From: dblack@...
Date: 2006-09-25T07:21:05+09:00
Subject: Re: How do I create an attribute accessor to do this...

Hi --

On Mon, 25 Sep 2006, J2M wrote:

> I want to be able to do this to merge a hash into attribute bas on
> instance bar in class foo;
>
> bar = Foo.new
> bar.bas << { :this => "that" }
>
> Is there any way to define the accessor in Foo to be able to do this?

Here's one way.  It involves assigning a hash to @bar, and adding the
<< behavior to that hash (using a module).

   require 'test/unit'

   class Foo

     attr_reader :bas

     module UpdateAppender
       def <<(other)
         update(other)
       end
     end

     def initialize
       @bas = {}.extend(UpdateAppender)
     end

   end


   class TestMerging < Test::Unit::TestCase
     def test_1
       f = Foo.new
       f.bas << { :this => "that" }
       assert_equal(f.bas.keys, [:this])
     end
   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