From: Ed Sinjiashvili <edsin@...>
Date: 2002-04-01T15:17:07+09:00
Subject: re-extending object

Hello, 

I was thinking of using Modules for state modeling:

whailer% cat state_test.rb
module StateA
  def test
    puts "A"
    self.extend StateB
  end
end

module StateB
  def test
    puts "B"
    self.extend StateC
  end
end

module StateC
  def test
    puts "C"
    self.extend StateA
  end
end

class Stateful
  def initialize init_state 
    self.to_state init_state
  end

  def to_state state
    self.extend state
  end
end
            
a = Stateful.new StateA
1.upto 5 do a.test end
whailer%

whailer% ruby state_test.rb
A
B
C
C
C
whailer%

Is it possible to re-extend object - extend it with A, then with B, and then with A again, i.e how do I change my object's inheritance tree dynamically?

--Ed