Re: RDF should allow XML datatypes

Not sure who this is addressed to, but it mostly deals with syntax,
so I'll reply.  The RDF concepts and abstract syntax editors may also
have some comments I expect.


>>>Jonathan Borden said:
> 
> RDF datatyping should allow the form:

This is asking for a feature by showing you think it should be
implemented, which isn't a good way to approach it.

You are obliquely refering to the requirements of WebOnt I assume,
and in particular, 4.3 as recorded in:
  http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I4.3-Structured-Datatypes

which I note, says: "Status Postponed"


> http://example.org#foo http://example.org#prop "<this>is some structured XML</this>"^^http://example.org/SomeSchema#myType
> 
> where http://example.org/SomeSchema#myType identifies the XML datatype:
> element this{text}
> 
> Similarly RDF/XML should provide for:
> 
> <rdf:Description rdf:about="http://example.org#foo">
>     <ex:prop rdf:datatype="http://example.org/SomeSchema#myType">
>             <this>is some structured XML</this>
>     </ex:prop>
> </rdf:Description>
> 
> 
> 1. There is no compelling reason to prohibit this given the current RDF
> datatyping solution for which this is a minor modification to the syntax.

As editor of the RDF/XML spec, I feel this is not a minor syntax
change and in particular does not match our abstract syntax for
datatyped literals, so would require a change to RDF.


> 2. Allowing this will be very useful for OWL which needs to deal with
> structured datatypes

"Postponed"?  Plus you can still do it with the rdf:datatype, since
it allows any lexical form to be given as a string, that includes XML
infosets serialised to a string.


> 3. Despite the face that XML Schema does not _automatically_ provide for
> URIs for schema particles, when it does in the future, and when one
> explicitly assigns a URIref to an XML Schema particle, this solution will be
> most useful.

Knowing that such W3C XML Schema (WXS) datatypes would have URIs,
that's one reason why we use them to identify the datatypes, the
atomic ones in particular.

> 3a. The failure of XML Schema to provide URIs should not arbitrarily limit
> RDF datatypes. Indeed such a failure will arbitrarily limit future RDF and
> XML Schema datatype interoperability
> -- 2 specifications would need to be fixed not just one -- both the current
> XML Schema REC and the new RDF REC
> -- there wouldn't be so much reason for XML Schema to provide URIs for
> complex datatypes since RDF wouldn't be able to use them.

Not sure why you are telling RDF Core this - it's more of a criticism
of WXS, which you should address to the appropriate WG.

RDF and the XML syntax RDF/XML does allow any datatype that has a URI
for its terms and a lexical form that is a string.  A dataype that
has no URI isn't going to work in RDF.

That lexical form could be a serialisation of a structured form such
as vCard, iCalendar, or even XML.  The latter is how you can do
structured XML datatype values in RDF/XML (as revised) if you wish.

Dave

Received on Tuesday, 29 October 2002 10:00:48 UTC