From: Brian Candler <b.candler@...>
Date: 2010-01-09T05:53:34+09:00
Subject: Re: something strange with CLASS and SCOPE

Phillip Gawlowski wrote:
> (Actually, the class instance gets initialized, and not the instance
> variables, strictly speaking.)

It's worth mentioning that a class is itself an object (an instance of 
class Class), and therefore has its own instance variables.

class QQ
  # at this point, the current object ('self') is class QQ itself
  @strange=Array.new

  def report
    # but here, the current object is an instance of class QQ
    # so this is an instance variable in a different object
    puts @strange.class
  end
end

Sometimes the class itself is a useful place to store values:

class QQ
  @count = 0

  def self.count
    @count
  end

  def self.count=(x)
    @count = x
  end

  def initialize
    self.class.count = self.class.count + 1
  end
end

a = QQ.new
b = QQ.new
puts "You have created #{QQ.count} QQ's"
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