segundo ejercicio del taller de metaprogramacón

two.rb

module Atribulator
  module ClassMethods
    def my_attr_reader(name)
      define_method("#{name}") do
        instance_variable_get("@#{name}")
      end
    end

    def my_attr_writer(name, my_type = nil)
      if my_type.nil?
        define_method("#{name}=") do |value|
          instance_variable_set("@#{name}", value)
        end
      else
        define_method("#{name}=") do |value|
          raise ArgumentError unless value.is_a?(my_type)
          instance_variable_set("@#{name}", value)
        end
      end
    end

    def my_attr_accessor(name, forced_type = nil)
      my_attr_reader(name)
      my_attr_writer(name, forced_type)
    end
  end

  def self.included(klass)
    klass.extend ClassMethods
  end
end

class Two
  include Atribulator
  my_attr_accessor :foo, String
end

two = Two.new

two.foo = "bar"

puts "two.foo => #{two.foo}"
begin
  two.foo = 2
rescue
  puts "cazado!"
end