Nigilist is extremely useful for implement Null Object pattern. It allows null object to return
false for all question-methods,
nil for all non-bang-methods,
 for all methods in plural form (and in Ruby on Rails null-relation for same name ActiveRecord model) without defining them.
gem install nigilist
class Order < ActiveRecord::Base end class Guest include Nigilist def polite? true end def locale 'ru' end end current_user = Guest.new current_user.admin? # false — for all question methods current_user.polite? # true — becase it is explicit defined current_user.orders # Order.none — for all plural methods because same singular name ActiveRecord model exists current_user.planets #  — for all plural methods without because singular name ActiveRecord model doesn't exists current_user.address # nil — for all non question, non plural and non bang methods current_user.locale # 'ru' — becase it is explicit defined
Explanation of Null Object pattern
For example, you have a
User model, with
#admin? method, and
Guest model allows you use same interface for both authorized and unauthorized users like so:
class Guest def admin? false end end current_user = current_session.user || Guest.new current_user.admin?
So when your project grows and other methods got it place inside
User model you have to define same methods in
Guest model which contains no logic but only return
nil. In that case Nigilist could be helpful.
Nigilist is free software, and may be redistributed under the MIT License.
The gem about one method
The gem contains exactly one module with one method defined:
method_missing. I'm sure you able to implement it by yourself in couple of minutes. So feel free just to copy it from