nice module pattern

This is a really nice pattern for mixins. It allows for clear separation of instance and class methods and allows you to cleanly specify constants and call any class methods you need.

module VarkLogging
  # any constants you want to define
  VARK_LOG_MESSAGE = "vark log!"

  def self.included(base)
    base.send(:include, InstanceMethods)
    base.send(:extend, ClassMethods)
    base.class_eval do
      # any class methods we need to call
      alias_method_chain :add, :vark_logging
    end
  end

  module InstanceMethods
    def add_with_vark_logging(*args)
      puts VARK_LOG_MESSAGE
      add_without_vark_logging(*args)
    end
  end

  module ClassMethods
    def vark?
      true
    end
  end
end

# and if you want to include it without altering the original class definition:
Logger.send(:include, VarkLogging)