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Re: @rel syntax in RDFa (relevant to ISSUE-60 discussion), was: Using XMLNS in link/@rel

From: Philip Taylor <pjt47@cam.ac.uk>
Date: Sun, 01 Mar 2009 18:28:59 +0000
Message-ID: <49AAD3EB.7070304@cam.ac.uk>
To: Ben Adida <ben@adida.net>
CC: HTMLWG WG <public-html@w3.org>, RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>, public-xhtml2@w3.org, "www-tag@w3.org WG" <www-tag@w3.org>
Ben Adida wrote:
> Henri Sivonen wrote:
>> I suggest changing RDFa to use full IRIs instead of CURIEs.
> 
> I appreciate you putting a concrete proposal on the table.
> 
> I believe it is rather arbitrary and in conflict with existing uses in
> HTML4. First, the use of IRIs in @rel is *quite* new, I know of no major
> (or even minor) vocabulary that's deployed this way.

http://philip.html5.org/data/link-rel-rev.txt has a few @rel values 
starting with "http://". One is:
   <link rel="http://schemas.google.com/g/2005#feed" ...>
seemingly defined in 
http://code.google.com/apis/gdata/docs/2.0/reference.html , though 
that's Atom and not HTML. The other cases all look like people got 
confused by the difference between @rel and @href. So it does seem 
reasonable to say that intentional use of IRIs in @rel is unusual.

(The use of prefix-colon values also seems very rare. By far the most 
common is to just make up a string ("nofollow", "apple-touch-icon", 
"dropmenu1", "SQDynButton", etc).)

> And finally, microformats suggest using @profile to interpret their
> @rel's and @class's.

http://philip.html5.org/data/profile-values.txt indicates that pretty 
much nobody (from a roughly random selection of pages across the web) 
uses @profile, except for the one value that's in the default Wordpress 
template. About 130 of the pages use class="vcard" but only 4 seem to 
indicate it in @profile. So the Microformats suggestion to use @profile 
appears to be largely irrelevant in practice.

-- 
Philip Taylor
pjt47@cam.ac.uk
Received on Sunday, 1 March 2009 18:29:37 GMT

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