用ruby和haskell，分别写一个21点游戏。

以下是 Ruby 的实现：

class Card
  attr_reader :value

  def initialize(value)
    @value = value
  end
end

class Deck
  FACES = %w[2 3 4 5 6 7 8 9 10 J Q K A].freeze
  SUITS = %w[♠ ♥ ♦ ♣].freeze

  def initialize
    @deck = []
    SUITS.each do |suit|
      FACES.each do |face|
        @deck << Card.new("#{face}#{suit}")
      end
    end
  end

  def shuffle
    @deck.shuffle!
  end

  def draw
    @deck.pop
  end
end

class Game
  POINTS_MAP = { 'J' => 10, 'Q' => 10, 'K' => 10, 'A' => [1, 11] }.freeze

  attr_reader :player_hand, :dealer_hand

  def initialize
    @deck = Deck.new
    @deck.shuffle
    @player_hand = []
    @dealer_hand = []
    2.times do
      @player_hand << @deck.draw
      @dealer_hand << @deck.draw
    end
  end

  def hit
    @player_hand << @deck.draw
  end

  def play_dealer
    while points(@dealer_hand) < 17
      @dealer_hand << @deck.draw
    end
  end

  def points(hand)
    hand.map(&:value).reduce(0) do |sum, value|
      face = value[0..-2]
      if POINTS_MAP.key?(face)
        if POINTS_MAP[face].is_a?(Array)
          sum + POINTS_MAP[face][1]
        else
          sum + POINTS_MAP[face]
        end
      else
        sum + face.to_i
      end
    end
  end

  def winner
    player_points = points(@player_hand)
    dealer_points = points(@dealer_hand)
    if player_points > 21
      :dealer
    elsif dealer_points > 21
      :player
    elsif dealer_points > player_points
      :dealer
    elsif player_points > dealer_points
      :player
    else
      :tie
    end
  end

  def display
    puts "Player has: #{@player_hand.map(&:value).join(', ')}. Total: #{points(@player_hand)}"
    puts "Dealer has: #{@dealer_hand.first.value}, [hidden]"
  end
end

game = Game.new
game.display

while game.points(game.player_hand) < 21
  puts "Do you want to hit or stay? (h/s)"
  input = gets.chomp
  break if input == 's'

  game.hit
  game.display
end

if game.points(game.player_hand) > 21
  puts "You busted!"
else
  game.