From: zdennis <zdennis@...>
Date: 2006-04-11T01:15:46+09:00
Subject: Re: Adding in class attribute with a Module

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James Britt wrote:
> 
>> I don't like the sprawl of the concept of
>> an "attribute" of a class-hierarchy-plus-instances-of-those-classes.

I think this is what you are referring to David, and I think it is strange to:

zdennis@lima:~$ irb
irb(main):001:0> class A
irb(main):002:1>   @@myvar = 5
irb(main):003:1>   class << self ; @myvar = 10 ; end
irb(main):004:1> end
=> 10
irb(main):005:0> A.instance_variables
=> []
irb(main):006:0> A.class_variables
=> ["@@myvar"]
irb(main):007:0> a = class A ; class << self ; self ; end ; end
=> #<Class:A>
irb(main):008:0> a.instance_variables
=> ["@myvar"]
irb(main):009:0> a.instance_eval "@myvar"
=> 10
irb(main):010:0> A.module_eval "@@myvar"
=> 5
irb(main):011:0>

It seems like, @@myvar and @myvar should refer to the same reference point. I would expect @@ to signify a class level attribute,
which is actually an instance attribute on the class itself. In my head that makes sense.


> > 
> The 'attribute' concept is messy as it is, but this class use seems to
> be a natural extension of the 'methods that get/set an object variable
> of the same name' idea.
> 

+1

Zach
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