vendor/rails/activesupport/lib/active_support/core_ext/object/metaclass.rb

   1 class Object
   2   # Get object's meta (ghost, eigenclass, singleton) class
   3   def metaclass
   4     class << self
   5       self
   6     end
   7   end
   8
   9   # If class_eval is called on an object, add those methods to its metaclass
  10   def class_eval(*args, &block)
  11     metaclass.class_eval(*args, &block)
  12   end
  13 end