player_04.rb

# -*- coding: utf-8 -*-
module Movable
  def position(position=nil)
    return {:x=>@x, :y=>@y} unless position
    
    @x = position[:x] 
    @y = position[:y]
  end

  def set_position_or_player(position)
    position (position.is_a?(Movable) ? position.position : position)
  end

  def set_ratio(x, y)
    @x_ratio = x
    @y_ratio = y
  end

  def move(direction)
    case direction
    when :up
      @y -= 10 * @y_ratio
    when :down
      @y += 10 * @y_ratio
    when :left
      @x -= 10 * @x_ratio
    when :right
      @x += 10 * @x_ratio
    end
  end
end

class NormalPlayer
  include Movable
  def initialize(position)
    set_position_or_player position
    set_ratio 1, 1
  end
end

class FastPlayer < NormalPlayer
  include Movable
  def initialize(position)
    super
    set_ratio 2, 2
  end
end

class KaniPlayer < NormalPlayer
  include Movable
  def initialize(position)
    super
    set_ratio 4, 0.5
  end
end

class NechigaePlayer < NormalPlayer
  include Movable

  def position(position=nil)
    return {:x=>@y, :y=>@x} unless position
    
    @x = position[:y] 
    @y = position[:x]
  end
end

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

player = FastPlayer.new player
player.move :down
p player.position #=> {:x => 100, :y => 110}

player = KaniPlayer.new player
player.move :up
player.move :left
p player.position #=> {:x => 60, :y => 105}

player = NechigaePlayer.new player
player.move(:up)
p player.position # => {:x => 50, :y => 105}