Re: RDFa and Microformats

Martin McEvoy wrote:

> My response would have been *If* the RDFa community decided that
> Microformats are expressing semantics( which is Acknowledged ) and
> should be somehow ported to RDFa, Microformats do  this using mainly
> using just Class attributes If you are going to "bring them to the  
> fold"
> @class should be added to RDFa as one of its properties.

I think you'll find it's actually a lot more complicated than that.  
Firstly, in microformats different classes have entirely different  
parsing models. In hCard for instance:

   vcard = Look inside for properties.
   fn = Use the contents as the property.
   url = Ignore contents, use the link.
   tel = Look inside for class="type" and class="value".

There are all kinds of special cases. Even in hAudio, which you've  
had a part in designing, and I think is certainly one of the better  
authored microformat specs, there are some parsing oddities. i.e.  
figuring out the type of audio being described (is it an album, is it  
a recording, or is it a track on an album) requires looking for the  
presence of two different properties and deciding based on the  
combination of which exist; rel=tag is handled differently from other  
microformats that use rel=tag (in hAudio the node contents are used,  
in others the URL is used); item opacity and propagation of values  
from parent to child item; etc. Adding all these rules to the RDFa  
specification would massively bloat it.

Parsing existing microformats as part of the RDFa parsing model would  
be massively complicated. And despite the fact that class names are  
often re-used by new microformats, this would not help parsing future  
microformats unless the mfo/hroot question were to be resolved. Such  
an endeavour would not only be bad for RDFa, but would seriously  
constrain the future direction of microformats too.

> All existing Microformated pages,
> Millions of them,  could then potentially become part of RDFa in that
> way almost instantly and So Supporting Microformats in the best way  
> and
> not *breaking* them.

RDFa is "just" a representation of RDF. And microformats can already  
be parsed as RDF - that's the point of GRDDL. Despite the fact that  
XSLT is a horrible, horrible abomination, I think that GRDDL, not  
RDFa, is probably the best hope for bringing microformats into the  
"upper case Semantic Web".

I believe Microformats and RDFa can happily co-exist. They both have  
different syntaxes, but once you've converted them both to the  
abstract RDF model, you can use pretty simple rules to combine the  
data from each. The aim to strive towards should be: different  
syntaxes, separate parsing models, but at the end one data model.

-- 
Toby A Inkster
<mailto:mail@tobyinkster.co.uk>
<http://tobyinkster.co.uk>

Received on Friday, 12 September 2008 09:47:25 UTC