On Thu, Dec 04, 2008 at 10:02:29PM +0900, Daniel Luz wrote:
> As some already mentioned, a Proc would not work, because a default
> value has a very particular binding: it runs in the context of the
> receiver, and can reference all the parameters that come before
> itself.

I suppose it could also (but currently can't) access mandatory parameters
which come after it:

  def foo(x, y=x+z, z) ... end

That way lies madness :-) Although I can't think of sensible use cases where
mandatory parameters are at both ends anyway.