From: "Jesús Gabriel y Galán" <jgabrielygalan@...>
Date: 2010-10-21T01:10:21+09:00
Subject: Re: Setting Class Variables with Class Method

On Wed, Oct 20, 2010 at 6:04 PM, Thijs De vries <moger777@hotmail.com> wrote:
> Hey guys,
> I was wondering how to set class variables using a class method, for
> example:
>
>  class Foo
>   @@this_works = 'hello'
>   @@this_does_not = self.goodbye
>
>   def self.goodbye
>     return 'goodbye'
>   end
>  end

You can't call a method before defining it. The call to self.goodbye
is executed at that point, but the method goodbye doesn't exist yet.
Try this:

irb(main):001:0> class Foo
irb(main):002:1> def self.goodbye
irb(main):003:2> "goodbye"
irb(main):004:2> end
irb(main):005:1> @@this_works = 'hello'
irb(main):006:1> @@this_does_not = self.goodbye
irb(main):007:1> end
=> "goodbye"
irb(main):011:0> Foo.send(:class_variable_get, "@@this_does_not")
=> "goodbye"

With all the caveats around being sure that you really need class
variables and not class instance variables, and so on...

Hope this helps,

Jesus.