From: Damjan Rems <lists@...>
Date: 2012-09-19T15:00:30+09:00
Subject: Re: Bug or feature

Robert Klemme wrote in post #1076534:
> On Tue, Sep 18, 2012 at 8:44 PM, Damjan Rems <lists@ruby-forum.com>
> wrote:
>> Robert Klemme wrote in post #1076432:
>>
>>> For full object tree copy you can do
>>>
>>> irb(main):007:0> c = Marshal.load(Marshal.dump(a))
>>
>> Why is real cloning not implemented in ruby, since this fake cloning can
>> lead to a lot of troubles.
>
> What do you mean - "real cloning"?  Shallow copy is as real as deep
> copy.  They are just different concepts.  If you think about it for a
> moment a deep copy is significantly more difficult to realize
> (especially with object graphs which have different paths to the same
> instance).  It is totally reasonable to provide a shallow copy as
> default - btw. Java does it, too.
>
> And you can simply create your deep copy method:
>
> class Object
>   def clone_deep
>     Marshal.load(Marshal.dump(self))
>   end
> end
>
> Kind regards
>
> robert

So there is a good reason not to implement object duplication (deep 
cloning). Results may be unpredictable so better don't do it.

Although I never liked the argument if it is good for them than it is 
good for us.

by
TheR

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