On Nov 15, 12:12   宮 
> I think one of Lua's nice features is that all functions are first-
> class functions. That makes it possible to override behavior like
> this:
>
> -- Sample stolen from Wikipedia
> local oldprint = print -- Store current print function as
> oldprint
> print = function(s) - Redefine print function
> if s == "foo" then
> oldprint("bar")
> else
> oldprint(s)
> end
> end
>
> How would you write the above sample using Ruby?
>
> Grtz,
> Francis

module Kernel
  alias_method :old_print, :print
  def my_print(*args)
    old_print "bar"
  end
  alias_method :print, :my_print
end

irb(main):017:0> print "hey"
bar
=> nil

There are several approaches to achieve the same, that's the beauty or
the curse of Ruby :-)

As more complex example, you can check how rubygems replace 'require'
functionality to be able to pick code outside the default $LOAD_PATH.

HTH,
--
Luis Lavena