- in the coerce and value functions of the RDF.Term protocol for atoms
- allow them as XSD.AnyURI values
- RDF.Literal.coerce produces XSD.AnyURI literals from them
- allow them in equal_value comparisons with RDF.IRIs and XSD.AnyURIs
It turned out that the costs of separating the XSD datatypes are too high
and probably not worth the effort, since with its limited scope
probably nobody would want to use XSD.ex outside of the RDF.ex context
anyway.
This is required to make date-2 of the SPARQL 1.0 open-world test pass.
Strangely enough, ordering comparisons are nevertheless disallowed
according to date-3 of the same test suite. An implementation which
would allow order comparison is included but uncommented.
