RE: RDFa and its relationship to XHTML

Hi Benjamin,

I wrote:
> >Near the bottom of the page you'll see this:
> >
> >  <a
> >   rel="Copyright"
> >   href="/Consortium/Legal/ipr-notice#Copyright"
> >   shape="rect"
> >  >Copyright</a>
> >
> >which is perfectly 'correct' RDFa.

And you replied:

> Unless this was meant as a joke (e.g. "the subset of RDFa 
> that doesn't encode triples")...

No, not a joke! The point is that whether you like RDFa or not, to the 'RDF
mind' HTML 4.01 already "encodes triples", i.e., it already has pretty good
semantics; I find it difficult to interpret the description of the @rel and
@rev attributes in the spec as anything other than that they should provide
a predicate for a triple that has the current document as its subject, and
the value in the @href attribute as the object.

So to answer your question:

> ... what would be the statements an RDFa parser
> should extract from this?

I think it's quite natural to extract:

 <http://www.w3.org/>
  <http://www.w3.org/Copyright>
  <http://www.w3.org/Consortium/Legal/ipr-notice#Copyright>
 .

RDFa then builds on this to say, if we like that 'interpretation' of @rel
and @rev (and it's not very controversial), why not give the 'predicate'
part a bit more power:

  <a
   rel="cc:license"
   href="..."
  >Attribute, sharealike, no-moustaches-drawn-on-faces</a>

And then RDFa chances its arm a little more, and says well if you're happy
with that approach to the predicate, why not allow relationships to be
established between other resources, not just the current document, for
example:

  <img src="photo.jpg" />

  <a
   about="photo.jpg"
   rel="cc:license"
   href="..."
  >Attribute, sharealike, no-moustaches-drawn-on-faces</a>

But whatever you think of the last two 'steps', the first step is pretty
much given by HTML 4.01, and that is why I'm flagging up a problem with the
way that @rel has been used in other embedded formats.

Regards,

Mark


Mark Birbeck
CEO
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Received on Thursday, 8 June 2006 18:08:06 UTC