From: Eero Saynatkari <ruby-ml@...>
Date: 2006-01-28T06:33:38+09:00
Subject: Re: class_eval and braces

On 2006.01.28 05:15, Bertram Scharpf wrote:
> Hi,
> 
> as I notice there is a difference between `class_eval' called
> with a block or with a string. Why?

Closures again. The @@m in the block is the @@m of M, 
not the including class. To see this, add a line to
your code: 

> VERSION = :braces
> 
> module M
>   def self.included c
>     case VERSION
>       when :braces then  c.class_eval {@@m = rand}
>       when :quotes then  c.class_eval "@@m = rand"
>     end
>   end
> end
> 
> class C ; @@m = "M" ; def d ; puts @@m ; end ; end
> class D ; @@m = "M" ; def d ; puts @@m ; end ; end
> 
> class C ; puts @@m ; end
> class D ; puts @@m ; end
> C.new.d
> D.new.d
> 
> class C ; include M ; end
> class D ; include M ; end
> 
> class C ; puts @@m ; end
> class D ; puts @@m ; end
> C.new.d
> D.new.d

  module M; puts @@m; end

> Bertram


E