Both @rel and @rev on one element in RDFa - Semantic Overflow

Both @rel and @rev on one element in RDFa

2010-02-05T14:23:47Z

Does anyone know whether it's permissible to have both the @rel and @rev attributes on an element in RDFa?

This seems like a slightly odd thing to me if it is allowed since it results in two triples like so:

:a :b :c .
:c :b :a .

Maybe I'm missing it in the specifcation document (it is a long document) but is this expressly forbidden or is this legal syntax?

Answer by jsightler for Both @rel and @rev on one element in RDFa

2010-02-05T21:44:25Z

:a :loves :c .
:c :loves :a .

Does that seem so unusual? I think its both legal, and possibly even expected in many cases.

Answer by Gregg Kellogg for Both @rel and @rev on one element in RDFa

2010-02-16T03:36:31Z

This is essentially the RDFa test 0006, which uses both rev and rel on the same element:

<html xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:foaf="http://xmlns.com/foaf/0.1/">
  <head>
    <base href="http://example.com/test0006"/>
    <title>Test 0006</title>
  </head>
  <body>
    <p>
      This photo was taken by
      <a about="photo1.jpg" rel="dc:creator" rev="foaf:img"
        href="http://www.blogger.com/profile/1109404">Mark Birbeck</a>.
    </p>    
  </body>
</html>

You can try out sample RDFa (or any type of RDF) through my distiller at http://kellogg-assoc.com/distiller, which uses the RdfContext Ruby gem.

Answer by Ivan for Both @rel and @rev on one element in RDFa

2010-02-17T13:41:28Z

The answer is: yes, it is allowed. I agree that it is not widely used but, in a way, it would be more convoluted (spec-wise) to disallow it than to allow it!