From: Eero Saynatkari <ruby-forum-reg@...>
Date: 2006-01-21T03:57:57+09:00
Subject: Re: Class variables in an inheritance hierarchy

Todd Breiholz wrote:
> Assume the following structure:
> 
> class Base
> end
> 
> class Account < Base
> end
> 
> class Opportunity < Base
> end
> 
> 
> I want to have a class variable Account.fields that is different than
> Opportunity.fields, so that all instances of Account can reference the
> Account.fields and all instances if Opportunity can reference
> Opportunity.fields and get the correct results.
> 
> As a reference, I am trying to create something akin to ActiveRecord 
> (for a
> different type of datasource) where each distinct object has it's own 
> set of
> attributes. I've been looking at the ActiveRecord code, but being new to
> Ruby it's giving me a bit of a headache :)

You can use class instance variables (Classes Are Objects Too(tm) :)

  class Account < Base
    # We are in the context of the class so this variable
    # will belong to the class, not its instances.
    @fields = something
  end

You would also need to set up accessors for the variables.

> Thanks!
> 
> Todd Breiholz


E


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