[Cuis-dev] [DEFECT] #copyFrom:count: for OrderedCollections

[Juan Vuletich]

On 2/6/2024 1:37 PM, Nicolas Cellier via Cuis-dev wrote:
> Hi Juan,
>
> Le mar. 6 févr. 2024 à 17:22, Juan Vuletich via Cuis-dev
> <cuis-dev at lists.cuis.st>  a écrit :
>> Let me also elaborate a bit on the rationale.
>>
>> In Smalltalk-80 (and every other Smalltalk system since then), the docs
>> will say that #new: will answer a collection of the requested size. But
>> it is not like that for Set, Dictionary, OrderedCollection and a few
>> others, that give a completely different semantics to this message. It
>> is no _that_ bad when the message is sent to an explicit class, although
>> you need to be aware of this.
>>
> IMO, better fix the comment than the behavior.
> The purpose of new: has always been to allocate enough room for
> storing n elements.
> For fixed size (Arrayed) collections, the answer is a collection
> initialized with Undefined object(s).
> Or whatever is the default element for non-pointer kind (ByteArray,
> String, ...).
> So it effectively has a size n, but the contents is somehow
> un-initialized, only the container is.
>
> For OrderedCollection, we don't have to initialize any contents at
> all, because that will be so much easier by explicitly adding.
> And for Set and Dictionary, we would have to initialize the contents
> with n different arbitrary objects, which would be absolutely
> nonsensical.
>
> So, IMO, the expectation (SomeCollectionClass new: n) size = n is
> plain wrong, that's not the intent of new:.
> It's just true for fixed size collections, because, well, they have a
> fixed size...
>
> Of course, you can change that, but now you'll need another message to
> express the intention to allocate enough room for n elements.
> And if you do that, you'll just re-invent new: with another name.
> I don't understand why you would do that, except for creating
> cross-dialect nightmares.
>

Nope. Added #newWithRoomForMoreThan: and this solves the false polymorphism.

> Nicolas

Thanks,

-- 
Juan Vuletich
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