From: Jason Roelofs <jameskilton@...>
Date: 2008-04-15T03:02:48+09:00
Subject: Re: Mutable member variables -- surprising behavior

On Mon, Apr 14, 2008 at 1:43 PM, ara.t.howard <ara.t.howard@gmail.com> wrote:
>
>  On Apr 14, 2008, at 11:34 AM, Jason Roelofs wrote:
>
> >
> > # Always give a copy of the array, that way the internal @elems
> > # array is never changed.
> > def elems
> >  @elems.clone
> > end
> > end
> >
>
>  does not work, neither does dup.  both are rather shallow in ruby.  if you
> *really* want a copy you need
>
>   Marshal.load(Marshal.dump(@elems))
>
>  otherwise you'll end up with subtle bugs when the array is cloned, but
> elements inside of it, or deeper, are not.
>
>  fyi.
>
>  a @ http://codeforpeople.com/
>  --
>  we can deny everything, except that we have the possibility of being
> better. simply reflect on that.
>  h.h. the 14th dalai lama
>


Eep, yeah, I forgot about that. #dup and #clone won't work, sorry for
that misinformation.

Jason