(class side)
#new:
(instance side)
#growAtFirst
#growAtLast
#makeRoomAtFirst
#makeRoomAtLast
> On 23 Feb 2015, at 21:15, Mariano Martinez Peck <marianop...@gmail.com> wrote:
>
>
>
> On Fri, Feb 20, 2015 at 5:48 AM, Clément Bera <bera.clem...@gmail.com> wrote:
> It depends on your OrderedCollection implementation.
>
> OrderedCollection has a variable size in memory. When instantiated, it has
> for example 10 slots, and if you have more than 10 objects, it needs to
> change its size to hold more slots.
>
>
> I thought that was the case too, but I cannot find in code what you say.
> OrderedCollection nor it's parents are created with #variableSubclass... As
> you can see, "OrderedCollection isVariable" answers false. So where is that
> "variable size in memory" ?
>
> Thanks,
>
> The current implementation relies on an indirection to an array, when the
> array overflows, the orderedCollection allocates a new bigger array and copy
> the slots from the existing array. There are some heuristics on array size to
> avoid having to grow the array too often.
>
> If you want the shallowCopy to work, you have to use the old implementation
> of OrderedCollection, which encodes in its field directly the values it
> holds. In this case however when the collection overflows you create a new
> orderedCollection so you need to use #become: to migrate references to the
> old orderedCollection to the new one. This used to be a bad idea because the
> become primitive was slow, but since we have Spur, it may be relevant to look
> at it again. This old implementation is more memory efficient too.
>
> 2015-02-20 8:05 GMT+01:00 Marcus Denker <marcus.den...@inria.fr>:
>
>> On 20 Feb 2015, at 06:23, S Krish <krishnamachari.sudha...@gmail.com> wrote:
>>
>>
>> I presumed shallowCopy for literal arrays / OrderedCollection should have
>> been a true copy. Perhaps need to understand this..
>>
>
> OrderdCollection is not just one object, but it holds on to an Array that has
> it’s content. You copy the outside collection object, but share
> the Array.
>
>> shallowCopy
>> "Answer a copy of the receiver which shares the receiver's instance
>> variables. It should never be overridden. I'm invoked from the copy template
>> method. Subclasses that need to specialize the copy should specialize the
>> postCopy hook method."
>> ...
>> <primitive: 148>
>> class := self class.
>> class isVariable
>> ifTrue:
>> [... newObject := class basicNew: index. ....]
>> ifFalse: [newObject := class basicNew].
>> ..
>> whileTrue:
>> [newObject instVarAt: index put: (self instVarAt: index).
>> ...
>> ^ newObject
>>
>> On Wed, Feb 18, 2015 at 10:52 PM, Marcus Denker <marcus.den...@inria.fr>
>> wrote:
>>
>>> On 18 Feb 2015, at 18:13, Cameron Sanders via Pharo-users
>>> <pharo-users@lists.pharo.org> wrote:
>>>
>>>
>>> Date: 18 Feb 2015 18:12:33 CET
>>> Subject: i feel dumb / Pharo3 > OrderedCollection >> do:
>>> From: Cameron Sanders <camsand...@aol.com>
>>> To: Any question about pharo is welcome <pharo-users@lists.pharo.org>
>>>
>>>
>>> I must be making some silly error here that i cannot see clearly. Why does
>>> the following leave anything in the list 'a'? Run it in a workspace. With
>>> or without the shallowCopy, i am left with a list with half of the elements
>>> in it. Always half.
>>>
>>> This version of Pharo3 (21.0) was downloaded last week. I am running on a
>>> Mac.
>>>
>>> Thanks in advance. ... Maybe I just need more coffee.
>>> -Cam
>>>
>>> | a |
>>> a := { #a. #b. #c. #d. } asOrderedCollection.
>>> a shallowCopy do: [ :item | (a includes: item) ifTrue: [ a remove: item ]].
>>> a size
>>>
>>
>> shallowCopy is not enough… OrderedCollection is made up of an internal array.
>>
>> #copy does the right thing, just copies the array:
>>
>> postCopy
>> array := array copy
>>
>> and for Array, copy is a shallowCopy.
>>
>> Marcus
>>
>>
>>
>>
>
>
>
>
>
> --
> Mariano
> http://marianopeck.wordpress.com
