From: Drew Olson <olsonas@...>
Date: 2007-10-26T07:45:26+09:00
Subject: Re: Need help understanding metaclassing

Chris Czub wrote:
> Any ideas?

Basically the same idea as why's solution to dwenthy's array:

class User
  def self.metaclass
    class << self; self; end
  end

  def self.attribs *args
    return @attribs if args.empty?
    attr_accessor *args
    args.each do |arg|
      metaclass.instance_eval do
        define_method(arg) do |val|
          @attribs ||= {}
          @attribs[arg] = val
        end
      end
    end

    class_eval do
      define_method(:initialize) do
        self.class.attribs.each do |attrib,val|
          instance_variable_set("@#{attrib}",val)
        end
      end
    end
  end
end

class UKUser < User
  attribs :name, :age, :weight
  name "john doe"
  age 25
  weight 170
end

u = UKUser.new
puts u.name
puts u.weight
puts u.not_real
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