While searching for Ruby APIs for RDF I came across: ActiveRDF: object-oriented RDF in Ruby "Although most developers are object-oriented, programming RDF is triple-oriented. Bridging this gap, by developing a truly object-oriented API that uses domain terminology, is not straightforward, because of the dynamic and semi-structured nature of RDF and the open-world semantics of RDF Schema.
We present ActiveRDF, our object-oriented library for accessing RDF data. ActiveRDF is completely dynamic, offers full manipulation and querying of RDF data, does not rely on a schema and can be used against different data-stores. In addition, the integration with the popular Rails framework enables very easy development of Semantic Web applications."
"The development of such APIs has been attempted using a statically-typed language (Java) in RdfReactor, Elmo and Jastor. These approaches ignore the flexible and semi-structured nature of RDF data and instead:
1. assume the existence of a schema, because they rely on the RDF Schema to generate corresponding classes,
2. assume the stability of the schema, because they require manual regeneration and recompilation if the schema changes and
3. assume the conformance of RDF data to such a schema, because they do not allow objects with different structure than their class definition.
Unfortunately, these three assumptions are generally wrong, and severely restrict the usage of RDF. A dynamic scripting language on the other hand is very well suited for exposing RDF data and allows us to address the above issues."
The homepage: ActiveRDF. Uses YARS and Redland.
Recent related W3C note: "A Semantic Web Primer for Object-Oriented Software Developers".
Related previous posting: "Scripting the Semantic Web".
Update: It looks like Henry Story noticed ActiveRDF as a good idea too.
Update 2: Brian Gilman recent posting to the Life Science list links to the BioRuby project.