private RdfSourceWrapper BindLogic(SelectableSource source)
{
RdfSourceWrapper sourcewrapper = new RdfSourceWrapper(source, this);
MyLogicFactory logic = new MyLogicFactory();
foreach (RdfFunction f in extFunctions)
logic.registerExternalFunction(
new URIWrapper(f.Uri),
new ExtFuncWrapper(sourcewrapper, f));
query.prepare(sourcewrapper, logic);
return sourcewrapper;
}