Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:41633
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.128.189 as permitted sender)
DomainKey-Status: bad
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=message-id:date:from:user-agent:mime-version:to:cc:subject
         :references:in-reply-to:content-type:content-transfer-encoding;
        b=XQYIGw55ztHPQxS7TO1KF++0AWX7xbiA/DgzMM+UW7Jz6N+IPKqKVgyd5yByVzNQ86
         a/N5tHPR5mxXQUBS2xFWZM78q1PaDgJz+T7mDuLSME6FDiSaUShSofsd5IILc2pTRr07
         kc40AwwZNgOutQRikLWxSG27KpLKQDZ+gNvRs=
Message-ID: <491011AC.8030609@gmail.com>
Date: Tue, 04 Nov 2008 11:11:08 +0200
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b1pre) Gecko/20081006 Shredder/3.0a3
MIME-Version: 1.0
To: Marcus Boerger <helly@php.net>
CC: 'PHP Internals' <internals@lists.php.net>
References: <490F13A2.1020809@gmail.com> <154582775.20081103164129@marcus-boerger.de>
In-Reply-To: <154582775.20081103164129@marcus-boerger.de>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [PHP-DEV] [RFC] Iteration tools
From: ionut.g.stan@gmail.com (Ionut Gabriel Stan)

On 11/3/2008 17:41, Marcus Boerger wrote:
> Hello Ionut,
>
>    some remarks about your proposal:
>
> 1) You can turn any array into a Traversable using
> (Recursive)ArrayIterator. Though this solution is still slow. The issue is
> that the c-level code needs to verify the current pointer every single time
> it uses it and that means traversing the array from the beginning. That
> said we might want to:
> a) Optimize that for cases where we don't have to. Basically when nothing
> else is pointing to the array (refcount==1) we know when the array can be
> changed and do not have to verify it always.
> b) provide a lower level array to traversable mechanism that operates on
> the current pointer provided by the array itself. That way having no need
> to verify that pointer at all.
>
> 2) Ther are iterator_apply(), iterator_to_array(), iterator_count()
> The first can be used for a lot of the things you were looking for,
> especially when used together with lambdas. Also not that you can use it to
> pass the iterator itself to the function being called easily.
>
> Still a few of the things you mention can be implemented faster in the same
> way iterator_apply() was done. In fact the code can be based on the lovel
> c-implementation provided.
>
> marcus
>
> Monday, November 3, 2008, 4:07:14 PM, you wrote:
>
>    
>> Hello everybody,
>>      
>
>    
>> As a result of the advice given in the thread "array_key_exists BC
>> break", I have written an
>> RFC concerning some higher order functions that, I believe, could a
>> helpful addition to the language.
>>      
>
>    
>> Please note that I'm a userland developer and have no clue about PHP
>> internals so please
>> forgive any stupidities I might have said in the RFC and make the
>> appropriate corrections.
>> That also means that, if positive feedback is received, this RFC needs a
>> developer with PHP
>> internals knowledge to implement it.
>>      
>
>    
>> The RFC can be found here:  http://wiki.php.net/rfc/iteration-tools
>>      
>
>    
>> Hoping that I've made sense in what I wrote there, please feel free to
>> comment as you like.
>>      
>
>    
>> Regards,
>> Ionut
>>      
>
>
>
>
>
> Best regards,
>   Marcus
>
>
>    
Hi Marcus,

Thanks for your answer.

I had no idea there is an iterator_apply() function, I did a little bit 
of search after you mentioned it
and found it nowhere in the docs but apparently it is present in my 
5.2.6 installation. iterator_to_array()
and interator_count() are very useful functions which I had knowledge of 
but forgot about them in my wiki.

I recognize that my proposal can easily be implemented in userland code 
with the classes and functions
that we already have, as you mentioned already. The only real advantage 
is the speed given by the C level
code and a common, standard API for array and Traversables. This way 
array_map(), array_reduce() and
the like could be deprecated. I always have to look in the docs or pay a 
little attention to my IDE to see
what param goes where.

Anyway, I see there's nobody else that would like this but it's ok, at 
least now we have namespaces so that
I don't have to come up with ugly names like my_map() for these kind of 
helper functions.


Cheers,
Ionut