RDF::Query changes to implement contexts. If a context is not-nil, it will be used as an initial filter on queryable in Query#execute. If it is a variable, the filter is on 'true' and a solution matching the context variable is added.
RDF::Query changes to implement contexts. If a context is not-nil, it will be used as an initial filter on queryable in Query#execute. If it is a variable, the filter is on 'true' and a solution matching the context variable is added.

jcoyne/rdf,PerfectMemory/rdf,ruby-rdf/rdf,ninjapanzer/rdf