From: Morton Goldberg <m_goldberg@...>
Date: 2006-10-02T09:11:00+09:00
Subject: Re: [QUIZ] Story Generator (#96) [SOLUTION] The Quest

Here is my solution, which is based on Dwemthy's Array.

<code>
#! /usr/bin/ruby
# Author: Morton Goldberg
#
# Date: 2006-09-23
#
# Based on the Dwemthy's Array example in Chapter 6 of "why's (poignant)
# guide to ruby".

# This is the story of a rabbit that went on a quest to slay a dragon.
# But before he got to face the dragon, he had to kill a whole bunch
# of other montsters, each much stronger than he. How could a tiny, weak
# rabbit survive against this terrible arary of monsters? Well, he had
# a magick sword, magick lettuce, a few bombs, and -- most  
importantly --
# incredible good luck.

# Abstract class providing the basic behavior of all the creatures in  
the
# story.
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?
       # Set up accessors for each variable
       attr_accessor(*arr)
       # 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
       # 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

    # Damage assessment after taking a hit during fight.
    def hit(damage)
       bonus = rand(magick)
       if bonus % 9 == 7
          @life += bonus
          puts "Protective spell adds #{bonus} to #{self} life force."
       end
       puts "Fighting lowers #{self} life force by #{damage}."
       case
       when damage < 1
          puts "#{self} wasn't touched!"
       when damage < 0.25 * life
          puts "#{self} suffered a minor wound."
       when damage < 0.5 * life
          puts "#{self} was wounded."
       when damage < 0.75 * life
          puts "#{self} was seriously wounded but carries on."
       when damage < life
          puts "#{self} was gravely wounded but survives."
       else
          puts "#{self} dies."
       end
       @life -= damage
    end

    # One participant's attack during one fight turn.
    def attack
       puts attack_description
       damage = rand(strength * life + weapon_force)
       foe.hit(damage)
    end

    # One fight (attack + counter-attack) in a battle.
    def fight
       if life <= 0
          puts "#{self} is too dead to fight."
       else
          puts "#{self} [#{life}] and #{foe} [#{foe.life}] fight."
          # Attack opponent.
          attack if foe.life > 0
          # Opponent's counter-attack.
          foe.attack if life > 0 && foe.life > 0
       end
       self
    end

    def to_s
       self.class.name
    end

    # Description of how an attack was made. Subclasses will often  
override
    # this.
    def attack_description
       "#{self} attacks #{foe} with #{weapon}."
    end

    # Creature default attributes are read-only.
    traits :life, :strength, :magick, :challenge, :weapon, :weapon_force
    # This trait is dynaminc -- don't give it a default value.
    traits :foe
end

# The monsters.

class BogusFox < Creature

    life 50
    strength 0.6
    magick 100
    weapon 'axe'
    weapon_force 20
    challenge "Hail, %s, prepare to die!"

    def attack_description
       "BogusFox " + ["swings", "strikes with"][rand(2)] + " his axe."
    end

end

class Jabberwocky < Creature

    life 100
    strength 0.8
    magick 100
    weapon 'teeth and claws'
    weapon_force 20
    challenge "Ah, a tasty %s!"

end

class DemonAngel < Creature

    life 540
    strength 0.2
    magick 200
    weapon 'black sword'
    weapon_force 20
    challenge "%s, I will eat your soul!"

    def attack_description
       "DemonAngel thrusts " + ["high", "low"][rand(2)] +
       " with her black sword."
    end

end

class ViciousGreenFungus < Creature

    life 320
    strength 0.8
    magick 300
    weapon 'acid spray'
    weapon_force 100
    challenge "No %s has ever left my presence alive."

end

class Dragon < Creature

    life 1340               # really tough hide
    strength 1.0            # big muscles
    magick 1066             # studied with Merlin
    weapon 'blast of flame' # fiery breath
    weapon_force 940
    challenge "A brave %s burns just as well as a timid one."

end

MONSTERS = [
    BogusFox.new,
    Jabberwocky.new,
    DemonAngel.new,
    ViciousGreenFungus.new,
    Dragon.new
].freeze

# The hero.
class Rabbit < Creature

    traits :bombs

    life 25              # no armor or shield
    strength 0.4         # not in great shape
    magick 50            # more than you might expect
    weapon 'boomerang'
    weapon_force 4       # can't handle heavy stuff
    challenge "I fear you not, %s!"
    bombs 3              # quantity

    # Little boomerang. Nearly useless.
    def ^
       self.weapon = Rabbit.weapon
       self.weapon_force = Rabbit.weapon_force
       fight
    end

    # Potent magick sword. Rabbit's Vorpal blade is powered by  
opponent's
    # life force -- a healthier opponent suffers more damage. The  
rabbit's
    # only chance? Well, he has some bombs.
    def /
       self.weapon = 'magick sword'
       self.weapon_force = magick + foe.life
       fight
    end

    # Bombs. Powerful, but rabbits don't have very many.
    def *
       if @bombs.zero?
          puts "Rabbit is out of bombs!"
          return
       end
       @bombs -= 1
       self.weapon = 'bomb'
       self.weapon_force = 1600
       fight
    end

    # Eating magick lettuce casts a spell that improves health.
    def %
       gain = 5 + rand(magick)
       puts "Eating magick lettuce adds #{gain} to Rabbit life force."
       @life += gain
    end

end

QUOTE = '"'

# The quest.
if $0 == __FILE__
    hero = Rabbit.new
    MONSTERS.each do |a_foe|
       hero.foe = a_foe
       a_foe.foe = hero
       cry = a_foe.challenge % hero
       puts %Q[A #{a_foe} emerges from the gloom and cries out,"#{cry}"]
       puts QUOTE + (hero.challenge % a_foe) + QUOTE
       # Combat! Hero attacks, foe retaliates. Over and over to the  
death,
       # but whose death?
       while hero.life > 0
          if a_foe.life <= 0
             # Victory -- hero munches on magic lettuce.
             hero.%
             break
          end
          # Strike foe with magick sword.
          hero./
          # Throw bomb if foe still major treat.
          hero.* if a_foe.life > 250
       end
       break if hero.life <= 0
    end
    puts "It's over. It's all over."
end
</code>

Regards, Morton