deep_freezing.rb

module DeepFreezing
  # „Deep freezes“ the array, that is:
  # - if the element responds to deep_freeze itself,
  #   like Array and Hash should, call it.
  # - if the element responds to freeze, call it
  # - freeze self
  #
  # ==== Returns
  # self
  #
  # ==== Considerations
  # Circular references are not resolved and might result in a deadlock,
  # so don't do that.
  def deep_freeze
    self.each do |element|
      if element.respond_to?(:deep_freeze)
         element.deep_freeze
      elsif element.respond_to?(:freeze)
         element.freeze
      end
    end

    self.freeze
    self
  end
end