Ruby RPG:生物特征的未定义方法

Question

好的，我以前用其他语言(也就是python)写过一些简单的RPG，所以我决定试着用ruby写一个。所以，今天早上，我坐下来，输入了战斗力学的基础知识，制作了一些生物，开始了这个故事。然而，由于某些原因，当我试图运行程序时，我得到了这个错误：

herosquest.rb:67: undefined method 'traits' for Creature::Hero:Class (NoMethodError)

我回顾了一下代码(我将在最后提供完整的代码)，在第26到55行找到了定义，这正是它应该在的位置。

class Creature
  # Creature attributes are used to determine the outcome of combat.
  traits :life, :strength, :charisma, :weapon
  attr_accessor :life, :strength, :charisma, :weapon
  #New class methods for hp, str, char, wep
  def self.life( val )
    @traits ||= {}
    @traits['life'] = val
  end

  def self.strength( val )
    @traits ||= {}
    @traits['strength'] = val
  end

  def self.charisma( val )
    @traits ||= {}
    @traits['charisma'] = val
  end

  def self.weapon( val )
    @traits ||= {}
    @traits['weapon'] = val
  end
    #initialize sets defaults for each attr
  def initialize
    self.class.traits.each do |k,v|
      instance_variable_set("@#{k}", v)
    end
  end
end

为什么它不起作用？

下面是剩余的代码，如果有用的话。注意:当我复制我的代码时，一些缩进搞砸了。它比看起来要整洁得多。

#CREATURE MECHANICS
    #Create critters. Make them do stuff.
class Creature
  def self.metaclass; class << self; self; end; end
  def self.traits( *arr )
    return @traits if arr.empty?
    attr_accessor( *arr )
    arr.each do |a|
      metaclass.instance_eval do
        define_method( a ) do |val|
          @traits ||= {}
          @traits[a] = val
        end
      end
    end
    class_eval do
      define_method( :initialize ) do
        self.class.traits.each do |k,v|
          instance_variable_set("@#{k}", v)
        end
      end
    end
  end


class Creature
    # Creature attributes are used to determine the outcome of combat.
  traits :life, :strength, :charisma, :weapon
  attr_accessor :life, :strength, :charisma, :weapon
  #New class methods for hp, str, char, wep
  def self.life( val )
    @traits ||= {}
    @traits['life'] = val
  end

  def self.strength( val )
    @traits ||= {}
    @traits['strength'] = val
  end

  def self.charisma( val )
    @traits ||= {}
    @traits['charisma'] = val
  end

  def self.weapon( val )
    @traits ||= {}
    @traits['weapon'] = val
  end
    #initialize sets defaults for each attr
  def initialize
    self.class.traits.each do |k,v|
      instance_variable_set("@#{k}", v)
    end
  end
end




#CREATURE TYPES
  #Hero
    #Our brave Hero! Chosen by the gods! Mighty slayer
    #of beasts! Also, broke. Which is why he's hunting
    #a dragon. Poor, foolish mortal...
class Hero < Creature
  traits :bombs, :arrows, :money

  life 10
  strength 4
  charisma 4
  weapon 4
  bombs rand(3..10)
    arrows rand(15..100)
    money rand(0..25)               #Should be used with Traders for buying stuff

  #Bow. Needs arrows. Duh. Hero should start with, say, 50?
  def ^( enemy )
    if @arrows.zero?
      puts "[Twang. Your imaginary arrow, alas, fails to slay the creature. Or have any effect at all. Moron.]"
      return
    end
    @arrows -= 1
    fight( enemy, rand(0+((charisma+(0..4))*2)))    #Zero means you missed
  end
end

  #The hero's sword, given to him by the gods.
    #Unlimited uses. Also, shiny.
  def /( enemy )
    fight( enemy, rand(4+weapon+(strength*2)))
  end

    #Trading. Ah, commerce! Doesn't quite work yet.
    #Need a way to make sure money stays positive,
    #and some sort of way to make sure you can't
    #cheat the poor trader out of his goods.
    def trade( enemy )
        if @money.zero?
            puts "[ The trader ignores you. You need money.]"
            return
        else puts "[What do you want to buy?\n Arrows = 10 for 2 coins\n Bombs = 5 for 5 coins]"        #Should add new weapons someday
            purchase = gets.chomp
            if purchase == "Arrows"
                puts "[You buy 10 arrows for 2 coins]"
                @arrows += 10
                @money  -= 2
            elsif purchase == "Bombs"
                puts "[You buy 5 bombs for 5 coins]"
                @bombs += 5
                @money  -= 5
    end
end     

  #Mmm, tasty lembas. Elvish waybread. One small
    #bite is enough to fill the stomach of a grown man.
  def %( enemy )
    lembas = rand( charisma )
    puts "[Tasty lembas gives you #{ lembas } life.]"
    @life += lembas
    fight( enemy, 0 )
  end

  #Bombs. They explode. Hopefully, far away from you.
  def *( enemy )
    if @bombs.zero?
      puts "[You light your finger on fire instead of the fuze. Then, you realize you're out of bombs.]"
            @life -= 1
      return
    end
    @bombs -= 1
    fight( enemy, rand(weapon+(2..25)))
  end
end


#Man
    #Doesn't do much. Stands around and says boring things. Well, someday, anyway...
class Man < Creature
    traits :chat        #Will eventually say random stuff about the weather or whatever.

  life 4
  strength 2
  charisma 4
  weapon 1          
end


#Woman
    #Like Man. Except she smells nicer.
    #Oh, and she's got a frying pan...
    #Looks fierce.
class Woman < Creature
  life 4
  strength 2
  charisma 8
  weapon 4          
end


