- From: Shane McCarron <shane@aptest.com>
- Date: Thu, 24 May 2007 10:39:15 -0500
- To: José Manuel Cantera Fonseca <jmcf@tid.es>
- CC: mark.birbeck@x-port.net, RDFa <public-rdf-in-xhtml-tf@w3.org>
Just to be clear, are you suggesting that @content now be a URI type instead of a CDATA type? To date content has been a way of specifying content for a property when you do not want to use the actual content of the element in question. I think, anyway. José Manuel Cantera Fonseca wrote: > > Hello, > > I'm suggesting the following counterproposal which sounds more > orthogonal to me and avoids introducing a new attribute: > > <div about="http://joost.com/some-film"> > <div property="dc:title">A film</div> > <div property="dc:description"> > Some notes on the film > </div> > <span property="dc:subject" content="http://film-vocab/horror" > datatype="rdf:resource">Category: > Horror</span> > </div> > > Best wishes > > Mark Birbeck escribió: >> >> This is a proposal for the requirement at: >> >> <http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2007May/0018.html> >> >> >> Any discussion about whether this is a legitimate thing to try to do >> should be added to that thread. This thread is for a possible solution >> that meets the perceived need. >> >> >> CURRENT SYNTAX >> >> There are two current technique for specifying an object that is a >> resource. They are to use @href on elements that are not anchor tags, >> and the second is to use a link element. >> >> The first, using '@href everywhere': >> >> <div about="http://joost.com/some-film"> >> <div property="dc:title">A film</div> >> <div property="dc:description"> >> Some notes on the film >> </div> >> <span rel="dc:subject" href="http://film-vocab/horror">Category: >> Horror</span> >> </div> >> >> There has been some pushback on this technique. >> >> The second is to use a link element: >> >> <div about="http://joost.com/some-film"> >> <link rel="dc:subject" href="http://film-vocab/horror" /> >> <div property="dc:title">A film</div> >> <div property="dc:description"> >> Some notes on the film >> </div> >> <span>Category: Horror</span> >> </div> >> >> In terms of use in current browsers, we're finding that context >> information is lost when using 'link' in the body of the document, so >> this doesn't look like it will work. Obviously the elements could be >> added to <head> with an @about, but that makes things quite difficult >> to manage. >> >> >> @HREF EVERYWHERE >> >> In my view the idea that authors will be confused by having '@href >> everywhere' is not as big a problem as has been posed. However, I'm >> always of the view that if we can find an alternative solution that >> does as good a job as a solution that people aren't comfortable with, >> why not just use it. In this case, I think there is an alternative >> solution that is in some ways better than '@href everywhere'. >> >> >> A SHORT HISTORY OF @RESOURCE >> >> In my earliest drafts of RDFa I used attributes for subject, predicate >> and objects, and the one for objects that were resources was >> @resource. However, this was never satisfactory, because it meant that >> information would often be duplicated--once for a clickable link, and >> once for a statement--and it was the big thing that Ben Adida insisted >> we should solve. So, after a great deal of juggling things around, I >> stumbled upon the fact that @rel and @rev could be used on anchor >> tags--maybe I was the only one who didn't, but I had not known that >> that--and so it became pretty clear that HTML already gave us what we >> needed and we could use @href instead of @resource. This seemed to >> meet Ben's crucial requirement that we should only have to express the >> URI once, and so 'bridge the clickable and semantic webs'. :) >> >> Now, since XHTML 2 had previously added a new feature that @href could >> be used on any element in a document, to create a navigable link, it >> seemed obvious that all we had to do was drop @resource, and replace >> it with @href. >> >> However, non-XHTML 2 browsers actually have a tough time turning @href >> on a span into a clickable link, and although it can be done with some >> script, we don't get that out of the box. This means that we can have >> @href attributes in a document that are not clickable links, and there >> has been some argument that using @href on non-anchor elements could >> confuse people. >> >> >> PROPOSAL >> >> My proposal would therefore be to still _allow_ @href anywhere, but to >> play this feature down, and point people towards @resource. I feel >> that an RDFa parser should still process @href as an object that is a >> resource, wherever it finds it, so that if it encounters an XHTML 2 >> document, it will still work. >> >> But whilst we still _support_ that feature, in our example code, >> tutorials, and so on, we should instead use the resource attribute to >> express an object that is a resource. Hopefully this way things will >> be clearer to authors. >> >> One way that we could understand this is that @resource is a core RDFa >> attribute, whilst @href is not. When we come to use RDFa in a 'host >> language' we add further rules, and in the case of the host language >> being HTML or XHTML we can say that @href is given the 'RDFa meaning' >> of being equivalent to @resource. >> >> >> SYNTAX >> >> Our previous example would now become: >> >> <div about="http://joost.com/some-film"> >> <div property="dc:title">A film</div> >> <div property="dc:description"> >> Some notes on the film >> </div> >> <span rel="dc:subject" resource="http://film-vocab/horror"> >> Category: Horror >> </span> >> </div> >> >> (I'll leave how the predicate is expressed out of this, but there are >> good arguments for using @property here. I'll start a new thread for >> that.) >> >> Regards, >> >> Mark >> > > > -- Shane P. McCarron Phone: +1 763 786-8160 x120 Managing Director Fax: +1 763 786-8180 ApTest Minnesota Inet: shane@aptest.com
Received on Thursday, 24 May 2007 15:39:34 UTC