From: Robert Dober <robert.dober@...>
Date: 2010-04-30T20:27:27+09:00
Subject: Re: Switching dynamically between methods (inside modules)

On Fri, Apr 30, 2010 at 12:50 PM, Paul A. <cyril.staff@gmail.com> wrote:
A first, elegant approach suffers from the minor defect that it does not work ;(
module A
  def a; "A" end
end

module B
  def a; "B" end
end

o = Object::new
o.extend A
puts o.a
o.extend B
puts o.a
o.extend A
puts o.a

thus more work is needed
the following code will give you some ideas, I hope

class Module
  def apply obj
    this_mod = self
    methods = instance_methods( false ).map{ | mname | [ mname,
instance_method( mname ) ] }
    p methods
    class << obj; self end.module_eval do
      include this_mod
      methods.each do | name, mthd |
        define_method name do | *args, &blk |
           mthd.bind( self ).call( *args, &blk )
        end
      end
    end
  end
end
module A
  def a; "A" end
end

module B
  def a; "B" end
end

class Object
  def force_extend *mods
    mods.each do | mod |
      mod.apply self
    end
  end
end
o = Object::new
o.force_extend A
puts o.a
o.force_extend B
puts o.a
o.force_extend A
puts o.a

HTH
R.



-- 
The best way to predict the future is to invent it.
-- Alan Kay