From: James Edward Gray II <james@...>
Date: 2010-11-03T05:05:56+09:00
Subject: Re: the dark side of inherited methods

On Nov 2, 2010, at 12:02 PM, Josh Cheek wrote:

> On Tue, Nov 2, 2010 at 11:19 AM, James Edward Gray II <james@graysoftinc.com
>> wrote:
> 
>> Of course, inheritance has it's place and uses but I feel it's definitely
>> overused.
>> 
> 
> Can you give some examples of where it has its place?

I have to lay down the law, because there will always be exceptions, but I thought Robert Klemme describes it pretty good a few messages back with the "is a" check.

> I realized the only time I ever subclass anything
> is ActiveRecord::Base (and I'm not really sure what that offers over
> modules, DataMapper uses modules, for example).

ActiveRecord is an interesting case of Rubyish inheritance too.  It's really a focused DSL, I think.  You inherit from ActiveRecord::Base to get a bunch of macros (has_many(), validates_presence_of(), etc.).  Using this mini-DSL you describe your model and that changes how the objects produced from that class will behave.  It's a build-your-on-class-with-shortcuts system, I think.

James Edward Gray II