NullObject addition (http://devblog.avdi.org/2011/05/30/null-objects-and-falsiness/)

null_object.rb

class NullObject < BasicObject
  def initialize(represents = nil)
    @represents = represents || 'NullObject'
  end

  def nil?; true; end
  def present?; false; end
  def blank?; true; end
  def empty?; true; end
  def !; true; end

  def to_a; []; end
  def to_s; ''; end
  def to_f; 0.0; end
  def to_i; 0; end
  def to_str; to_s; end

  def inspect
    "<#{represents}>"
  end

  def method_missing(*args, &block)
    self
  end

  private

  attr_reader :represents
end

date = nil || NullObject.new('NullDate')
date.inspect # => '<NullDate>'