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Re: attempting to merge the 'vocab' and 'profile' documents

From: Ivan Herman <ivan@w3.org>
Date: Tue, 09 Mar 2010 10:09:24 +0100
Message-ID: <4B961044.505@w3.org>
To: Ben Adida <ben@adida.net>
CC: Shane McCarron <shane@aptest.com>, Mark Birbeck <mark.birbeck@webbackplane.com>, W3C RDFa WG <public-rdfa-wg@w3.org>

On 2010-3-9 24:33 , Ben Adida wrote:
> On 3/8/10 2:53 PM, Shane McCarron wrote:
>> Flame.  Seriously.
> Now, here's some alternative markup that is enabled by both proposals as
> they stand:
> =========
>  <div about="sunset.jpg" profile="http://creativecommons.org/vocab/">
>     <span property="dc:title">Sunset</span>
>     licensed under a <a rel="license"
> href="http://creativecommons.org/licenses/by/3.0/">CC license</a>.
>     Please provide attribution to <span propery="cc:attributionName">Ben
> Adida</span>.
>  </div>
> =========
> Notice how the CC vocab is effectively defining the "dc" and "cc"
> prefixes. I think that's (a) not very useful and (b) confusing to authors.

Well... yes, this is confusing, but it is confusing because creative
commons did something they should not. If they are a vocabulary
provider, they should not use this mechanism for other vocabularies.

My use case is different, namely that I define a


that would list the namespace declaration for some of the usual
suspects, like dc, cc, rdf, rdfs, sioc, etc and then I can say

<div profile="http://www.example.org/generallyusedvocabularies">
   <span property="dc:title">afadsfa</span>
   <a rel="cc:license" ...>adsfasfas</a>

I find that use case actually way more compelling than the keyword
mechanism. This also means that Yahoo, or Google or Bing can publish
their own preferred vocabularies as RDFa vocabulary files containing
their preferred prefixes and people can choose to use those directly. As
I said in my other mail, I do not believe that the keyword mechanism scales.

> So, maybe you disagree, but I don't think I'm cutting out the really
> good use case, right?
> And as I was writing this out, I just realized that, if we *do* let the
> vocab/profile define prefixes, then we have a big backwards
> compatibility problem:
> =========
>  <div xmlns:cc="FOO">
>    <div profile="BAR">
>       <span property="cc:attributionName">...</span>
>    </div>
>  </div>
> =========
> How does one resolve the 'cc' prefix here?
> If we want to allow @profile to define prefixes, then we have to go one
> of the following routes:
> (1) RDFa 1.0 and RDFa 1.1 parsers may generate *different* triples for
> the same @property, since RDFa 1.0 will ignore @profile.
> (2) RDFa 1.1 must let @xmlns override @profile, even if @xmlns is higher
> up in the DOM tree. Significantly hurts cut-and-paste compatibility when
> @profile is used.
> Neither (1) nor (2) seems like a good idea, and I can't think of an
> alternative route if @profile can define prefixes.

But... the only obligation we have is that RDFa1.1 processors generate
the same triples for current RDFa (ie, RDFa1.0 files). In your example
the usage of @profile is incorrect: it is not a recognized RDFa
attribute in that place. Ie, I do not really see the problem.



> -Ben


Ivan Herman, W3C Semantic Web Activity Lead
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Received on Tuesday, 9 March 2010 09:09:11 UTC

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