Rock, Paper, Scissors

rock_paper_scissors.rb

class RockPaperScissors
  OPTIONS = [:rock, :paper, :scissors]

  include Comparable

  attr_reader :hand

  def initialize
    @hand = OPTIONS.sample
  end

  def <=> other
    mine, yours = self.hand, other.hand
    if mine == yours
      0
    elsif OPTIONS.rotate[OPTIONS.index(mine)] == yours
      -1
    else
      1
    end
  end
end

hand1 = RockPaperScissors.new
#=> #<RockPaperScissors:0x007fc11417f4a8 @hand=:rock>
hand2 = RockPaperScissors.new
#=> #<RockPaperScissors:0x007fc116ac4728 @hand=:paper>
hand1 > hand2
#=> false
hand2 > hand1
#=> true