From: Csaba Henk <csaba@..._for_avoiding_spam.org>
Date: 2005-01-26T23:30:48+09:00
Subject: Re: clone and dup

On 2005-01-26, Robert Klemme <bob.news@gmx.net> wrote:
>
> "Keith P. Boruff" <kboruff@optonline.net> schrieb im Newsbeitrag
> news:89KJd.989$HR6.889@fe10.lga...
>> After reading about these two methods for the Object class in "Pragmatic
>> Programmer", I'm still having a hard time understanding the differences.
>> Can someone point me to some better info on these or explain it (I do
>> understand the differences between deep and shallow copying).
>
> They do both shallow copy.
>
> Here's a difference:
>
>>> s="foo".freeze
>=> "foo"
>>> s.frozen?
>=> true
>>> s.clone.frozen?
>=> true
>>> s.dup.frozen?
>=> false

Or: 

irb(main):189:0> o=Object.new
=> #<Object:0x414c1f54>
irb(main):190:0> def o.foo; end
=> nil
irb(main):191:0> o2=o.clone
=> #<Object:0x414be1b0>
irb(main):192:0> o2.foo
=> nil
irb(main):193:0> o3=o.dup  
=> #<Object:0x414baee8>
irb(main):194:0> o3.foo
NameError: undefined method `foo' for #<Object:0x414baee8>
        from (irb):194
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:67

Csaba