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}
  15           @@#{sym} = nil
  16         end
  17
  18         def self.#{sym}
  19           @@#{sym}
  20         end
  21
  22         def #{sym}
  23           @@#{sym}
  24         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}
  34           @@#{sym} = nil
  35         end
  36
  37         def self.#{sym}=(obj)
  38           @@#{sym} = obj
  39         end
  40
  41         #{"
  42         def #{sym}=(obj)
  43           @@#{sym} = obj
  44         end
  45         " 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