Using the ActiveSupport :: Concern extension

I'm working through CodeSchool RubyBits and I came up with an exercise that I just don't understand: " Make sure the AtariLibrary class only includes the LibraryUtils module and lets ActiveSupport :: Concern take care of loading it. Then refactor the self.included method on LibraryUtils to use the included method .

module LibraryLoader

  extend ActiveSupport::Concern

  module ClassMethods
    def load_game_list
    end
  end
end

module LibraryUtils
  def self.included(base)
    base.load_game_list
  end
end

class AtariLibrary
  include LibraryLoader
  include LibraryUtils
end

      

        
        
        
      

    

Based on the solution (see below) it ActiveSupport::Concern

doesn't seem to care about loading dependencies - you need to include the LibraryLoader inside LibraryUtils.

Can you help me understand what is doing ActiveSupport::Concern

and why it needs to be called via extend

in both modules?

module LibraryLoader
  extend ActiveSupport::Concern

  module ClassMethods
    def load_game_list
    end
  end
end

module LibraryUtils
  extend ActiveSupport::Concern
  include LibraryLoader

  #result of refactoring the self.included method
  included do
    load_game_list
  end
end

class AtariLibrary
  include LibraryUtils
end

      

        
        
        
      

    

Thank!