[Cuis-dev] Bag>>#sum:ifEmpty:

[Luciano Notarfrancesco]

Yes, the method assumes the block is a function (it maps one element to
only one value). We talked about this here a couple of times. The
Collection protocol is very “functional”, specially messages like
#collect:, #select:, #detect:, etc, and using them with blocks that are
functions is the most natural way to use them, and I don’t think we loose
anything by making the assumption that the blocks for these messages are
functions.
Moreover, the whole point of Bag is to be able to efficiently store
elements with lots of repetitions, possibly millions of repetitions that
otherwise wouldn’t even fit in memory. If #sum: iterated over all the
repetitions it would defeat the original purpose of Bag. And I argue that
this is not necessary because no one would ever call #sum: with a block
that is not a function, at least I never had the need to do that, and it
feels unnatural to use #sum: in that way and I’d use #do: instead.
If you think this assumption is strange, think about all the other
assumptions that collections make. For example, you cannot change a
collection while you’re iterating it. It would just feel wrong to change a
collection while you iterate it, we don’t need to try to support that
because who would do that?


On Thu, 3 Nov 2022 at 03:12 Hernán Wilkinson <hernan.wilkinson at 10pines.com>
wrote:

> How does that optimization work?
> Because I thought about evaluating the block and multiplying that for the
> number of elements, but that makes sense if the block returns always the
> same value por the same element, if it does not then it will not work...
>
>
> On Wed, Nov 2, 2022 at 3:24 PM Juan Vuletich <juan at cuis.st> wrote:
>
>> On 11/1/2022 11:23 PM, Hernán Wilkinson via Cuis-dev wrote:
>>
>> yeap, the current implementation is not correct.
>> Juan, attached is a change set that fixes it and another with the related
>> tests.
>>
>> Cheers!
>> Hernan.
>>
>> On Tue, Nov 1, 2022 at 3:39 AM Luciano Notarfrancesco <luchiano at gmail.com>
>> wrote:
>>
>>> I’m afk right now so I cannot check, but it sounds like I made a
>>> mistake. Of course it should be the value of aBlock at each element times
>>> the number of occurrences.
>>>
>>> On Tue, 1 Nov 2022 at 07:33 Hernán Wilkinson <
>>> hernan.wilkinson at 10pines.com> wrote:
>>>
>>>> Hi,
>>>>  the implementation of Bag>>#sum: aBlock ifEmpty: emptyBlock does not
>>>> use the parameter aBlock at all and assumes that each of the elements
>>>> answers the message *
>>>>  @Luciano Notarfrancesco <luchiano at gmail.com> the implementation is
>>>> yours and it is very new? Is there a reason you did that way?
>>>>
>>>> Thanks
>>>> Hernan
>>>>
>>>>
>>>> --
>>>>
>>>> *Hernán Wilkinson Agile Software Development, Teaching & Coaching*
>>>> *Phone: +54-011*-4893-2057
>>>> *Twitter: @HernanWilkinson*
>>>> *site: http://www.10Pines.com <http://www.10pines.com/>*
>>>> Address: Alem 896, Floor 6, Buenos Aires, Argentina
>>>>
>>>
>>
>> --
>>
>> *Hernán Wilkinson Agile Software Development, Teaching & Coaching*
>> *Phone: +54-011*-4893-2057
>> *Twitter: @HernanWilkinson*
>> *site: http://www.10Pines.com <http://www.10pines.com/>*
>> Address: Alem 896, Floor 6, Buenos Aires, Argentina
>>
>>
>> Hi Hernán,
>>
>> Your fix disables the optimization Luciano did. I chose to fix Luciano's
>> code. Did the same for #product: (same bug). Integrated your tests, and
>> added another one for #product:
>>
>> Thanks,
>>
>> --
>> Juan Vuletichcuis.stgithub.com/jvuletichresearchgate.net/profile/Juan-Vuletichindependent.academia.edu/JuanVuletichpatents.justia.com/inventor/juan-manuel-vuletichlinkedin.com/in/juan-vuletich-75611b3twitter.com/JuanVuletich
>>
>>
>
> --
>
> *Hernán WilkinsonAgile Software Development, Teaching & Coaching*
> *Phone: +54-011*-4893-2057
> *Twitter: @HernanWilkinson*
> *site: http://www.10Pines.com <http://www.10pines.com/>*
> Address: Alem 896, Floor 6, Buenos Aires, Argentina
>
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