- From: José Manuel Cantera Fonseca <jmcf@tid.es>
- Date: Thu, 24 May 2007 17:29:50 +0200
- To: mark.birbeck@x-port.net
- Cc: RDFa <public-rdf-in-xhtml-tf@w3.org>
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 >
Received on Thursday, 24 May 2007 15:35:17 UTC