From: Robert Klemme <bob.news@...>
Date: 2004-05-18T16:58:50+09:00
Subject: Re: Why do #dup and #clone behave differently with respect to instance methods


"Florian Gross" <flgr@ccan.de> schrieb im Newsbeitrag
news:2gsdj3F5va1pU1@uni-berlin.de...
> Robert Klemme wrote:
>
> > "While clone is used to duplicate an object, including its internal
state,
> > dup typically uses the class of the descendent object to create the
new
> > instance."
> > http://www.ruby-doc.org/docs/rdoc/1.9/classes/Object.html#M000889
> > I'm interested in the reasoning behind this.
>
> I think the rationale is singleton methods being part of internal state.
> I'm actually depending on this behavior for stripping singleton methods
> from potentially dangerous objects so if this is to be changed I would
> need an alternative way to clone objects without their singleton
methods.

Sounds reasonable.  Still *something* strikes me as odd: #class still
returns the original class.  Why doesn't it return the singleton class?

>> class Foo;end
=> nil
>> f=Foo.new
=> #<Foo:0x10189578>
>> f.class
=> Foo
>> f.class.id
=> 135026484
>> def f.bar; "bar";end
=> nil
>> f.bar
=> "bar"
>> f.class
=> Foo
>> f.class.id
=> 135026484
   ^^^^^^^^^
One *could* expect something different here.  Any comments?

Regards

    robert