require 'active_support/core_ext/object/blank' class Class def superclass_delegating_reader(*names) class_name_to_stop_searching_on = superclass.name.blank? ? "Object" : superclass.name names.each do |name| class_eval(<<-EOS, __FILE__, __LINE__ + 1) def self.#{name} # def self.only_reader if defined?(@#{name}) # if defined?(@only_reader) @#{name} # @only_reader elsif superclass < #{class_name_to_stop_searching_on} && # elsif superclass < Object && superclass.respond_to?(:#{name}) # superclass.respond_to?(:only_reader) superclass.#{name} # superclass.only_reader end # end end # end def #{name} # def only_reader self.class.#{name} # self.class.only_reader end # end def self.#{name}? # def self.only_reader? !!#{name} # !!only_reader end # end def #{name}? # def only_reader? !!#{name} # !!only_reader end # end EOS end end def superclass_delegating_writer(*names, &block) names.each do |name| class_eval(<<-EOS, __FILE__, __LINE__ + 1) def self.#{name}=(value) # def self.property=(value) @#{name} = value # @property = value end # end EOS self.send("#{name}=", yield) if block_given? end end # These class attributes behave something like the class # inheritable accessors. But instead of copying the hash over at # the time the subclass is first defined, the accessors simply # delegate to their superclass unless they have been given a # specific value. This stops the strange situation where values # set after class definition don't get applied to subclasses. def superclass_delegating_accessor(*names, &block) superclass_delegating_reader(*names) superclass_delegating_writer(*names, &block) end end