Re: RDFa generalization - expressing Microformats

Manu Sporny wrote:
> Hey guys,
> 
> Shane and I talked a bit about a general mechanism of extending the
> default prefix mapping in RDFa:
> 
> http://www.rdfa.info/wiki/RDFa_Profiles


> [21:24:02] … how do you specify the default prefix mapping?
> [21:24:09] … That's the most important thing...
> [21:24:27] Shane McCarron: lol... you cannot.  we dont permit it to be
> changed in RDFa
> [21:24:38] Manu Sporny: yeah, see... that's the issue.
> [21:24:50] … and that's what's going to be the major push-back from the
> Microformats community.
> [21:25:03] … so, forget about changing the default prefix mapping.

Interesting idea. I certainly think that being able to avoid ns prefixes 
in some cases is important. But putting the mappings into another file, 
I fear could create fragility. It makes copy/paste of data a lot more 
probabilistic. In the majority of cases we'll have the same prefix for 
the same URI. In the remainder of cases, it will probably be a related 
URI ('dc' mapping to some Dublin Core URI or other). This creates 
another single point of vulnerability whereby the meaning of the 
documents can be radically switched by changing a few chars in another 
doc. 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.

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.

My preference instead would be to consider prettier URI schemes and syntax.

What would it take to be able to write "<span 
property="tv.foaf/name">John Smith</span>", based on a website at 
http://foaf.tv/? And have the RDFa environment supply that default 
prefix of http:// ? (i just bought 'foaf.tv', to make this example 
non-fictional; the '.info' had gone). Authors who want their properties 
to be super-memorable could invest in domain names and apache config 
that make these things both short and dereferencable. Java-style naming 
has cropped up again and again on the WHATWG list as something that 
compares favourably to XML namespace syntax. The main difference is 
simply those 7 chars at the start of each namespace.

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.

cheers,

Dan


--
htp://danbri.org/

Received on Monday, 1 September 2008 08:27:44 UTC