From: Yukihiro Matsumoto <matz@...>
Date: 2007-03-27T11:43:30+09:00
Subject: Re: Class Variables for subclases...

Hi,

In message "Re: Class Variables for subclases..."
    on Tue, 27 Mar 2007 11:37:38 +0900, Sonny Chee <sonny.chee@gmail.com> writes:
|Check out the following:
|
|class A
|  @@anobject = 'green'
|  def fun2
|    @@anobject
|  end
|end
|
|class B < A
|  @@anobject = 'blue'
|  def fun2
|    @@anobject
|  end
|end
|
|puts B.new.fun2    # blue
|puts A.new.fun2    # blue
|
|So it looks like the subclass B is not defining its own class variable
|but reusing A's class variable @@anobject. Is there a different way to
|specify class variables to overcome this issue?

You can use constants-as-class-shared technique.

class A
  Anobject = ['green']
  def fun2
    Anobject[0]
  end
end

class B < A
  Anobject = ['blue']
  def fun2
    Anobject[0]
  end
end

puts B.new.fun2    # blue
puts A.new.fun2    # blue