A Small Game

rock_paper_scissors.rb

# Rock Paper Scissors is a usual game

class Opponent
  def initialize
    @rps = ['rock', 'paper', 'scissors']
  end

  def play
    @rps[rand 3]
  end
end

class Player
  def initialize
    @opponent = Opponent.new
    @beat = { scissors: 'paper', paper: 'rock', rock: 'scissors' }
    @defeat = { scissors: 'rock', paper: 'scissors', rock: 'paper' }
    @tie = { scissors: 'scissors', paper: 'paper', rock: 'rock' }
  end

  def play_game

    while true

      puts "Rock, Paper or Scissors? (Type exit to quit.)"
      print "> "
      answer = gets.chomp.downcase

      until ['rock', 'paper', 'scissors', 'exit', 'quit'].include? answer
        print "I didn't understand that. Try again: "
        answer = gets.chomp.downcase
      end

      @opp_answer = @opponent.play

      def tell answer
        return "You win!" if @beat[answer.to_sym] == @opp_answer
        return "You lose." if @defeat[answer.to_sym] == @opp_answer
        return "It's a tie!" if @tie[answer.to_sym] == @opp_answer
      end

      puts "The computer played #{@opp_answer}. #{self.tell answer}"
    end
  end
end

Player.new.play_game