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Re: RDFa 1.1 Issues raised by Google

From: Ivan Herman <ivan@w3.org>
Date: Tue, 25 Oct 2011 16:33:07 +0200
Cc: Manu Sporny <msporny@digitalbazaar.com>, RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <7B7A9397-82B1-4C1F-8428-1D5F5D592136@w3.org>
To: Toby Inkster <tai@g5n.co.uk>

On Oct 24, 2011, at 18:33 , Toby Inkster wrote:

> On Mon, 24 Oct 2011 00:37:45 -0400
> Manu Sporny <msporny@digitalbazaar.com> wrote:
> 
>> RDFa Lite proposal:
>> http://lists.w3.org/Archives/Public/public-vocabs/2011Oct/0093.html
> 
> Specifying RDFa Lite as per above as an authoring subset seems fine,
> but specifying it as a subset for consumers (i.e. you can support RDFa
> Lite by just implementing these attributes and these features) would
> be, as far as I'm concerned, a http://enwp.org/Wrecking_amendment .
> 

Yeah, I can see your point but... I am afraid it will happen nevertheless...

We may have to assess and document which are the 'dangereous' patterns.

Ivan


> This is because you'd end up with certain constructs that would mean
> significantly different things depending on whether it was parsed as
> RDFa 1.1 or RDFa Lite.
> 
> Consider this (admittedly obscure) snippet:
> 
> 	<p typeof="foaf:Person">
> 	  <span property="foaf:name">Alice</span>
> 	  knows
> 	  <span rev="foaf:knows">
> 	    <span property="foaf:name">Bob</span>
> 	  </span>
> 	</p>
> 
> Under RDFa 1.1, this means that something called "Bob" knows a person
> called Alice.
> 
> A theoretical RDFa 1.1 Lite consumer, if it completely ignored the
> presence of @rev, would read it as saying that there exists a person
> who goes by the names of "Alice" and "Bob".
> 
> OK, so maybe you don't like @rev and don't want to honour the
> foaf:knows triple there, but ignoring the fundamental fact that Alice
> and Bob are different people is pretty bad. This kind of inconsistency
> between consuming agents would threaten the viability of RDFa as a
> platform to publishing data.
> 
> As I say, as a subset which authors can choose to follow or not, RDFa
> Lite sounds fine. But if you're targeting this ideas at consumers, it's
> potentially very harmful.
> 
> Some time ago, I wrote a wiki page on which subsets of RDFa it's safe
> to consume. This needs a little update to take into account the changes
> in RDFa 1.1 drafts since last year, but should still be reasonably
> useful.
> 
> http://www.w3.org/2010/02/rdfa/wiki/Subsets
> 
> -- 
> Toby A Inkster
> <mailto:mail@tobyinkster.co.uk>
> <http://tobyinkster.co.uk>
> 
> 


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
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Received on Tuesday, 25 October 2011 14:31:34 GMT

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