From: "John W. Long" <ng@...>
Date: 2005-05-04T12:45:56+09:00
Subject: [ANN] Defaultable 0.0.3

This is the first public release of a very small project I've been 
working on recently. It's very similar actually to Ara.T.Howard's 
implementation of Traits.

The goal of the project is to provide a mixin for objects that adds a 
series custom attribute methods for default values:

   require 'defaultable'

   class TestObject
     include Defaultable
     default_accessor :test => 'Hello world!'
   end

   o = TestObject.new
   puts o.test #=> 'Hello world!'

If the object's constructor has a hash as the last parameter it assumes 
it's an options hash and automatically extracts values for the object 
from it:

   class TestObject
     def initialize(options = {})
     end
   end

   o = TestObject.new(:test => 'Cool beans!')
   puts o.test #=> 'Cool beans!'

The current implementation also works well with inheritance allowing 
inherited objects to inherit their parent object's attribute defaults.

I'm particularly interested in feedback on the implementation. I'm not a 
metaclass guru, so for those of you who are, I would especially 
appreciate feedback on the class methods "included" and "method_added" 
on the module. These methods are currently hacks to make it useful, but 
their implementation isn't pretty.

Download:
http://johnwlong.com/downloads/iblp-mixins-0.0.3/lib/defaultable.rb

Tests:
http://johnwlong.com/downloads/iblp-mixins-0.0.3/test/unit/defaultable_test.rb

Defaultable is currently part of another small project which can be 
downloaded here:

http://johnwlong.com/downloads/iblp-mixins-0.0.3.tgz

--
John Long
http://wiseheartdesign.com