Hi Christoph,

On Sat, 1 May 2021, Thiede, Christoph wrote:

> 
> Hi Levente,
> 
> 
> so what is now the official interface for creating a valid collection of any kind of a certain size n? Shall we always use #ofSize:? Is this something that should be documented in the release notes?

There's no such interface for "a valid collection of any kind", and it's 
not possible to create one, because we have many different collections 
with different properties.
For that reason, Collection doesn't implement #new:, however it inherits 
the method from Behavior, but that is not ideal.

#new: is actually there to support variable classes, so it works well for 
ArrayedCollections, which are variable classes.
Some collections, like Set, Heap, Dictionary, etc. use it to take a 
desired initial capacity. Unfortunately, OrderedCollection also follows 
that pattern.
Some collections cannot implement #new:, like Interval or CharacterSet.

To answer your question, for ArrayedCollections, the method you asked 
about is #new:.
OrderedCollection is a resizable ArrayedCollection: the collection 
an OrderedCollection encapsulates (array) is always an ArrayedCollection.
Its API is similar to ArrayedCollection's but it is not exactly the same.
#new: is different.

As I wrote in another email recently, #new: could have been implemented 
to create a non-empty collection unless the argument is 0. But for some 
reason it wasn't.

#ofSize:, according to its method comment, was created to work around 
that difference:

 	"Create a new collection of size n with nil as its elements.
 	This method exists because OrderedCollection new: n creates an
 	empty collection,  not one of size n."

IMO the best would be to eliminate that difference, but it may be too late 
now, because that would involve breaking all programs having the snippet

 	OrderedCollection new: x

There are 97 potential methods with that pattern in my Trunk image (two of 
those are false positives: the implementors of #ofSize:):

CurrentReadOnlySourceFiles cacheDuring: [
 	| regex |
 	regex := ('({1})\\s+new\\:' format: { (OrderedCollection withAllSubclasses collect: #name) joinSeparatedBy: '|' }) asRegex.
 	SystemNavigation browseAllSelect: [ :method |
 		regex search: method getSource asString  ] ].


Levente

> 
> 
> Best,
> 
> Christoph
> 
> _________________________________________________________________________________________________________________________________________________________________________________________________________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von Taeumel, Marcel
> Gesendet: Dienstag, 27. April 2021 17:07:18
> An: squeak-dev
> Betreff: Re: [squeak-dev] The Inbox: Collections-ul.933.mcz  
> +1 I suppose =)
> It's faster then:
> 
> [OrderedCollection streamContents: [:s | s nextPut: #apple]] bench  
> 
> BEFORE: '2,630,000 per second. 380 nanoseconds per run. 16.13677 % GC time.'
> AFTER: '3,990,000 per second. 251 nanoseconds per run. 15.89682 % GC time.'
> 
> Best,
> Marcel
>
>       Am 31.03.2021 02:19:03 schrieb commits at source.squeak.org <commits at source.squeak.org>:
>
>       Levente Uzonyi uploaded a new version of Collections to project The Inbox:
>       http://source.squeak.org/inbox/Collections-ul.933.mcz
>
>       ==================== Summary ====================
>
>       Name: Collections-ul.933
>       Author: ul
>       Time: 31 March 2021, 2:17:52.141067 am
>       UUID: b290ad2c-2ed0-4d46-b2fe-12545bf5f31c
>       Ancestors: Collections-ul.932
>
>       - use #ofSize: instead of #new: in SequenceableCollection class >> new:streamContents:, so that it creates a stream on a non-empty collection even if the receiver is OrderedCollection.
>
>       =============== Diff against Collections-ul.932 ===============
>
>       Item was changed:
>       ----- Method: SequenceableCollection class>>new:streamContents: (in category 'stream creation') -----
>       new: newSize streamContents: blockWithArg
>
>       | stream originalContents |
>       + stream := WriteStream on: (self ofSize: newSize).
>       - stream := WriteStream on: (self new: newSize).
>       blockWithArg value: stream.
>       originalContents := stream originalContents.
>       + ^originalContents size = stream position
>       + ifTrue: [ originalContents ]
>       + ifFalse: [ stream contents ]!
>       - originalContents size = stream position
>       - ifTrue: [ ^originalContents ]
>       - ifFalse: [ ^stream contents ]!
> 
> 
> 
>