From: Edward Faulkner <ef@...>
Date: 2005-10-26T03:40:21+09:00
Subject: Re: having reference problems

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On Wed, Oct 26, 2005 at 03:02:03AM +0900, shalperin wrote:
> What I am trying to do is refer to an instance variable both by its=20
> index in some array, and also directly.

Having read your example more carefully, I think this does what you
really want.  This works in reverse from my previous example, by
dynamically creating the accessors and storing the variables in an
Array:

class Referenceable
  def self.attr_reference(*attrs)
    @reference ||=3D []
    attrs.each {|a|
      i =3D @reference.size
      define_method(a) do=20
        @reference[i]
      end
      define_method((a.to_s + "=3D").intern) do |val|
        @reference[i] =3D val
      end
      @reference << nil
    }
    def self.refsize
      @reference.size
    end
  end
 =20
  attr_reader :reference
  def initialize
    @reference =3D Array.new(self.class.refsize)
  end
end

class Foo < Referenceable
  attr_reference :a,:b
end

f =3D Foo.new
f.a =3D 1
f.b =3D 2
f.reference
=3D> [1,2]
f.reference[0] =3D 'test'
f.a
=3D> 'test'

regards,
Ed

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