[rdfweb-dev] Re: Syntactic profiling (FOAF document formats)

Leigh Dodds ldodds at ingenta.com
Wed Aug 27 09:48:17 UTC 2003


> > It's no great pain to support this kind of short-cutting of 
> > non-repeated 
> > properties using plain ole XML tools. And as some RDF 
> > libraries (e.g. Jena) 
> > don't give the programmer control over which usage is 
> > generated (AFAIK, anyway) 
> > it would slightly broaden the range of tools and data to play with.
> 
> This is difficult to define in XML Schema. 

But not with RELAX NG:

<element name="foaf:Person" xmlns:foaf="http://xmlns.com/foaf/0.1">
  <choice>
     <element name="foaf:mbox_sha1sum">
       <text/>
     </element>
     <attribute name="foaf:mbox_sha1sum">
       <text/>
     </attribute>
  </choice>
</element>

And you can do it with XML Schema if you incorporate a Schematron 
validation step. There are several tools that support that

> What pupose is served by having a choice anyway? Alternative syntax 
> representations are the problem here, not the solution.

As I noted, some RDF tools don't allow control over whether this form 
of short-cutting is used or not (I'm happy to be proved wrong). So 
allowing it will slightly broaden the range of tools available for processing, 
and the cost in accessing the data is very little from a plain XML 
standpoint. And wasn't one of the original arguments for these syntax 
profiles allowing the greatest possible range of tool support?

Cheers,

L.





More information about the foaf-dev mailing list