From: dblack@...
Date: 2006-10-03T22:07:26+09:00
Subject: Re: Newbie: Question => How to do this with Classes ?

Hi --

On Tue, 3 Oct 2006, Eye Matz wrote:

> class Important
>  def set_this_value_method(value)
>  end
> end
>
> class SemiImportant < Important
>   set_this_value_method :something_or_anything
> end
>
> Could some kind sould please, please take the time to explain the
> fundamentals of Ruby's class/module functionality in regards to the
> above example.

In the second snippet, you're sending the message
"set_this_value_method" to the class object SemiImportant.  In order
for that object to understand the message, a method called
set_this_value_method has to be defined either in

   1. the object's class (which, in this case, is actually Class
   2. on a singleton (per-object) basis for the object
   3. on a singleton basis in the object's super[super[super...]]class.

So, you could do this:

   class Important
     def self.set_this_value_method(value)  # note the 'self'
     end
   end

   class SemiImportant < Important
     set_this_value_method :x
   end


David

-- 
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org