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Re: RDFa Lite 1.1 Conformance Section - host language attributes (ISSUE-136)

From: Ivan Herman <ivan@w3.org>
Date: Wed, 25 Apr 2012 11:40:47 +0200
Cc: W3C RDFWA WG <public-rdfa-wg@w3.org>
Message-Id: <D01B8F8D-1265-492F-9777-871356B123A4@w3.org>
To: Alex Milowski <alex@milowski.com>

On Apr 24, 2012, at 18:08 , Alex Milowski wrote:

> On Mon, Apr 23, 2012 at 11:59 PM, Ivan Herman <ivan@w3.org> wrote:
>> Alex,
>> this time I think I do not fully agree with you...
>> Using @rel/@rev would push the source out of RDFa 1.1 Lite. Ie, that should not be allowed. I realize that @rel _may_ be used in HTML5, and that creates an additional issue which Stéphane just noted:
>> https://www.w3.org/2010/02/rdfa/track/issues/135
>> http://lists.w3.org/Archives/Public/public-rdfa-wg/2012Apr/0073.html
> There are a vast majority of HTML documents that use @rel attributes
> on link and anchor elements that do not have RDFa attributes.  If an
> author adds RDFa Lite, those documents, as specified wouldn't be
> considered conformant.  RDFa "borrows" the @rel and @rev attributes
> from HTML and makes them more pervasive.  As such, I would suggest
> that we allow a host language to include them given that they already
> exist and have been used for a long time in HTML.
>> But, if we go along option #1 in that proposal, a value of @rel with only predefined HTML5 value is immaterial from RDFa's point of view.
> Well, I personally rely upon @rel with predefined HTML5 values to
> produce relations between the current document and the target of the
> link regardless of whether it is RDFa Lite or not.  

Actually... in HTML5 that will not work. In HTML5+RDFa only a handful of @rel values are automatically expanded into triples (let us put aside the @vocab issue for now), most of them are ignored. 

> As such, I still
> think the conflict is in RDFa in step 11.  We have a dual use of the
> @property attribute that has unintended consequences in HTML.
> Meanwhile, option #1 doesn't address the existence of the @rel and
> @rev attributes in HTML.  The conformance clause would have to address
> the existence of these attributes.

Yes, indeed, something has to be said on that. (Will try to come up with something somewhere else...)

> Also, to implement option #1, we'd have to disallow generation of
> triples for certain values.  We don't have anything in the algorithm
> nor in the XHTML+RDFa 1.1 specification that does this.  

Indeed, this whole issue is irrelevant for XHTML+RDFa 1.1. But that is a matter of the other thread...


> We'd then
> have to change how terms are processed and allow a list of disallowed
> values to be specified in the context.  I don't find that a pleasant
> solution.  Also, we'd have to specify in Step 11 that if the @rel/@rev
> attributes resulted in no triples, treat them as if they didn't exist.
> We don't have language like that as of right now.
>> _My_ proposal would be to amend that paragraph as follows:
>> [[[
>> It must not use any additional RDFa attributes other than vocab, typeof, property, resource, and prefix; it may also use href and src, in case the Host Language authorizes their usage.
>> ]]]
> That still makes HTML documents non-conformant when they use the @rel
> attribute, as they are likely to do so.
> -- 
> --Alex Milowski
> "The excellence of grammar as a guide is proportional to the paucity of the
> inflexions, i.e. to the degree of analysis effected by the language
> considered."
> Bertrand Russell in a footnote of Principles of Mathematics

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Wednesday, 25 April 2012 09:38:29 UTC

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