Re: .htaccess a major bottleneck to Semantic Web adoption / Was: Re: RDFa vs RDF/XML and content negotiation

Hi Toby,

Yes...of are right. :)

I would say too, that reification is even more long-winded than the
example you have given! You don't have the actual statement "the sky
is blue" in your mark-up, so you need even more RDFa. (You only have
the statement "Mark says 'the sky is blue'".)

But either way, you are right that the whole thing can be spelt out
longhand (as can lists).

The only reason I mentioned it was because for a long time in RDFa we
had a much simpler construct based on occurrences of *nested* <meta>
and <link> properties. However, some browsers thought they were doing
us a favour by moving the <meta> and <link> elements out of the <body>
and into the <head>, which meant it was not possible to implement this
feature in JavaScript. (Obviously server-side RDFa parsers would have
had no problem with it.)

As for lists, the obvious shorthand would be <ol>, <ul>, and <li>, but
it was not obvious what triples should be generated, so we left it.
I.e., your example uses the first/next/nil technique for collections,
but of course there is also the rdf:_1 technique for a list. It wasn't
immediately clear which would be the more useful -- or conformant --
one to generate.



On Mon, Jun 29, 2009 at 2:05 PM, Toby Inkster<> wrote:
> On Mon, 2009-06-29 at 13:30 +0100, Mark Birbeck wrote:
>> If we go back a step, RDFa was carefully designed so that it could
>> carry any combination of the RDF concepts in an HTML document. In the
>> end we dropped reification and lists, because it didn't seem that the
>> RDF community itself was clear on the future of those, but they are
>> both easily added back if the issues were to be resolved.
> RDF reification and lists do *work* in RDFa, they're just a bit of a
> pain to mark up.
> e.g. here's a reification:
> <div xmlns:dc=""
>    xmlns:rdf=""
>    xmlns:db=""
>    typeof="rdf:Statement">
>  <span property="dc:creator">Mark Birkbeck</span> says that
>  <span rel="rdf:subject" resource="[db:Sky]">the sky</span>
>  <span rel="rdf:predicate" resource=""
>      >is</span>
>   <span rel="rdf:object" resource="[db:Blue]">blue</span>.
> </div>
> And an example of a list can be found here:
> --
> Toby A Inkster
> <>
> <>

Mark Birbeck, webBackplane

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Received on Monday, 29 June 2009 13:48:48 UTC