From: Alex Young <alex@...>
Date: 2007-08-17T04:24:31+09:00
Subject: Re: Does singleton variables have any meaning ?

Phrogz wrote:
> On Aug 16, 10:25 am, Alex Young <a...@blackkettle.org> wrote:
>> Arno J. wrote:
>>> class A
>>>   @class_instance_variable
>>>   class << self  #or class << A
>>>     @singleton_variable # <- Can this be used/called elsewhere ?
>>>     def some_method
>>>       @class_instance_variable
>>>     end
>>>   end
>>> end
> 
> 
>> class A
>>    class << self
>>      @singleton_variable
>>      attr_accessor :singleton_variable # <----- N.B.
>>    end
>> end
>> irb(main):035:0> A.singleton_variable = :foo
>> => :foo
>> irb(main):037:0> A.singleton_variable
>> => :foo
> 
> Your accessor method there is referencing a new class-level instance
> variable, that is in a different scope than your (no-op)
> @singleton_variable line there.
> 
> irb(main):001:0> class A
> irb(main):002:1>   @foo = 1
> irb(main):003:1>   class << self
> irb(main):004:2>     @foo = 2
> irb(main):005:2>     attr_accessor :foo
> irb(main):006:2>   end
> irb(main):007:1> end
> => nil
> irb(main):008:0> A.foo
> => 1
> 
> 
You're absolutely right.  Got myself confused in a maze of twisty 
passages.  Sorry for the noise :-)

-- 
Alex