From: Markus Fischer <markus@...>
Date: 2009-05-26T19:20:11+09:00
Subject: Re: String representing relative file name, adding (meta) data?

Hi,

many things, I surely learned a *lot* from your post!

The downside is that "Set" failed me (or I failed, POV :). I always lost 
my "added" information (I tested with simple instance_eval) until I 
figured out the following:

- Set uses Hash internall
- Hash.store says the following about Strings:
"a String passed as a key will be duplicated and frozen"

I don't know how to verify 100%, but it seems that's way I'm "loosing" 
my data:

$ cat meta.rb
require 'pp'
require 'set'

set = Set.new
set.add('foo')
s = 'bar'
s.instance_eval { @src = 'source' }
set.add(s)

set.each { |e|
     pp e.instance_eval { @src }
}

$ ruby meta.rb
nil
nil

The second 'nil' should have been "source".

Seems I need to go for non-String object in my case :(

- Markus