From: Robert Klemme <shortcutter@...>
Date: 2011-01-07T17:26:14+09:00
Subject: Re: Class Initialization?

On Thu, Jan 6, 2011 at 10:43 PM, Gary Wright <gwtmp01@mac.com> wrote:
>
> On Jan 6, 2011, at 3:06 PM, Kedar Mhaswade wrote:
>>
>> And in the process of explaining this, you also indirectly explained one
>> question that was lurking in my mind -- are the
>> attr_readers/writers/accessors available to class variables -- and as I
>> understand it, they are -- by way of your previous class << self
>> construct.
>
> Careful here. The attr* methods are manipulating instance variables and
> not class variables.
>
> instance variables:        private to an object
> class instance variables:  instance variables for an object that
>                           just happens to be a class
> class variables:           nasty, confusing things that have the same name
>                           but not at all the same semantics as 'class
>                           variables' in other languages
>
>
> I think it is very unfortunate that a lot of introductory Ruby texts choose
> to emphasize class variables (@@foo) over plain old instance variables of
> a class (@foo for a class object).

Completely agree.

> If there were one feature I would remove from Ruby (maybe in Ruby 2.0?) it
> would be class variables.

+2

We could start by flagging usage of class variables with a warning -
at least with option -w set.

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/