shouldn't there be a version of Module#included_modules or #ancestors
which actually returns the uncrippled list of included modules at the
immediate level? Current versions of those two methods only lists them
recursively and don't count repeated inclusion. I want the stuff that's
really written in the Module, not some predigested version.

also I'd like a method to find whether an object has a singleton class,
without creating one. This is not possible because Object itself doesn't
have an #extended_modules, though it has a #singleton_methods.

matju