gistfile1.txt

module M
  def self.included(cls)
    super(cls)
    puts "xyz"
    if cls.class == Module
      cls.extend(M)
    else
      # Quote of the day
      # Kohsuke: "Did I just avoid the harm of eval?"
      # NaHi:    "No, this is actually worse"
      cls.module_eval do
        def self.inherited(p)
          puts "#{self} was subtyped by #{p}"
        end
      end
    end
  end
end

class Alice
  include M
end
class Bob < Alice
  
end