vendor/rails/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb

   1 # Extends the class object with class and instance accessors for class attributes,
   2 # just like the native attr* accessors for instance attributes.
   3 #
   4 #  class Person
   5 #    cattr_accessor :hair_colors
   6 #  end
   7 #
   8 #  Person.hair_colors = [:brown, :black, :blonde, :red]
   9 class Class
  10   def cattr_reader(*syms)
  11     syms.flatten.each do |sym|
  12       next if sym.is_a?(Hash)
  13       class_eval(<<-EOS, __FILE__, __LINE__)
  14         unless defined? @@#{sym}  # unless defined? @@hair_colors
  15           @@#{sym} = nil          #   @@hair_colors = nil
  16         end                       # end
  17                                   #
  18         def self.#{sym}           # def self.hair_colors
  19           @@#{sym}                #   @@hair_colors
  20         end                       # end
  21                                   #
  22         def #{sym}                # def hair_colors
  23           @@#{sym}                #   @@hair_colors
  24         end                       # end
  25       EOS
  26     end
  27   end
  28
  29   def cattr_writer(*syms)
  30     options = syms.extract_options!
  31     syms.flatten.each do |sym|
  32       class_eval(<<-EOS, __FILE__, __LINE__)
  33         unless defined? @@#{sym}                       # unless defined? @@hair_colors
  34           @@#{sym} = nil                               #   @@hair_colors = nil
  35         end                                            # end
  36                                                        #
  37         def self.#{sym}=(obj)                          # def self.hair_colors=(obj)
  38           @@#{sym} = obj                               #   @@hair_colors = obj
  39         end                                            # end
  40                                                        #
  41         #{"                                            #
  42         def #{sym}=(obj)                               # def hair_colors=(obj)
  43           @@#{sym} = obj                               #   @@hair_colors = obj
  44         end                                            # end
  45         " unless options[:instance_writer] == false }  # # instance writer above is generated unless options[:instance_writer] == false
  46       EOS
  47     end
  48   end
  49
  50   def cattr_accessor(*syms)
  51     cattr_reader(*syms)
  52     cattr_writer(*syms)
  53   end
  54 end