[Cuis] Copy vs Clone

[Juan Vuletich]

Hi Hannes,

I just did a few clarifications, that you might want to include in the 
summary.

Thanks,
Juan Vuletich

On 5/15/2015 8:08 AM, H. Hirzel wrote:
> I have summarized this thread so far under issue 55
>
> https://github.com/Cuis-Smalltalk/Cuis-Smalltalk-Dev/issues/55
>
> NotesOnMorphic.md -- add note about #copy
>
> Morphs should be copied using #copy.
>   #clone should be deprecated.
>
> Is this still the conclusion?
>
> --Hannes
>
> On 5/15/15, Ken.Dickey<Ken.Dickey at whidbey.com>  wrote:
>> I seem to recall an early Smalltalk paper (OOPSLA?) on "Creation Relations"
>> which specifically manage share vs duplicate copy semantics.
>>
>> I am most familiar with this from prototype based multimedia authoring
>> environments.
>>
>> In brief, there are cases where one wants to distinguish where ivar state is
>> shared vs individual.
>>
>> So I make a new, say automobile.  It gets its own (unshared) tires, doors,
>> and engine but all cars manufactured by Honda share their manufacturer.
>>
>> I believe this is the reason for Object's definition of #copy, which allows
>> complete control of share/duplicate:
>>
>> Object>>copy
>> 	^self shallowCopy postCopy
>>
>> I am not proposing a system which manages "creation relations" here, just
>> pointing out the need for awareness of the Share vs Duplicate aspect of
>> Copy/Clone semantics.
>>
>> Since I am working on adding drag-n-drop behaviors to individual morphs, my
>> usages are more prototype like.  More Self-like.
>>
>> Morph's #copy has very different semantics which basically disallows
>> sharing:
>>
>> Morph>>copy
>> 	^ Object unStream: (ReferenceStream streamedRepresentationOf: self)
>>
>> Hence some of my inital confusion with #copy.  Same name, different
>> semantics.
>>
>> --
>> -KenD
>>
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