From: Joel VanderWerf <vjoel@...>
Date: 2004-06-10T05:24:12+09:00
Subject: Re: accessing class instance variable from instance method

Ara.T.Howard wrote:
> On Wed, 9 Jun 2004 nobu.nokada@softhome.net wrote:
> 
>> Hi,
>>
>> At Wed, 9 Jun 2004 13:10:52 +0900,
>> David Garamond wrote in [ruby-talk:102895]:
>>
>>> I know there might be some cases where you want to share your class vars
>>> with the subclasses, but I usually want a per-class class variables.
>>>
>>> I believe this will change in Ruby2.
>>
>>
>> It was changed in 1.9.
>>
>> -- 
>> Nobu Nakada
> 
> 
> so - does a concept of 'inherited class variable' exist in 1.9 then?  i
> actually use these from time to time...

I did too, until I saw Nobu's note today. I'm going thru all my code and 
replacing inherited class vars with accessors to class vars (protected, 
if need be):

class C
   @history = []
   class << self
     attr_reader :history
   end
end

class D < C
   def foo
     C.history << "D#foo"
   end
end

d = D.new
d.foo
p C.history

I like how "C.history" is explicit about which class's var is being 
accessed, whereas @@ was always ambiguous, depending on initialization 
order.