player_02.rb

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

  # Cで言うenum的なやつ
  module MOVING_MODE
    NORMAL = 1
    FAST  = 2
    KANI  = 3 #蟹モードが増えた
  end

  def initialize(position)
    @position = position
    @moving_mode = MOVING_MODE::NORMAL
  end

  def to_fast_mode
    @moving_mode = MOVING_MODE::FAST
  end

  def to_kani_mode
    @moving_mode = MOVING_MODE::KANI
  end

  def move(direction)
    case @moving_mode
    when MOVING_MODE::NORMAL
      x_speed = 10 # かにモードとの整合性のために
      y_speed = 10 # 無駄な変更が加えられている
    when MOVING_MODE::FAST
      x_speed = 20 # FASTモードにも！
      y_speed = 20
    when MOVING_MODE::KANI
      x_speed = 40
      y_speed = 5
    end

    case direction
    when :up
      @position[:y] -= y_speed #ここも書き換えないといけない
    when :down
      @position[:y] += y_speed # ここも
    when :left
      @position[:x] -= x_speed # こk
    when :right
      @position[:x] += x_speed # k
    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}

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