class LoggerClass
  def self.attr_logger(attribute_name)
    iv_name = "@#{attribute_name}"
    define_method(attribute_name) do
      instance_variable_get(iv_name)
    end
    define_method("#{attribute_name}=") do |value|
      STDERR.puts "setting #{attribute_name} to #{value}"
      instance_variable_set(iv_name, value)
    end
  end
end

class Person < LoggerClass
  attr_logger :age
  attr_logger :name
end

chad = Person.new
chad.age = 321
puts chad.age
puts chad.name