[Ara.T.Howard / noaa.gov, 2005-05-04 20.44 CEST]
> hmm - seems like something like that could work alright... but this fails:
[...]
> it's not easy...

If you don't need to distinguish between singleton classes for classes and
normal objects, what's the problem with

def inside?
     self.is_a?(Class) &&
     self.name.empty?
     self.ancestors.first != self
end

?