[squeak-dev] The Trunk: Collections-topa.726.mcz
Levente Uzonyi
leves at caesar.elte.hu
Tue Dec 6 21:25:31 UTC 2016
On Tue, 6 Dec 2016, Tobias Pape wrote:
>
> On 06.12.2016, at 21:23, Levente Uzonyi <leves at caesar.elte.hu> wrote:
>
>> On Tue, 6 Dec 2016, tim Rowledge wrote:
>>
>>>
>>>> On 06-12-2016, at 11:08 AM, Levente Uzonyi <leves at caesar.elte.hu> wrote:
>>>> Is there any use of these lists? I mean besides process scheduling.
>>>> I can't imagine a use-case where I would use a LinkedList instead of an OrderedCollection (or another data structure).
>>>
>>> Anywhere that needs frequent adding and removing of items mid-list, or growing/shrinking. Saves constantly making a new array, copying gazillions of OOPs and possibly #become.
>>
>> Using the current implementation, addition might be O(1) if you hold a reference to the internal list node, but removal is O(n) unless you maintain backwards pointers - aka make the list doubly-linked.
>>
>> OrderedCollection is far superior in growing/shrinking (provided it's done at one of its ends), both in term of run time and memory usage, since it needs fewer objects.
>
> Yes.
>
> But sometimes you need a linked list.
Right. But whenever I do, I roll my own because
- most of the time I need a doubly linked list (e.g. LRUCacheHeadNode and
LRUCacheNode)
- I already have a class hierachy to match, so I can't subclass
LinkedList (see ODatedEntry in OCompletion, this is also a doubly linked
list)
> It is not that the trunk _should_ use it but that Squeak programmers _can_ use it.
There must be a reason why it's not being used in the Trunk. :)
Levente
> Let's not impose too much on the programmers. Linked lists are pretty standard :)
>
>
> Best regards
> -Tobias
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