rails/activesupport/lib/active_support/multibyte.rb

module ActiveSupport #:nodoc:
  module Multibyte
    autoload :Chars, 'active_support/multibyte/chars'
    autoload :Unicode, 'active_support/multibyte/unicode'

    # The proxy class returned when calling mb_chars. You can use this accessor to configure your own proxy
    # class so you can support other encodings. See the ActiveSupport::Multibyte::Chars implementation for
    # an example how to do this.
    #
    #   ActiveSupport::Multibyte.proxy_class = CharsForUTF32
    def self.proxy_class=(klass)
      @proxy_class = klass
    end

    # Returns the current proxy class
    def self.proxy_class
      @proxy_class ||= ActiveSupport::Multibyte::Chars
    end
  end
end