From: Alex Gutteridge <alexg@...>
Date: 2007-08-27T14:32:55+09:00
Subject: Re: Override object initialization, add a filepath attribute.

On 27 Aug 2007, at 13:45, Aaron Smith wrote:

> Is it possible to override initializations so that anytime an  
> object is
> created there is a "filepath" attribute put on it?
>
> maybe?
>
> class Object
>  def initialize
>   super
>   class << self
>     attr_accessor :filepath
>   end
>   self.filepath = $0
>  end
> end
>
> See what i'm going for? Any ideas on how to get away with this?

Do you want the name of the file each object is defined in? I think  
you want __FILE__ instead of $0 in that case since $0 is always the  
top level Ruby program.

Also there is no superclass for Object so super#initialize won't work  
I think. This maybe gets closer - but still doesn't actually work:

[alexg@powerbook]/Users/alexg/Desktop(55): cat main.rb
require 'foo'
require 'filepath'

f = Foo.new
p f.filepath
[alexg@powerbook]/Users/alexg/Desktop(56): cat foo.rb
class Foo
end
[alexg@powerbook]/Users/alexg/Desktop(57): cat filepath.rb
class Object
   attr_accessor :filepath
end

class Class
   alias :old_new :new
   def new(*args)
     result = old_new(*args)
     result.filepath = __FILE__
     result
   end
end
[alexg@powerbook]/Users/alexg/Desktop(58): ruby main.rb
"./filepath.rb"

We would of course like it to output 'foo.rb' if I understand you right.

Alex Gutteridge

Bioinformatics Center
Kyoto University