From: Nikodemus Siivola <tsiivola@...>
Date: 2002-08-07T18:52:42+09:00
Subject: Re: Dup and Clone


On Wed, 7 Aug 2002, Tom Gilbert wrote:

> a = Marshal.restore(Marshal.dump(b))

a) It's ugly.
b) Not everything can be marhalled anyway.

IMHO, the right thing to do is to redefine clone for those classes that
need special treatment. The object should know how to clone it self.

Of course, something like the following would be nice the base distro.
Notice how it just redefines clone, and also uses clone to copy it's
instance variable as well -- so to be a true deep copy the instance
variables have to include the DeepClone as well.

Untested -- written from memory:

module DeepClone
   alias clone shallow_clone
   def clone
      klone = self.shallow_clone
      self.instance_variables.each { |var|
         val = self.var.clone
         klone.__send__("#{var}=",val)
      }
      return klone
  end
end

  -- Nikodemus
------------------------------------------------------------
 I refuse to have a battle of wits with an unarmed person.