A simple question: How to copy the instance variables of an object to another - already existing - object

Rudi Bichler chaoshierophant at yahoo.com
Sun Jul 31 21:06:53 UTC 2005


 
Cool. That's I was looking for!
Thanks a lot
Rudi
 
 


Bert Freudenberg <bert at impara.de> wrote:
Am 31.07.2005 um 21:35 schrieb Rudi Bichler:

> Hi,
>
> I need some kind of copyTo: functionality, which copies a complete 
> object (i.e. all instance variables) to another object. I need this 
> to "convert" an object of class A into an object of a subclass of 
> A. Something like:
>
> Object subclass: #MyClass
> instanceVariableNames: 'var1 var2' ...
>
> MyClass subclass: #MySubcl
> instanceVariableNames: 'var3' ...
>
> MySubcl class >> newCopyFrom: original
> "create an object of class MySubcl with is - as MyClass - identical 
> to original"
>
> An example of such a functionality is FormCanvas asBalloonCanvas. 
> This method is implemented by creating a BalloonCanvas and 
> initializing it "by hand". I am looking for a generic way - 
> something like copy in Object. Any idea?

Looking into the #copy method in Object you'll notice it calls 
#shallowCopy, which implements a generic copy of all instance 
variables - take a look!

- Bert -




		
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