From: Timothy Hunter <cyclists@...>
Date: 2006-02-13T06:38:25+09:00
Subject: Re: Equivalent of const modifier

eastcoastcoder@gmail.com wrote:
> Very often, I'd like to ensure (and document) that a method will not
> change any of its parameters:
> 
> # This looks at, but doesn't modify, a and b
> def mymethod(a, b)
> end
> 
> In C++ I can do this with the const modifier.
> 
> Is there anyway to do this in Ruby?
> 
> I'd call freeze, except that would freeze the original a as well.
> I'd call dup/clone and then freeze, but those aren't deep copies, from
> what I understand.
> 
> So, I guess my question boils down to:
> Is there a way to make a frozen, full (ie deep) copy of an object?
> 

You can make a deep copy and then freeze the copy.
http://www.rubygarden.org/ruby?Make_A_Deep_Copy_Of_An_Object