From: Got Ascii <gotascii@...>
Date: 2007-09-22T07:53:09+09:00
Subject: question re: modules and class variable scope

I spent some time trying to find an answer to this but haven't found an
explanation I understand.  Could someone tell me what is going on here:

module Mod
  def self.append_features(base)
    base.extend ClassMethods
    super
  end
  module ClassMethods
    def growl
      puts @@donkey
    end
  end
end

class Animal
  include Mod
  @@donkey = "heyhaw"

  def self.working_growl
    puts @@donkey
  end
end

# uninitialized class variable @@donkey in Mod::ClassMethods
Animal.growl

# works fine
Animal.working_growl

Now, in my limited understanding calling Animal.extend (or base in this
case) ClassMethods should have added growl as a class method to Animal,
equivalent to working_growl in scope (as it turns out self in both
methods is Animal which confuses me even more).  Clearly this is not the
case.  Any help would be appreciated.  Thanks!
-- 
Posted via http://www.ruby-forum.com/.