From: Anders Borch <spam@...>
Date: 2003-04-27T23:14:42+09:00
Subject: Re: How to undefine a member variable ? (or at least hide it from YAML)

Simon Vandemoortele wrote:
> I came across the following problem while using YAML:
> 
> #+v
> require "yaml"
> 
> class A
>   attr_writer :s 
> end
> 
> a = A.new
> 
> puts (a.s ="something").to_yaml 
> => "--- !ruby/object:A \na: something"
> 
> puts (a.s = nil).to_yaml
> "--- !ruby/object:A \na: 
> #-v
> 
> My problem, as you can see, is that:
> 1)  once I've assigned to a member variable there is (to my knowledge) no
>     way to 'undefine' it
> 2)  YAML dumps all defined variables 
> 
> This means that, over time, my object dumps will become more and more
> cluttered with empty entries.  I am sure YAML experts have run into that
> problem and have a lot to say about it ... 
> 
> As I see it: either I find a way to 'undefine' a variable, or I find a way
> to tell YAML *not* to dump nil values. (I prefer the latter of course.)
> 
> 
> Simon
> 

If you have a lot of values that come and go, then why not put them in a 
hash? that should make sure you do not clutter your namespace...

/Anders