Re: RDFa generalization - expressing Microformats

Dan Brickley wrote:
> So these mapping declaration files will need to be protected as
> carefully as RDF namespace docs, to avoid mischief. I assume we'll end
> up with those files living on shared project sites eg. microformats.org
> rather than alongside the rdfa/mf instance data.

Agreed, and is certainly the way I see this working. The Microformats
community would have their XMDP/RDF vocabulary defined somewhere like this:

http://microformats.org/vocab#

or

http://purl.org/uf/vocab#

> I think even having the mapping declared inline in the document could be
> useful, so that it appears once at a higher element in the markup,
> instead of with each occurance. Hard to measure how useful though.

That's our thinking as well. I think we're settling on using @prefix to
do this (see the discussion that was just sent out for details - RDFa
generalization (part 2).

> The ugliest and most common piece of an RDF namespace URI is 'http://'.
> Although I prefer designs that don't privilege any particular URI
> scheme, having some useful shortcuts for users of 'http:' could make our
> markup a lot prettier, without requiring dependency on markup elsewhere
> in the doc, or elsewhere in the Web.

I think this approach let's us get rid of prefix usage when setting
predicates, meaning that we don't need to worry about other types of
namespacing, such as "foaf.tv/name" because you'd just do something like
this:

<body prefix="uf=http://microformats.org/vocab#">

<div typeof="haudio">
   <span property="title">Start Wearing Purple</span> by
   <span property="contributor">Gogol Bordello</span>
   <span property="published" content="20020514">May 14th, 2002</span>
</div>

</body>

Note that in http://microformats.org/vocab#, there are entries defined
in RDFa that generate these triples:

<http://microformats.org/vocab#haudio>
   xhv:reserved
      "haudio" .

<http://microformats.org/vocab#title>
   xhv:reserved
      "title" .

<http://microformats.org/vocab#contributor>
   xhv:reserved
      "contributor" .

<http://microformats.org/vocab#published>
   xhv:reserved
      "published" .

This data is fed to the RDFa parser as "additional reserved words to use
when resolving unprefixed CURIEs", thus generating the following triples
from the original hAudio document listed above:

_:bnode0
   rdf:type
      <http://microformats.org/vocab#haudio> .

_:bnode0
   <http://microformats.org/vocab#title>
      "Start Wearing Purple" .

_:bnode0
   <http://microformats.org/vocab#contributor>
      "Gogol Bordello" .

_:bnode0
   <http://microformats.org/vocab#published>
      "20020514" .

This also means that if people wanted to use "org.example" or
"foo-bar-term", they could, but it would be purely stylistic and not
necessary.

-- manu

-- 
Manu Sporny
President/CEO - Digital Bazaar, Inc.
blog: Bitmunk 3.0 Website Launches
http://blog.digitalbazaar.com/2008/07/03/bitmunk-3-website-launches

Received on Monday, 1 September 2008 17:36:24 UTC