From: dblack@...
Date: 2005-12-28T10:45:11+09:00
Subject: Re: Is there an easy way to extend an object?

Hi --

On Wed, 28 Dec 2005, Jeff Cohen wrote:

> Given an object, is there a clean way of creating a new object that
> wraps the original and then adds a new method?
>
> It doesn't have to wrap the old object if there's a way to directly add
> a new method to the object (I'm allowed to change the incoming object).
>
> def extend_it(obj)
>
>  # how do I add a method to obj
>  # or create a wrapper for it?

You can directly define a method on a particular object:

   def obj.new_method
     ...
   end

You can also create a module, and then use 'extend' to add that
module's instance method's to the object's capabilities.

   module M
     def x
     end
   end
   obj.extend(M)

There are a few more variants on these if they're not what you
need....


David

-- 
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black