From: Charles Hixson <charleshixsn@...>
Date: 2000-06-19T17:57:43+00:00
Subject: [ruby-talk:03528] Re: Deep copy?

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GOTO Kentaro wrote:

> ... snip ...
> A serious problem is the meaning of copy.  More precisely, we don't
> have a consensus to what an object is,i.e. the state of an object. For
> example, the behavior of an IO object in the future is undecidable, so
> ... snip ...
> -- gotoken

The smalltalk approach quoted above suggests a method around this.  Implement
a (nearly) vacuous method in Object, and name it DeepCopy (the default for
Object could be the same as the shallow copy).  Then it is the responsibility
of every descendant that wishes DeepCopy to be implemented to do the
implementation.  Of course numeric methods would have a clear and obvious
method of doing a DeepCopy, but as it isn't generally needed, many of the
classes could just leave this to be implemented by a descendant.


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