Doesn't _why have an interesting approach of this problem? I forget
what it is called. I think he basically "objectified" the whole of
Ruby so it was reusable.

Also, I recently posted this to core (doubt it would ease the
implementation issues however):

Would it be possible to do selector namespaces on a file basis? That
is to say, load a library such that it would only apply to the
immediate file and no other? For example lets say I have:

  # round.rb
  class Float
    def round
      0
    end
  end

  # foo.rb
  n = 1.23
  puts n.round

  #boo.rb
  selector_require "round"   # hypothetical
  require "foo"
  n = 1.234
  puts n.to_f

running boo.rb, we'd get:

  1
  0

The 1 comes from foo.rb, but the 0 from boo.rb because we "selectively
loaded" round.rb.

I've never been satisfied with block-oriented approaches often cited.
Is this perhaps a more useful approach?  Or does this have problems of
it own?

T.