Found a lot of discussion of this, but it didn't seem to suggest a
solution to a common pattern.  The below completely useless example is
modeled after a longer and more useful one in the Agile Web
Development with Rails book (2nd ed):

class Foo
    class << self
          private
          def staticHelperFunction
               12345
          end
    end
    public
    def initialize
         @var = self.class.staticHelperFunction
    end
end
Foo.new.var

Now, the above won't work, obviously.  If I replace the direct call to
staticHelperFunction with instance_eval or send, it will work, but
that feels hackish.   Is there an idiomatic Ruby way to handle this
sort of situation?

In case the goal isn't clear, I want instance (not singleton/class)
methods of a given class to have access to what are essentially helper
functions/subroutines (not other instance methods of the same class)
which are not generally accessible outside of that class.

Doable?