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Date: Thu, 19 Jan 2017 14:53:39 -0700
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To: =?UTF-8?Q?Fran=C3=A7ois_Laupretre?= <flaupretre@free.fr>
Cc: Sara Golemon <pollita@php.net>, PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Pipe Operator v2
From: levim@php.net (Levi Morrison)

On Thu, Jan 19, 2017 at 11:12 AM, Fran=C3=A7ois Laupretre <flaupretre@free.=
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 t=
he
> 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 `|>`.