[Cuis] Copy vs Clone

[Juan Vuletich]

Good!

Cheers,
Juan Vuletich

On 5/14/2015 9:23 PM, David T. Lewis wrote:
> Forwarding to squeak-dev for consideration after the next release.
>
> Object>>clone can be replaced by #shallowCopy. Perhaps it is time to
> deprecate #clone.
>
> Juan is removing it from Cuis, with reference to this summary by Levente:
> http://lists.gforge.inria.fr/pipermail/pharo-project/2010-January/019801.html
>
> Dave
>
> On Thu, May 14, 2015 at 10:53:12AM -0300, Juan Vuletich wrote:
>> On 5/14/2015 12:22 AM, David T. Lewis wrote:
>>> On Wed, May 13, 2015 at 11:24:09PM -0300, Juan Vuletich wrote:
>>>> Does anybody know why #clone was added to Squeak?
>>>>
>>> I do not know the historical background, but Object>>clone invokes #primitiveClone
>>> in the VM. This is an efficient shallow copy, in which the object header and data
>>> fields are copied to a newly allocated object, and the object hash and GC bits
>>> are updated in the new copy.
>>>
>>> I think that this must have been done for efficiency, to provide the fastest
>>> possible means of shallow copying an object. The methods in the VM and in Object
>>> are both old enough that they had no author initials, so this was a very early
>>> optimization in Squeak.
>>>
>>> Dave
>> Thanks Dave.
>>
>> I searched a bit more and found
>> http://lists.squeakfoundation.org/pipermail/vm-dev/2014-February/014683.html
>> and the more detailed
>> http://lists.gforge.inria.fr/pipermail/pharo-project/2010-January/019801.html
>> (by Levente).
>>
>> After these references, I decided to remove #clone from Cuis. Most
>> senders were replaced by sends to #shallowCopy (it uses the same VM
>> primitive). But for several, calling #copy works the same, and #copy
>> sounds more natural to me. I also refactored several implementations of
>> #copy et al, in SequenceableCollection and AbstractSound hierarchies.
>> Will commit to github soon.
>>
>> Cheers,
>> Juan Vuletich