On 30 Jan 2005, at 02:31, David Powell wrote:
[snip] I meant, although:
XML --[XSLT]--> RDF/XML --[RDF/XML-parser]--> RDF-model
...is an ok reference implementation for demonstrating an RDF mapping, the mapping should be defined in prose, because:
XML --[SAX]--> RDF-model
...would be a lot more efficient and doesn't have so many dependencies. So basically you could navigate the Atom document, and add appropriate statements to an RDF model using the model API.
This sounds very much like saying that it would be easiest if one could interpret Atom directly to be RDF, as proposed by AtomAsRDF.
This can be brought back to the question of how to choose the a model to map Atom to. Here are some initial possibilities:
- choose RSS1.0 or RSS1.1 as the model. Being so flexible it
should be quite easy to map Atom to those flavors of RSS. If
that were possible, then this would be just another way of
saying: anything you can say in Atom you can say in RSS1.x
- create some new model to map atom to: in which case you have
to invent a whole new model and go through all the problems of
working out the consistency of your model that this group has
gone through with Atom.In any case the model you come up will either be:
a. more expressive than Atom: you can express more in the
model than you can in Atom.
b. less expressive: when mapping from Atom to this model you
will loose information
c. isomorphic with Atom: you can map from atom to your model
and back without information loss either way.If your model is a. more expressive or b. then this will not prove to be a good foundation for explaining extensibility clearly, since you will loose information either by mapping to the model or by mapping back to Atom. So really what we require is an isomorphic model. And the isomorphic model that would be the easiest to understand would clearly be the identity model where Atom can be interpreted as RDF.
We are not quite there. There is a mapping from Atom to something very close
to Atom, so close I argue that the Atom working group could easily take
a few steps to make the mapping be the identity map.
Henry Story http://bblfish.net/
