From: Trans <transfire@...>
Date: 2006-10-26T21:10:19+09:00
Subject: Re: Popularity Contest: Initializing Class-Level Instance Variables


Phrogz wrote:
> Subclassing a class that uses class-level instance variables requires
> that you initialize them for subclasses. Which of the following three
> techniques do you prefer?
>
>
> TECHNIQUE 1 - EXPLICIT INITIALIZATION
> -------------------------------------
> class Alpha
>   @foo = []
>   def self.m1; @foo << rand; end
>   def self.m2; @foo.map{ rand }; end
> end
>
> class Bravo < Alpha
>   @foo = []
> end

Or:

  class Alpha
    @foo = []
    def self.m1; @foo << rand; end
    def self.m2; @foo.map{ rand }; end
    def self.inherited(base)
      base.class_eval { @foo=[] }
    end 
  end
  
  class Bravo < Alpha
  end

T.