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Re: Understanding 'chaining'

From: Ivan Herman <ivan@w3.org>
Date: Sun, 02 Dec 2007 13:06:07 +0100
Message-ID: <47529FAF.5090707@w3.org>
To: Ben Adida <ben@adida.net>
CC: public-rdf-in-xhtml-tf@w3.org

my emotional:-) response is: yes (I mean, I am not opposed:-).

Unfortunately, I am not sure I will have the time to modify my
implementation this coming week (I will have an OWL f2f meeting)...

Hm. Well, wait just a small minute. My 'yes' is for the modified for
chaining stuff. However... can you or Mark give a concise explanation of
the rules for @instanceof in the new setup? It is not 100% clear to me
at this moment.

I do _not_ want to push for my @trel/@trev proposal (in spite of the
Post Scriptum below:-) if we can live without a change on the current
setup. But I just want to have a clear picture in my mind


P.S. Coming back to my @trel/@trev proposal of a few days ago: I just
realized that, with the new/old model, there is perfect symmetry.
@trel/@trev are shorthands, nothing more. Ie, my 'mental' model is:

<span trel="bla:bla" ... > ->
	<span rel="rdf:type" resource="bla:bla" ... >

<span trev="bla:bla" ... > ->
	<span rev="rdf:type" resource="bla:bla" ... >

except that XML does not allow repeating attributes...  Ie,

<div trev="bla:bla">

generates the same 'hanging' triples as a @rev would do with the subject
filled in, possibly, by a resource coming 'back' from the elements below
in the recursive steps. And, if nothing comes back then, well, this
triple will not be completed. Same as for the hanging triples of @rel/@rev)

Ben Adida wrote:
> Hi folks,
> I apologize for my absence these last few days, and though I have many
> explanations, I won't try to use them as excuses :)
> I've spent a while thinking about Mark's proposal, and, after his
> fantastic explanation of the "hanging @rel" model, and Ivan's concise
> summary, I've come to the conclusion that it is a lot more promising
> than my proposal.
> The final argument in favor of Mark's "hanging-@rel" proposal came
> today, as I was writing some RDFa for Creative Commons, and found myself
> with exactly the issue Mark describes as:
>> the following does not do anything useful:
>>   <div about="#me" rel="foaf:knows">
>>     <span about="#mark" property="foaf:lastname>Birbeck</span>
>>   </div>
> which really sucks. Clearly the above needs to mean what Mark's proposal
> makes it mean: that the @rel is hooked onto the @about, and that all is
> well as a result.
> Yes, there are potential complications such as the ones I pointed to in
> my first response to Mark, but I suspect they won't come up often and
> won't really be an impediment to writing or reading RDFa.
> So I'd like to propose that we drop my approach, that we attempt to
> implement Mark's "hanging-@rel" model, including the resulting simpler
> model for @instanceof, and that we see where that takes us ASAP.
> Anyone opposed to this direction?
> -Ben


Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Sunday, 2 December 2007 12:06:23 UTC

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