Running a method after the initialize method

Question

I would like to write some ruby code that runs after the initialize method is called. This code can be in a class or a module. How would I write this?

Here is an example of what I want:

class Base
  def after_init
    puts "after init"
  end

class A < Base # Option 1, use a class
end

class B < Base
  def initialize
    puts "in init"
  end
end

module MyMod
  def after_init
    puts "after init"
  end
end

class C
  include Module
end

$> A.new
=> "after init"
$> B.new
=> "in init"
=> "after init"
$> C.new
=> "after init"

What I definitely don't want to do is make an explicit call to super. Is there a way to do this? I don't care if it uses a lot of Ruby's reflective abilities. Thanks!

Answer 1

class Base
  def after_init
    puts "Base#after_init"
  end

  def self.inherited(klass)
    class << klass
      alias_method :__new, :new
      def new(*args)
        e = __new(*args)
        e.after_init
        e
      end
    end
  end
end

module MyMod
  def after_init
    puts "MyMod#after_init"
  end
  def self.included(klass)
    class << klass
      alias_method :__new, :new
      def new(*args)
        e = __new(*args)
        e.after_init
        e
      end
    end
  end
end

class A < Base
end

class B < Base
  def initialize
    puts "B#initialize"
  end
end

class C
  include MyMod
  def initialize
    puts "C#initialize"
  end
end

A.new
B.new
C.new