From: 7stud -- <bbxx789_05ss@...>
Date: 2007-11-08T12:03:36+09:00
Subject: Re: instantiating random sub-classes (Dragon, TeethDeer, etc

Charles Lowe wrote:
> Thufir wrote:
>> In Driver, I was considering creating a pseudo-random number between 0
>> and 4, then using case:
>> 
>> case 0
>> AssistantViceTentacleAndOmbudsman
>> 
>> case 1
>> Dragon
>> 
>> case 2
>> DwarvenAngel
>> 
>> case 3
>> IntrepidDecomposedCyclist
>> 
>> case 4
>> TeethDeer
>> 
>> 
>> so that the array of Creatures is filled with a variety of monsters
>> which inherit from Creature.  However, there's gotta be another way.
>> Perhaps ask Creature what its sub-classes are?  Then randomly select
>> from that list/array of monsters?
>> 
>> Here's the code:
>> 
>> C:\code>
>> C:\code>type Driver.rb
>> require 'ArrayOfCreatures'
>> require 'Dragon'                                      #Dragon inherits
>> from Creature
>> require 'Creature'                                    #Subclasses
>> include:  Dragon, TeethDeer, etc
>> 
>> #numOfCreatures=Kernel.rand(3)
>> 
>> puts "\nquantity of creatures:"
>> numOfCreatures = gets.chomp.to_i
>> 
>> 
>> someCreatures = ArrayOfCreatures.new
>> 
>> 
>> 0.upto(numOfCreatures) do |i|
>>         someCreatures[i]=Dragon.new              #what about other
>> types (children/sub-classes) of creature?
>>         print "\n"
>>         print "someCreatures["
>>         print i
>>         print "]:\n"
>>         print someCreatures[i].toString
>> end
>> 
>> 
>> C:\code>
>> 
>> 
>> thanks,
>> 
>> Thufir
> 
> There are two ways to get a list of subclasses. One is to use 
> ObjectSpace#each_object, which is kind of messy, and the other is to use 
> the Creature.inherited hook, to build up the array.


An example of the Class.inherited method:

class Creature
  def Creature.inherited(new_subClass_that_was_defined)
    puts new_subClass_that_was_defined
  end
end

class Monster1 < Creature
end

class Monster2 < Creature
end

class Monster3 < Creature
end

--output:--
Monster1
Monster2
Monster3

You can save those sub Classes in an array:

class Creature
  def Creature.inherited(new_subClass_that_was_defined)
    puts new_subClass_that_was_defined

    if not defined?(@@subs)
      @@subs = []
    end

    @@subs << new_subClass_that_was_defined

  end

  def Creature.subs   #can access @@subs using: Creature.subs
    @@subs
  end
end


require 'creaturefile'
require 'monsterfile'

p Creature.subs


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