#Trader
    #Hangs around taverns and pushes
    #useless stuff on passers-by.
class Trader < Creature
  traits :bombs, :arrows, :money

  life 4
  strength 4
  charisma 16
  weapon 10         #Armed and dangerous. Sort of...
  bombs rand(0..100)
    arrows rand(0..500)
    money rand(100..2500)
end


#Monkey
    #Pain in the butt. Travels in packs. Makes
    #faces and throws bananas.
class Monkey < Creature
  life 8
  strength 5
  charisma 11
  weapon 2          #Beats you with its cute little fists.
end


#Cow
    #Cows won't attack you unless you hit them, or try to ride them, 
    #or make fun of them for chewing cud.
    #Also, they don't like it when people stare
    #at their udders. It makes them uncomfortable.
class Cow < Creature
  life 18
  strength 15
  charisma 2        #It's a cow, not a rocket scientist
  weapon 3
end


#Deer
    #The deer is not as timid as it appears. Serves you right
    #for picking on a poor, "helpless" creature. Jerk.
class Deer < Creature
  life 30
  strength 22
  charisma 5
  weapon 15
end


#Biker
    #Found on paths. Rides a bike.
    #Not *super* tough, but should be 
    #strong enough to make you fear
    #for your life.
class Biker < Creature
  life 34
  strength 10
  charisma 4        #They aren't very bright...
  weapon 8
end


#Angel
    #Heavenly host. "Information: Kill"
    #Seriously, don't screw around with these guys.
class Angel < Creature
  life 85
  strength 8
  charisma 60       #Seriously smart, since it's
  weapon 25                 #secretly a robot.
end


#Tentacle
    #Found in lakes by throwing things ala Merry and Pippin.
    #NOTE: Should include this in the first scene with a lake:
        #"I am afraid of the pool. Don't disturb it!"
    #Should preferably be said by a smallish man, muttering about
    #"My precious," Mordor, and someone called Sam.
class Tentacle < Creature
  life 9
  strength 3        #Not strong, but there's a lot of them.
  charisma 4
  weapon 8
end


#Watcher in the Water
    #Found after killing a bunch of tentacles.
    #Should be tough enough to scare you off,
    #but weak enough that you won't die
    #instantly.
class Watcher_in_the_Water < Creature
    life 250
  strength 10
  charisma 35
  weapon 4          #I don't want him to be too powerfull
end


#Dragon
    #Will totally kill you to death. A lot.
    #Final boss type thing. Surrounded
    #by his hoard of glittering treasure.
        #Oooh, shiny...
class Dragon < Creature
  life 500     # tough scales
  strength 95  # bristling veins
  charisma 65  # toothy smile
  weapon 157   # fire breath
end




#COMBAT MECHANICS
  #Hitting in combat
  def hit( damage )
    p_up = rand( charisma )
    if p_up % 9 == 7
      @life += p_up / 4
      puts "[#{ self.class } magic powers up #{ p_up }!]"
    end
    @life -= damage
    puts "[#{ self.class } has died.]" if @life <= 0
  end

    #Turn in combat
  def fight( enemy, weapon )
    if life <= 0
      puts "[#{ self.class } is dead, Jim. You can't fight!]"
      return
    end

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

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



#PLACES, EVENTS, & STORY
    #First, generate the Player
h = Hero.new
    #Determine player name and gender
    print "What is your name, adventurer?\n"
        name=gets.chomp.to_s
    print "#{name}, are you male or female?\n"
        gender=gets
    print "\n"


    #player chooses his/her class
until heroclass = (1..3)
print"What class do you want?\n(1 for Scout, 2 for Fighter, or 3 for Ranger)\n"
heroclass = gets.to_i
        if heroclass == 1
            heroclass = "Scout"
            Hero.charisma = charisma + 3
            Hero.strength = strength - 1
            Hero.weapon = weapon + 1
            Hero.arrows = arrows + 50
            print"Scouts are quick and intelligent, but they are a bit weak.\nTheir prefered weapon is the bow.\n"
    break
        elsif heroclass == 2
            heroclass = "Fighter"
            Hero.strength = strength + 3
            Hero.charisma = charisma - 3
            Hero.weapon = weapon + 3
            Hero.life = life + 5
            print"Fighters are skilled at close combat, and their endurance is unmached by lesser mortals.\n(They aren't very bright though...)\nTheir prefered weapon is the sword\n"
    break
        elsif heroclass == 3
            heroclass = "Ranger"
            Hero.strength = strength - 1
            Hero.charisma = charisma + 2
            Hero.life = life + 2
            Hero.bombs = bombs + 5
            Hero.weapon = weapon + 2
            print"Rangers are highly skilled, but not as strong as fighters or as agile as scouts.\nThey fight well with all weapons, but they particularly enjoy blowing stuff up.\n"
    break
        else print "Please enter a valid class number."
end
print "Welcome, #{name}, the #{gender} #{heroclass}, Chosen Hero of the gods!\n"
print "The disembodied voice you are now hearing is your Spirit Guide"
end

Answer 1

当我尝试运行你的代码时，我得到了这个错误

so_question.rb:28:in `<class:Creature>': undefined method `traits' for Creature::Creature:Class (NoMethodError)
    from so_question.rb:26:in `<class:Creature>'
    from so_question.rb:3:in `<main>'

因为在Creature类中有一个名为Creature的类，而traits是Creature上的类方法，而不是Creature::Creature上的类方法。