Macro for adding an `initialize` function and creating `attr_reader`s for each variable passed.

object.rb

class Object
  def self.init(*names)
    define_method(:initialize) do |*args|
      names.zip(args).each do |name, arg|
        instance_variable_set("@#{name}", arg)
      end

      singleton_class.class_eval do
        attr_reader *names
      end
    end
  end
end

class Test
  init :foo
end

p Test.new(:bar).foo == :bar