#from why's (poignant) guide to Ruby

    # The guts of life force within Dwemthy's Array
class Creature

    # Get a metaclass for this class
  def self.metaclass; class << self; self; end; end

    # Advanced metaprogramming code for nice, clean traits
  def self.traits( *arr )
    return @traits if arr.empty?
 
       # 1. Set up accessors for each variable
    attr_accessor *arr

       # 2. Add a new class method to for each trait.
    arr.each do |a|
      metaclass.instance_eval do
        define_method( a ) do |val|
          @traits ||= {}
          @traits[a] = val
        end
      end
    end
  
       # 3. For each monster, the `initialize' method
       # should use the default number for each trait.
    class_eval do
      define_method( :initialize ) do
        self.class.traits.each do |k,v|
          instance_variable_set("@#{k}", v)
        end
      end
    end
  end

       # Creature attributes are read-only
  traits :life, :strength, :charisma, :weapon
end

p Creature.public_instance_methods(false)

class Dragon < Creature
  life 1340     # tough scales
  strength 451  # bristling veins
  charisma 1020 # toothy smile
  weapon 939    # fire breath
end

class Creature
 
    # This method applies a hit taken during a fight.
  def hit( damage )
    p_up = rand( charisma )
    if p_up % 9 == 7
      @life += p_up / 4
      puts "[#{ self.class } magick powers up #{ p_up }!]"
    end
    @life -= damage
    puts "[#{ self.class } has died.]" if @life <= 0
  end

    # This method takes one turn in a fight.
    # This method takes one turn in a fight.
  def fight( enemy, weapon )
    if life <= 0
      puts "[#{ self.class } is too dead to fight!]"
      return
    end

      # Attack the opponent
    your_hit = rand( strength + weapon )
    puts "[You hit with #{ your_hit } points of damage!]"
    enemy.hit( your_hit )

      # Retaliation
    p enemy
    if enemy.life > 0
      enemy_hit = rand( enemy.strength + enemy.weapon )
      puts "[Your enemy hit with #{ enemy_hit } points of damage!]"
      self.hit( enemy_hit )
    end
  end
end

class DwemthysArray < Array
  alias _inspect inspect
  def inspect; "#<#{ self.class }#{ _inspect }>"; end
  def method_missing( meth, *args )
    answer = first.send( meth, *args )
    if first.life <= 0
      shift
      if empty?
        puts "[Whoa. You decimated Dwemthy's Array!]"
      else
        puts "[Get ready. #{ first.class } has emerged.]"
      end
    end
    answer || 0
  end
end

class Rabbit < Creature
  traits :bombs
  life 10
  strength 2
  charisma 44
  weapon 4
  bombs 3

    # little boomerang
  def ^( enemy )
    fight( enemy, 13 )
  end

    # the hero's sword is unlimited!!
  def /( enemy )
    fight( enemy, rand( 4 + ( ( enemy.life % 10 ) ** 2 ) ) )
  end

    # lettuce will build your strength and extra ruffage
    # will fly in the face of your opponent!!
  def %( enemy )
    lettuce = rand( charisma )
    puts "[Healthy lettuce gives you #{ lettuce } life points!!]"
    @life += lettuce
    fight( enemy, 0 )
  end

    # bombs, but you only have three!!
  def *( enemy )
    if @bombs.zero?
      puts "[UHN!! You're out of bombs!!]"
      return
    end
    @bombs -= 1
    fight( enemy, 86 )
  end
end

class ScubaArgentine < Creature
  life 46
  strength 35
  charisma 91
  weapon 2
end

class IndustrialRaverMonkey < Creature
  life 46
  strength 35
  charisma 91
  weapon 2
end

class DwarvenAngel < Creature
  life 540
  strength 6
  charisma 144
  weapon 50
end

class AssistantViceTentacleAndOmbudsman < Creature
  life 320
  strength 6
  charisma 144
  weapon 50
end

class TeethDeer < Creature
  life 655
  strength 192
  charisma 19
  weapon 109
end

class IntrepidDecomposedCyclist < Creature
  life 901
  strength 560
  charisma 422
  weapon 105
end

$dwary = DwemthysArray[IndustrialRaverMonkey.new,
           DwarvenAngel.new,
           AssistantViceTentacleAndOmbudsman.new,
           TeethDeer.new,
           IntrepidDecomposedCyclist.new,
           Dragon.new]