Subclass module + use module_eval to define methods

module.rb

class AttributeAccessor < Module
  def initialize(name)
    @name = name
    module_eval { define_accessors }
  end

private

  def define_accessors
    ivar = "@#{@name}"
    define_writer(ivar)
    define_reader(ivar)
  end

  def define_writer(ivar)
    define_method("#{@name}=") do |value|
      instance_variable_set("#{ivar}", value)
    end
  end

  def define_reader(ivar)
    define_method(@name) do
      instance_variable_get("#{ivar}")
    end
  end
end

module SingletonBook
  extend AttributeAccessor.new(:title)

  def self.title
    "#{super} + super works on singletons!"
  end
end

SingletonBook.title = "Module Subclassing Guide"
puts SingletonBook.title