Message-ID: <46838812.6060304@w3.org>
To: mark.birbeck@x-port.net
CC: Ben Adida <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>, SWD WG <public-swd-wg@w3.org>

as I said: I am not sure about the usage of @role, I did not follow the
details of that. I am happy to disregard @role for now.

I also agree that rdf:type is important, so it is probably a good idea
to give a shorthand (just like Turtle does). @isA sounds perfectly fine
to me...


Mark Birbeck wrote:
> Hi Ivan,
> I also prefer a new attribute.
> The only thing I feel really strongly about is that we don't use @role
> for rdf:type, since I think that will come back to bite us in the
> future. So for me, that leaves two choices, use @class or use a new
> attribute.
> I can live with using @class, but I do agree that it comes with some
> baggage. I don't mean that from the point of view of some kind of
> 'backlash', since I think people are using @class semantically already
> (even without using microformats). What I mean is that I can easily
> imagine people forgetting to put foaf:Person (for example) in the
> class attribute on the containing element, since novice authors would
> probably see it as 'I must set the CSS class to foaf:Person for this
> to work'.
> I also believe that rdf:type is so important that it should be part of
> the core RDFa attributes, that are independent of any host language. A
> host language may have an additional way of doing this, and we might
> even decide in the future to use @class in HTML after all. But by
> having our own attribute, it means that there is a core way of marking
> up rdf:type that is always there, no matter what language is the host.
> So to summarise; my preferred approach would be to leave @class
> undefined for now--we can always come back to this in a future
> version--and use @isA or something like that, to indicate the rdf:type
> of something.
> Regards,
> Mark
> On 28/06/07, Ivan Herman <ivan@w3.org> wrote:
>> I am a bit uneasy with the usage of @class. _I know_ that the formal
>> semantics of @class allows this type of usage, and I also know that the
>> microformat community uses that trick, I still feel that usage @class is
>> putting a semantics into the attribute that a lambda user would not
>> expect. (And yes, I am also uneasy with the way the microformats reuse
>> attributes like title, class, or abbr...).
>> I would prefer to use a dedicated attribute if we need it (or simply
>> stick to the rel="rdf:type", which is at disposal anyway).
>> I must admit I am not fully familiar with the discussion behind @role to
>> decide whether @role should be introduced in RDFa for XTHML1, too, to
>> cover this usage, or whether a different @type or similar should be
>> introduced. I guess this discussion should start _if_ ISSUE-3 is not
>> resolved for @class
>> Ivan
>> P.S. Having said all that: I do not consider this issue as life
>> threatening:-) Ie, resolving it quickly is probably more important than
>> spending lots of time finding the best solution.
>> Ben Adida wrote:
>> >
>> > Another issue up for discussion.
>> >
>> > ISSUE-3
>> > http://www.w3.org/2006/07/SWD/track/issues/3
>> >
>> > The question is what @class and @role should yield in XHTML1.1+RDFa. We
>> > don't have complete consensus on this (we specifically note Steven
>> > Pemberton's worries about the reuse of the @class attribute), but the
>> > current solution, as accepted in the Primer and in many use cases,
>> is as
>> > follows:
>> >
>> > @class yields rdf:type only if the value is namespace-qualified. @class
>> > contains a space-separated list of values. Only those values which are
>> > namespace-qualified yield rdf:type triples.
>> >
>> > @role does not exist in XHTML1.1, so it is not used here. In XHTML2, it
>> > is expected to yield a triple with predicate xhtml2:role.
>> >
>> > +1 if you agree, otherwise email your disagreements and explanation.
>> >
>> > -Ben
>> >
>> -- 
>> 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


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

Received on Thursday, 28 June 2007 10:06:08 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 17:31:43 UTC