From: Paul Brannan <pbrannan@...>
Date: 2002-07-04T03:48:06+09:00
Subject: Re: Mixin class methods

On Thu, Jul 04, 2002 at 03:35:20AM +0900, Steve Tuckner wrote:
> Try "extend" (see below):
> 
> ----------------------------------
> module A
> 	def b(x)
> 		print x, "\n"
> 	end
> end
> 
> class Foo
> 	extend A
> end
> 
> Foo.b(3)        ==> "3"
> ----------------------------------

Be forewarned that class variables used in A are A's class variables,
and not Foo's:

  module A
    def c=(x)
      @@c = x
    end

    def c
      @@c
    end
  end

  class Foo
    extend A
  end

  Foo.c = 3
  p Foo.c #=> 3

  class Bar
    extend A
  end

  p Bar.c #=> 3

I've been bitten by this before.

Paul