From: ts <decoux@...>
Date: 2002-04-01T19:42:29+09:00
Subject: Re: re-extending object

>>>>> "E" == Ed Sinjiashvili <edsin@swes.saren.ru> writes:

E> I was thinking of using Modules for state modeling:

 Why you don't use a State pattern ?

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

 In your case a *STUPID* implementation

pigeon% cat b.rb
#!/usr/bin/ruby
class State
   def test
      raise "implement me"
   end
end

class StateA < State
  def test
    puts "A"
    StateB.new
  end
end

class StateB < State
   def test
      puts "B"
      StateC.new
   end
end

class StateC < State
   def test
      puts "C"
      StateA.new
   end
end

class Stateful
   attr_accessor :state
   def initialize init_state
      @state = init_state
   end

   def method_missing(id, *args, &block)
      @state = @state.send(id, *args, &block)
   end
end
            
a = Stateful.new StateA.new
1.upto 5 do a.test end
pigeon% 

pigeon% b.rb
A
B
C
A
B
pigeon% 



Guy Decoux