xml-dev - Re: Default Namespaces - why don't they apply to attributes?

[Jonathan Borden <jborden@mediaone.net>]

Ronald Bourret wrote:
> Jonathan Borden wrote:
>
> >Ronald Bourret wrote:
> > >
> > > By the way, I would be really curious to see any applications for
which
> > > knowing of an attribute is "in" a namespace -- as opposed simply
> > >identifying
> > > the attribute -- is important. I can't think of any, but maybe I'm
just
> > > unimaginative.
> >
> >A counter example would be the use of attributes in shorthand RDF
> >serializations.
>
> Could you clarify that a bit? My knowledge of RDF is sketchy at best.
(Does
> RDF assume that unprefixed attributes are RDF-specific rather than
belonging
> to the shorthand elements?)
>

 Clarify RDF? :-))) I've been getting into this recently because I decided
to design our next version healthcare repository around RDF, which I am
using to represent HL7 models.

    The point is that RDF syntax associates namespaces with RDF schemas. The
properties defined by elements or attributes of a particular namespace are
used to define the semantics of such properties. This is easiest to
understand if the properties described by elements, but RDF shorthand allows
such properties to be ascribed using attributes. So, if membership in a
namespace associates semantics, lack of membership in a namespace means that
no semantics are associated with such nodes.

    In fact, the RDF syntax spec makes (IHMO)  the erroneous assumption that
attributes inherit the namespace of the enclosing element (witness the use
of <rdf:y about="..."> rather than <rdf:y rdf:about="...">

To show equivalent uses of element and attribute nodes I will quote an
example from http://www.w3.org/TR/1999/REC-rdf-syntax-19990222/


"
<rdf:RDF>
  <rdf:Description about="http://www.w3.org">
    <s:Publisher>World Wide Web Consortium</s:Publisher>
    <s:Title>W3C Home Page</s:Title>
    <s:Date>1998-10-03T02:27</s:Date>
  </rdf:Description>
</rdf:RDF>

is equivalent for RDF purposes to

<rdf:RDF>
  <rdf:Description about="http://www.w3.org"
       s:Publisher="World Wide Web Consortium"
       s:Title="W3C Home Page"
       s:Date="1998-10-03T02:27"/>
</rdf:RDF>

"

Jonathan Borden
http://www.openhealth.org