From: Trans <transfire@...>
Date: 2008-10-23T06:53:33+09:00
Subject: subclass a class in the namespace of the that subclass

Ever get stuck on a problem, and then after staring at it for way too
long, get disgusted b/c there is no way to do it the way you need to
do it, and none of the workable alternatives quite cut it? Well,
that's been my day.

I know it may seem a bit off the wall. But I want to subclass a class
that is also defined in the namespace of the subclass. In other words:

  class X < Y
    class Y
    end
  end

Why do I want to do this? Because my library (X) consists of a few
components, one of them being Y. And I want the end user of the
library to use it by  typing "X.new". Now, X is all but the same as Y,
with only with some minor adjustments.

Unfortunately for me there seems to be no way to do this without Ruby
complaining of a superclass mismatch.

In the end my alternatives appear to be:

1) Use Z instead of X and fake it with X:

  module X
    def self.new
      Z.new
    end
    class Z < Y
    end
  end

2) Delegate Y in X

  class X
    def initialize
      @y = Y.new
    end
    def method_missing ...
  end

#1 sucks because I'm faking it --X isn't really new. And #2 sucks
because it is nothing but a class wrapped around a single instance
variable --a complete waste of resources.

I imagine there is a tricky dynamic coding way to do it, but that will
screw up my RDocs.

Well, I don't see any solution for it --if you have one I'll be
amazed. But at least I got to vent.

T.