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Date: Mon, 28 Jun 2021 22:42:31 +0200
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To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] Pipe Operator, take 2
From: olleharstedt@gmail.com (=?UTF-8?Q?Olle_H=C3=A4rstedt?=)

2021-06-28 22:12 GMT+02:00, Larry Garfield <larry@garfieldtech.com>:
> On Mon, Jun 28, 2021, at 3:04 PM, Rowan Tommins wrote:
>> On 28/06/2021 20:25, Olle H=C3=A4rstedt wrote:
>> > Usage (ignoring the pesky undefined constant warnings ><):
>>
>>
>> Unfortunately, you can't ignore those warnings; not least because
>> they're fatal errors in PHP 8, as they frankly should have been in PHP 3=
.
>>
>> You can use our current ugly callable syntax (strings and two-element
>> arrays); you can tackle the complexity of unifying functions with
>> constants, and methods with properties (as Levi explained in the other
>> thread); or you can add a dedicated callable syntax, which the PFA
>> proposal gets us with bells on.
>>
>> Regards,
>
> I think that's a pretty good summary.  There's nothing that pipes or
> partials do that you couldn't emulate in user-space today (really, since =
5.3
> is you really wanted to).  The emulation is just butt-ugly and slower, wh=
ich
> is why most people don't do it except in very specific cases or if they h=
ave
> a user-space library available that makes it slightly less butt-ugly.
>
> The purpose of PFA and pipes (and short functions, and auto-capture
> closures, and basically everything else I've been talking about all year)=
 is
> to make those things prettier and as fast as reasonable, which makes usin=
g
> those techniques more natural.  Once you start down that path, though,
> there's really no usable solution before you get down as far as... PFA an=
d
> Pipes in their current form.
>
> --Larry Garfield

The challenge is to write something that's pretty enough to be
considered idiomatic. :) The pipe operator in OCaml is defined by one
line:

    let (|>) v f =3D f v

It wasn't always part of core, but eventually it was so common, it got
included by default. Same could happen with a pipe() function in PHP,
without the pipe operator, or that the function becomes so common, a
new keyword is added instead: `pipe`. But it could probably not happen
with a Pipe object requiring you to write ->pipe() at every step -
it's too much ceremony and boilerplate.

By the way, that's alternative 5) New keyword `pipe` to make the
warning about constants shut up in a certain scope. Plus some other
magic to allow nice chaining. ^^

Olle