player_03.rb

# -*- coding: utf-8 -*-
class Player
  # それぞれのモードをクラスに切り分けて、
  # それぞれの振る舞いを定義してあげる
  module MovingMode
    class Normal
      def move(direction, position)
        case direction
        when :up
          position[:y] -= 10
        when :down
          position[:y] += 10
        when :left
          position[:x] -= 10
        when :right
          position[:x] += 10
        end
        return position
      end
    end
    class Fast
      def move(direction, position)
        case direction
        when :up
          position[:y] -= 20
        when :down
          position[:y] += 20
        when :left
          position[:x] -= 20
        when :right
          position[:x] += 20
        end
        return position
      end
    end
    class Kani
      def move(direction, position)
        case direction
        when :up
          position[:y] -= 5
        when :down
          position[:y] += 5
        when :left
          position[:x] -= 40
        when :right
          position[:x] += 40
        end
        return position
      end
    end
  end

  attr_reader :position
  def initialize(position)
    @position = position

    # 状態変数じゃなくて、さっき振る舞いを定義したオブジェクトを持たせる
    @moving_mode = MovingMode::Normal.new
  end

  def to_fast_mode
    # ここも
    @moving_mode = MovingMode::Fast.new
  end

  def to_kani_mode
    # ここも
    @moving_mode = MovingMode::Kani.new
  end

  def move(direction)
    # 自分で動くんじゃなくて、持ってるオブジェクトにかわりに仕事させる
    @position = @moving_mode.move(direction, @position)
  end


end

player = Player.new(:x => 100, :y => 100)
player.move(:up)
p player.position # => {:x => 100, :y => 90}

player.to_fast_mode #ここで倍速モードに
player.move(:down)
p player.position # => {:x => 100, :y => 110}

player.to_kani_mode
player.move(:up)
player.move(:left)
p player.position # => {:x => 60, :y => 105}