Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:97891
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.215.66 as permitted sender)
MIME-Version: 1.0
Sender: morrison.levi@gmail.com
In-Reply-To: <52a7238f-af22-8960-c829-b1d4ba1bbfdc@free.fr>
References: <CAESVnVoBrtfWGF-Be+uXWwLNO3=JzuLBXyhW0Dpo-NvoskofQw@mail.gmail.com>
 <CAFMT4Np4zPjDKswAcjA_TkJ70yMEzrRH2SJk_h1k26HnjMyuoA@mail.gmail.com>
 <f9f973f2-7d39-9ebd-bcb1-6ac1c69af962@free.fr> <CAFMT4NpjNOzdtH8LcVzav_5=J2ap8iyO1iAbVykkVHZ=Mx44dA@mail.gmail.com>
 <52a7238f-af22-8960-c829-b1d4ba1bbfdc@free.fr>
Date: Fri, 20 Jan 2017 07:43:01 -0700
Message-ID: <CAFMT4Nr9u-9m8NLWbE94fgUL7zvkzeBvv=R7O+fFB3k_2a-OeQ@mail.gmail.com>
To: =?UTF-8?Q?Fran=C3=A7ois_Laupretre?= <flaupretre@free.fr>
Cc: internals <internals@lists.php.net>, Sara Golemon <pollita@php.net>
Content-Type: multipart/alternative; boundary=001a11402332b9698f054687aa56
Subject: Re: [PHP-DEV] Pipe Operator v2
From: levim@php.net (Levi Morrison)

--001a11402332b9698f054687aa56
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable

On mobile, sorry for top posting.

Multiple $$ means the resulting closure will accept multple arguments.

I'm definitely against dropping the ($$) on the right hand side because it
would use non standard symbol lookup rules.

    $x =3D trim;

This normally will look up a constant, and then apply barewords if it
doesn't exist. Let's not go down the road of special casing things.

On Jan 20, 2017 3:53 AM, "Fran=C3=A7ois Laupretre" <flaupretre@free.fr> wro=
te:

> Le 19/01/2017 =C3=A0 22:53, Levi Morrison a =C3=A9crit :
>
>> On Thu, Jan 19, 2017 at 11:12 AM, Fran=C3=A7ois Laupretre <flaupretre@fr=
ee.fr>
>> wrote:
>>
>>> Le 19/01/2017 =C3=A0 13:54, Levi Morrison a =C3=A9crit :
>>>
>>>> The `|>` symbol would be the piping operator with these semantics:
>>>>       1. Evaluate the left-hand side.
>>>>       2. Evaluate the right-hand side. Assert that the result is
>>>> callable.
>>>>       3. Pass the result from 1. as the single argument to 2.
>>>>
>>>
>>> May I suggest extending your 3rd rule to : when the right hand side has
>>> the
>>> form of a function call, insert the result from 1. as first argument of
>>> 2.
>>> This way, right hand side may specify additional arguments
>>>
>> If we only had `|>` this may be good but since we are also proposing
>> `$$` then this renders your suggestion unnecessary:
>>
>>      $string |> trim($$)
>>
>> Would work just fine with no performance overhead.
>>
>> Additionally, you could write:
>>
>>      $input |> array_map($fn, $$)
>>
>> Or:
>>
>>      $input |> array_filter($$, $fn)
>>
>> Basically, `$$` gives the flexibility of passing additional arguments
>> and keeps `|>` simple. No need for additional rules for `|>`.
>>
>
> Right, I just suggest to make the '$$' optional when used as first arg of
> a rhs call. Except complex cases like array_xx() functions which will
> generally require an explicit '$$', most cases will feature a '$$' as fir=
st
> arg of a function call. This may be considered as better because more
> explicit, but I think the case is prominent enough to justify this
> 'shortcut'.
>
> Another question: Will you accept several occurences of '$$' in a RHS ?
>
> Last, a cosmetic suggestion : replace '$$' with '$<' (more explicit as
> 'input data', imo).
>
> Regards
>
> Fran=C3=A7ois
>

--001a11402332b9698f054687aa56--