MrProper

MrProper provides a method for NilClass that avoids raising errors when calling blocks upon it.

It defines the function is_defined, which returns self for Enumerable and [] for NilClass.

Came up with this idea when developing Teambox, an open source project management and collaboration tool available at http://www.teambox.com

Example

The following code would raise an exception, because nil.each does not exist:

params[:suscribers] = nil
params[:suscribers].each do |suscriber|
Emailer.deliver_notification suscriber
end

So you would normally need to do the following to avoid it:

params[:suscribers] = nil
if params[:suscribers]
params[:suscribers].each do |suscriber|
Emailer.deliver_notification suscriber
end
end

By using is_defined, the previous code would look like this:

params[:suscribers] = nil
params[:suscribers].is_defined.each do |suscriber|
Emailer.deliver_notification suscriber
end

Installation

Just copy mrproper.rb into config/initializers/mrproper.rb (Ruby on Rails) or any other place where it will get loaded by your app.

Copyright © 2009 Pablo Villalba, released under the MIT license