Modules in Modules

a_state_machine_example.rb

module InitialState 
  def self.state
    :unborn
  end
end 

module Baby
  def self.state
    :feed_me
  end
end 

module Child
  def self.state
    :teach_me
  end
end 

module Teen
  def self.state
    :pay_me
  end
end 

module Adult
  def self.state
    :marry_me
  end
end 

module FinalState 
  def self.state
    :bury_me
  end
end 

module StateMachine

  include InitialState
  include Baby
  include Child
  include Teen
  include Adult
  include FinalState

  def state
    @current_state.state
  end

  def state_transition
    @previous_state = @current_state
    @current_state = @states.shift
  end

  def previous_state
    @previous_state
  end
end
 
class Life 
  include StateMachine
  def initialize
    @states = StateMachine.included_modules.reverse
    @current_state = @states.shift
    @previous_state = nil
  end 
  def resurrect_me
    if state == :bury_me
      "sorry, death is the end"
    end 
  end 
end 

c = Life.new 
puts c.state 
c.state_transition
puts c.state 
# puts c.previous_state 
c.state_transition
puts c.state 
c.state_transition
puts c.state 
c.state_transition
puts c.state 
c.state_transition
puts c.state 
puts c.resurrect_me
p c.class.ancestors