prepend

So far, we've discussed the include, extend, and module methods and namespaces. There is one more aspect to modules that came with the Ruby 2.0 release several years ago: prepend. prepend is not often used, perhaps because it is not well understood. Let's change that.

First, let's consider the following example:

module ClassLogger
  def log(msg)
    "[#{self.class}] #{msg}"
  end
end
class User
  include ClassLogger
  def log(msg)
    "[#{Time.now.to_f.to_s}] #{super(msg)}"
  end
end
class Company
  prepend ClassLogger
  def log(msg)
    "[#{Time.now.to_f.to_s}] #{super(msg)}"
  end 
end

We've created a module called ClassLogger, which implements a log method. This method wraps a string and outputs the current class. We've also created two classes, Company and User, which...