require 'active_support/core_ext/array/extract_options' # Extends the class object with class and instance accessors for class attributes, # just like the native attr* accessors for instance attributes. # # Note that unlike +class_attribute+, if a subclass changes the value then that would # also change the value for parent class. Similarly if parent class changes the value # then that would change the value of subclasses too. # # class Person # cattr_accessor :hair_colors # end # # Person.hair_colors = [:brown, :black, :blonde, :red] # Person.hair_colors # => [:brown, :black, :blonde, :red] # Person.new.hair_colors # => [:brown, :black, :blonde, :red] # # To opt out of the instance writer method, pass :instance_writer => false. # To opt out of the instance reader method, pass :instance_reader => false. # # class Person # cattr_accessor :hair_colors, :instance_writer => false, :instance_reader => false # end # # Person.new.hair_colors = [:brown] # => NoMethodError # Person.new.hair_colors # => NoMethodError class Class def cattr_reader(*syms) options = syms.extract_options! syms.each do |sym| class_eval(<<-EOS, __FILE__, __LINE__ + 1) unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym} @@#{sym} end EOS unless options[:instance_reader] == false class_eval(<<-EOS, __FILE__, __LINE__ + 1) def #{sym} @@#{sym} end EOS end end end def cattr_writer(*syms) options = syms.extract_options! syms.each do |sym| class_eval(<<-EOS, __FILE__, __LINE__ + 1) unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym}=(obj) @@#{sym} = obj end EOS unless options[:instance_writer] == false class_eval(<<-EOS, __FILE__, __LINE__ + 1) def #{sym}=(obj) @@#{sym} = obj end EOS end self.send("#{sym}=", yield) if block_given? end end def cattr_accessor(*syms, &blk) cattr_reader(*syms) cattr_writer(*syms, &blk) end end