From: Brian Candler <b.candler@...>
Date: 2008-10-29T21:26:14+09:00
Subject: Re: inherited behaviour.

Macario Ortega wrote:
> Hi, I have this situation where it would save me some typing if the 
> inherited callback was called after the class was fully defined (with 
> all its methods).

But it's never "fully defined", as it can be extended at any time in the 
future. (Or depending on how you look at it, it's "fully defined" at the 
instant the subclass is created, before any methods are added to it)

> is there a way I can get "yeah!" instead of "damn!"?

class Class
  alias :old_new :new
  def new(parent = Object, &blk)
    child = old_new(parent, &blk)
    parent.delayed_inherited(child) if 
parent.respond_to?(:delayed_inherited)
    child
  end
end

class A
  def self.delayed_inherited(klass)
    p klass.respond_to?(:my_method) ? "yeah!" : "damn!"
  end
end

B = Class.new(A) do
  def self.my_method
  end
end

p "too late!" if B.respond_to?(:my_method)

### Or you could just trigger it explicitly:

class Class
  def ok
    return unless superclass.respond_to?(:delayed_inherited)
    superclass.delayed_inherited(self)
  end
end

class A
  def self.delayed_inherited(klass)
    p klass.respond_to?(:my_method) ? "yeah!" : "damn!"
  end
end

class B < A
  def self.my_method
  end
  ok
end

p "too late!" if B.respond_to?(:my_method)

### That's only two characters to type for each class definition :-)
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