player_01.rb

# -*- coding: utf-8 -*-
class Player
  attr_reader :position

  # Cで言うenum的なやつが増えた
  module MOVING_MODE
    NORMAL = 1
    FAST  = 2
  end

  def initialize(position)
    @position = position
    @moving_mode = MOVING_MODE::NORMAL # 状態をインスタンス変数で管理
  end

  def to_fast_mode
    @moving_mode = MOVING_MODE::FAST
  end

  def move(direction)
    # 状態変数を見て動くスピードを変えよう！
    case @moving_mode
    when MOVING_MODE::NORMAL
      speed = 10
    when MOVING_MODE::FAST
      speed = 20
    end

    case direction
    when :up
      @position[:y] -= speed
    when :down
      @position[:y] += speed
    when :left
      @position[:x] -= speed
    when :right
      @position[:x] += speed
    end
  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}