class Module # Declare an attribute accessor with an initial default return value. # # To give attribute :age the initial value 25: # # class Person # attr_accessor_with_default :age, 25 # end # # some_person.age # => 25 # some_person.age = 26 # some_person.age # => 26 # # To give attribute :element_name a dynamic default value, evaluated # in scope of self: # # attr_accessor_with_default(:element_name) { name.underscore } # def attr_accessor_with_default(sym, default = nil, &block) raise 'Default value or block required' unless !default.nil? || block define_method(sym, block_given? ? block : Proc.new { default }) module_eval(<<-EVAL, __FILE__, __LINE__) def #{sym}=(value) # def age=(value) class << self; attr_reader :#{sym} end # class << self; attr_reader :age end @#{sym} = value # @age = value end # end EVAL end end