Optional in Ruby, for https://monospacedmonologues.com/2012/02/the-beast/.

optional.rb

module Optional
  def self.of value
    Of.new value
  end

  def self.absent
    Absent.new
  end

private

  class Of
    def initialize value
      @value = value
    end

    def or defaultValue
      @value
    end
  end

  class Absent
    def or defaultValue
      defaultValue
    end
  end
end