How to include Ruby class extensions from other modules?

Question

I want to make class extensions available to other modules/classes/files. For example:

module UsefulStuff
  class Object
    def blank?
      respond_to?(:empty?) ? empty? : !self
    end
  end
end

in other class/module/file:

if string.blank? ...

What and how do I include/load/require/... to make this work?

In the case of blank?, yes, it should work for all classes that have an empty? method (String, Array, Hash). However, more generally, my question is, when I extend a Class how do I include it in other files so that objects in those other files will see the extension? Could you provide an example where the class extension is in one file, and the use of it is in another file (which might be a module, a class, or just a script with main code). — davidg
– davidg, Commented Sep 1, 2012 at 13:21

Nat Ritmeyer · Accepted Answer · 2012-09-27 07:57:22Z

4

You should use a module instead of a class:

module UsefulStuff
  module Blank
    def blank?
      respond_to?(:empty?) ? empty? : !self
    end
  end
end

and you can include it in String class:

class String
  include UsefulStuff::Blank
end

or if you want it to be global for objects:

class Object
  include UsefulStuff::Blank
end

Nat Ritmeyer

5,6868 gold badges49 silver badges60 bronze badges

answered Sep 1, 2012 at 8:33

Nucc

1,0318 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1