[Cuis-dev] [Integrated] Re: Fix for SequentiableCollection>>combinations:atATimeDo:

[Andres Valloud]

I'd rather have the system not create an enormous amount of garbage 
should anyone try something like this:

	1 to: 30 :: combinations: 15 atATimeDo: [:x | x doSomething]

If copies were being made, I'd expect the allocation / GC work to vie 
for execution time domination.

On 5/25/19 06:05, Hernan Wilkinson via Cuis-dev wrote:
> Hi Luciano,
>   thank you for the fix. It is integrated now and I added a couple of 
> tests to SequenceableCollectionTest, one when k is cero and another for 
> the normal case.
> 
>   When I wrote the test for the normal case I notice that the collection 
> passed as parameter to the block it is always the name and therefore the 
> following test fails:
> testCombinationsAtATimeDoWorksAsExpected
> 
> | combinations |
> 
> combinations := OrderedCollection new.
> 'abc' combinations: 2 atATimeDo: [ :combination | combinations add: 
> combination].
> 
> self assert: 3 equals: combinations size.
> self assert: (combinations includes: #($a $b)).
> self assert: (combinations includes: #($a $c)).
> self assert: (combinations includes: #($b $c)).
> 
> To make it pass I had to make a copy of combination.
> ...
> 'abc' combinations: 2 atATimeDo: [ :combination | combinations add: 
> combination *copy*].
> ....
> 
> Is that the expected behavior? It looks weird to me... I would expect 
> combination to be different collections on each iteration...
> 
> Cheers!
> Hernan.
> 
> On Thu, May 23, 2019 at 1:13 PM Luciano Notarfrancesco via Cuis-dev 
> <cuis-dev at lists.cuis.st <mailto:cuis-dev at lists.cuis.st>> wrote:
> 
>     The method was failing for the corner case of "combinations of 0
>     elements". Here's the fix.
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> 
> 
> -- 
> *Hernán Wilkinson
> Agile Software Development, Teaching & Coaching*
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