From: Joel VanderWerf <vjoel@...>
Date: 2005-04-29T03:44:09+09:00
Subject: Re: Deep copy?

Andrew Walrond wrote:
> Is there a deep copy function that I've missed somehow? (dup and clone are 
> both shallow copy functions).
> 
> E.g. How can I make a deep copy of a Hash?
> 
> Ie if
>  a=['who'=>'me'],
> I want
>  b = a.deepcopy
> Such that
>  b['who'].replace('you')
> doesn't result in
>  a == ['who'=>'you']
> 
> I could do 
>  b=YAML::load(YAML::dump(a)
> but it reeks of _wrongness_ ;)

Marshal is a little less wrong than YAML, and it is AFAIK the most 
reliable and general deep copy in ruby.

There was at one time some talk of general-purpose object traversal:

http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/64146