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re: Relationship to GRDDL, was: rdf in atom

Mark Nottingham wrote:
> ...
> WRT using GRDDL or other out-of-band mechanisms -- the overhead of
> processing GRDDL is IMO not acceptable in some cases,
> and furthermore, it's again not explicit/self-describing.
> ...

Julian Reschke responded:
> ...
> Not sure I follow. Are you concerned by fetching the transform
> separately? By execution time? By the requirement to embed an XSLT
> engine?
> Also I'm not sure what you refer to when you say "not
> explicit/self-describing".
> ...

I am somehow sympathetic to the GRDDL questions asked by Julian Reschke and Henry Story.

The OAI-ORE effort [1] that I am involved in uses Atom with semantics from the ORE Data Model [2] overlaid upon it. That semantic mapping is expressed in a GRDDL crosswalk (Atom to RDF/XML) [3], which achieves something similar to the <at:feedmap> and <at:entrymap> proposed in the I-D. I think it would be good to get a better understanding of when and why an inline approach as proposed by the I-D is more attractive than an out-of-bound approach such as GRDDL. For example, I see the use of an established technology - GRDDL - as a benefit.

The ORE effort also allows for the insertion of RDF triples in Atom, but at this point does so through the insertion of <rdf:Description> elements. An example is at <http://www.openarchives.org/ore/0.9/atom-examples/atom_dlib_maxi.atom>. If the Atom community would decide that the <at:md> approach proposed by the I-D is the way to go, we would certainly recommend it for ORE too. 

Needless to say the ORE effort is very interested in this I-D.

Herbert Van de Sompel

[1] http://www.openarchives.org/ore/toc
[2] http://www.openarchives.org/ore/datamodel
[3] http://www.openarchives.org/ore/atom-grddl

--
Herbert Van de Sompel
Digital Library Research & Prototyping
Los Alamos National Laboratory, Research Library
http://public.lanl.gov/herbertv/