Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:93335
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: unknown (pb1.pair.com: domain php.net does not designate 212.27.42.2 as permitted sender)
To: Sara Golemon <pollita@php.net>
References: <CAESVnVpa5j=fagr-wm5+DzKKX=wzTN1p8+Kv3-KtGpuyH51b0A@mail.gmail.com>
 <ddcfc338-a2fb-a06f-36ef-30e105772779@gmail.com>
 <CAESVnVr07J9UF3Dh7a1rMudMmQjeYuayvoT8Rmde+rfCBK6vnQ@mail.gmail.com>
 <452ddb93-1f47-1d0f-4f24-bedbff506b27@gmail.com>
 <CAESVnVqohR7rkaJASZ0rFuAD6GEiasqbAak-fJB3+K2vSKqHFQ@mail.gmail.com>
 <98.61.11104.A1D41375@pb1.pair.com>
 <7c94ca37-e188-dd2b-a66f-bb63bf03041a@gmail.com>
 <1463008795.1856219.605250569.74618FC4@webmail.messagingengine.com>
 <CANaX5nekRmhNKmY78tHRrev0_B3a-faRsQ8Jf=yA-jCkEP5-Ew@mail.gmail.com>
 <CAKrrN64bu+T0Sv4V6mo7i1cRYAh1W8Kx8tQ_rqQmZagXBTqKuQ@mail.gmail.com>
 <92E7F8A8-0845-48A7-91B1-9554C5F66C9D@zend.com>
 <CAESVnVq14EL_hJ=G_QTpvbzQhxP-Auy5p2rH9yja8bABsVr_sQ@mail.gmail.com>
 <879feadf-c04e-c0de-826b-110b3eb4e22f@php.net>
 <CAESVnVoW8+c1iDHxc52o2cxhiuBn7Z5Ag0+hsh1xKv73kUbBNQ@mail.gmail.com>
 <ff1cb37c-923b-f9c6-e326-c75a4f3e1623@php.net>
 <CAESVnVrn6iSZ7KWVDpcJ-Fw7k9NZnUbHUs88RBOBPsENg_sVWQ@mail.gmail.com>
Cc: Zeev Suraski <zeev@zend.com>, Quim Calpe <quim@kalpe.com>,
 "davey@php.net" <davey@php.net>, Larry Garfield <larry@garfieldtech.com>,
 "internals@lists.php.net" <internals@lists.php.net>
Message-ID: <85ec320c-b8d6-1cc8-2059-7b8dfa6589e2@php.net>
Date: Sun, 15 May 2016 02:42:42 +0200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101
 Thunderbird/45.0
MIME-Version: 1.0
In-Reply-To: <CAESVnVrn6iSZ7KWVDpcJ-Fw7k9NZnUbHUs88RBOBPsENg_sVWQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 8bit
Subject: Re: [PHP-DEV] [RFC] Pipe Operator
From: francois@php.net (=?UTF-8?Q?Fran=c3=a7ois_Laupretre?=)

Le 13/05/2016 à 20:16, Sara Golemon a écrit :
>> for a potential solution to such a long-time issue as argument ordering
>> sadness, IMHO, it's worth the pain. I am currently doing it and I'll send
>> you the list when it is ready.
>>
> Awesome.  Even if not used in this feature, it could potentially be
> useful elsewhere.  I hope you put it in a public gist or similar for
> posterity.

After a quick check of every functions available in the PHP distrib, 
only 55 functions should insert the lhs in a position different from 0 
(first argument). From these 55 functions, 4 must not be used in a 
pipeline and, for the remaining 51, the lhs must be inserted as 2nd, 
3rd, or 4th argument. The list and positions to use are available at :

http://tekwire.net/joomla/projects/ideas/pipe-operator

So, the logic would be :

- if the function accepts 0 mandatory argument, it cannot be used in a 
pipeline,
- if the function is in the table referenced above, use the position 
from the table,
- else, insert the lhs as 1st arg.

For internal functions, we can easily use some unused part of the 1st 
arginfo element to store the position. The default will remain 0, which 
doesn't require any change in current arginfo declarations. We'll just 
have to define a new ZEND_BEGIN_ARG_INFO_xxx macro with an explicit 
position. This macro will be used for the 55 functions requiring a 
specific non-default position. -1 will be used to mark a function as 
unusable in a pipeline.

Once again, I think that argument ordering is a very important issue 
and, here, we have an unique occasion to solve it for a rather moderate 
price, since every functions have been audited.

Another issue is caused by the sort functions returning the sorted array 
by reference. The problem is the same with or without '$$'. In practice, 
these functions cannot be used in a pipeline. So, either we change their 
behavior to be different when used in a pipeline, which is weird but 
allows an intuitive '|> sort() |>' notation, or we need to define a new 
set of functions returning sorted arrays. None of these is perfect but 
we'll have to propose a solution, as sorting is essential when driving 
an array through a pipeline.

Regards

François