Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:84445
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
To: internals@lists.php.net,Rowan Collins <rowan.collins@gmail.com>
Message-ID: <54FCAB09.80903@luni.fr>
Date: Sun, 08 Mar 2015 21:03:21 +0100
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.4.0
MIME-Version: 1.0
References: <CAGnBX03-qsCySW0qOZFWk60p1MaJe-ed1DN+z2fjAqJJLqu8fg@mail.gmail.com> <CAEPJdu=L2Rx68epUw7NxqrKGcn5Y8Tx+awMLuR8NXG4rct76YA@mail.gmail.com> <CAGnBX01sN6F1t3ntT4qX3a65qxYO3T2Au+8PvWdkrNCX0T-hFw@mail.gmail.com> <54FC29B4.4000105@luni.fr> <54FC5A71.7000905@gmail.com> <54FC6EAA.3050100@luni.fr> <54FC8F5F.3020107@gmail.com>
In-Reply-To: <54FC8F5F.3020107@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] Feature request and RFC
From: gregory@luni.fr (=?UTF-8?B?R3LDqWdvcnkgUGxhbmNoYXQ=?=)

Le 08/03/2015 19:05, Rowan Collins a écrit :
> On 08/03/2015 15:45, Grégory Planchat wrote:
>> class BarSortable implements Sorter
>> {
>>     public function sort(Sortable $collection)
>>     {
>>         $previousKey = null;
>>         $previousElement = null;
>>
>>         foreach ($collection as $key => $element) {
>>             if ($previousKey === null) {
>>                 $previousKey = $key;
>>                 $previousElement = $element;
>>                 continue;
>>             }
>>             if ($previousElement < element) {
>>                 $collection->swap($previousKey, $key);
>>             }
>>
>>             $previousKey = $key;
>>             $previousElement = $element;
>>         }
>>     }
>> }
>
> Unfortunately, this won't actually sort the array - it only makes one
> check of each value, so [4, 1, 2, 3, 5] would come out as [4, 2, 3, 1,
> 5], when it should be [5, 4, 3, 2, 1] (your < sign means you're sorting
> largest value first). It's *almost* like a bubble sort, though (you keep
> swapping things until you know that there's no more swaps to be made),
> which is the simplest but also least efficient way of sorting a list.
>
> I think insertion sort, which is simple and efficient for small lists,
> could be done with iteration plus a single callback of
> "insertElementAt". For larger lists, though, you're going to want a
> quicksort, and I can't quite picture what callbacks that would need to
> run on the collection as it went; it ultimately requires some way of
> partitioning the list into multiple pieces.
>
> Regards,
>

Yes you're right, I wrote up this example a bit too fast, with lots of 
mistakes. I since went over my proposal and fixed them.

It is in fact a bit too large for sending it on internals@ and related 
to another proposal I made here, so I wrote it on a github repository 
and merged it with the other proposal:

https://github.com/gplanchat/php-oop-api/blob/master/doc/sorting.md

I think this implementation is a bit more solid.

The point made after the SortableAggregate and SorterAggregate is that a 
userland class may encapsulate the real collection. Instead of making 
decorators over and over again - which would be a performance hurdle - I 
brought the idea of passing the real sorter via a visitor pattern.

I thought of this implementation to find a solution for OO API with 
arrays, as you can read here:

https://github.com/gplanchat/php-oop-api/blob/master/doc/array.md
https://github.com/gplanchat/php-oop-api/blob/master/doc/array-sorter.md

Grégory Planchat