Example of Comparable with Roshambo

roshambo.rb

class Roshambo
  OPTIONS = [:rock, :paper, :scissors]
  WINNERS = OPTIONS.rotate.zip(OPTIONS).to_h
  LOSERS = WINNERS.invert

  attr_reader :value

  include Comparable

  def initialize value = OPTIONS.sample
    unless OPTIONS.include? value
      raise ArgumentError, 'invalid hand'
    end

    @value = value
  end

  def to_s
    @value.to_s.capitalize
  end

  private

  def <=> other
    case other.value
    when value then 0
    when WINNERS[value] then 1
    when LOSERS[value] then -1
    end
  end
end

rock = Roshambo.new :rock
paper = Roshambo.new :paper
scissors = Roshambo.new :scissors

rock == scissors
#=> false
rock > scissors
#=> true
rock < scissors
#=> false
paper < scissors
#=> true