From: Sean O'Halpin <sean.ohalpin@...>
Date: 2005-11-23T17:27:25+09:00
Subject: Re: pattern: auto-running module init code

Hi Phil,

You can also use super:

class Bar
  def initialize(*args, &block)
    puts "in Bar"
    super
  end
end

class Foo < Bar
  def initialize(*args, &block)
    puts "in Foo"
    super
  end
end

f = Foo.new

module Mod
  def initialize(*args, &block)
    puts "in Mod"
    super
  end
end

class Foo
  include Mod
end

f = Foo.new

--- OUTPUT ---
in Foo
in Bar
in Foo
in Mod
in Bar

or Module.included

class Bar
  def initialize(*args, &block)
    puts "in Bar"
    super
  end
end

class Foo < Bar
  def initialize(*args, &block)
    puts "in Foo"
    super
  end
end

module Mod
  def self.included(obj)
    puts "in Mod"
  end
end

class Foo
  include Mod
end

f = Foo.new

--- OUTPUT ---
in Mod
in Foo
in Bar

but note the different order of initialization.

With extend, you get to choose whether you extend ~before~ the super or ~after~.

So you can have either extend before super = Foo, Mod, Bar (same as
include + super) or extend after super = Foo, Bar, Mod.

Whether this is a pro or a con is up to you to decide.

My own preference in this case is to use include + super.

Regards,

Sean