Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:93064
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.223.182 as permitted sender)
MIME-Version: 1.0
Sender: jesseschalken@gmail.com
In-Reply-To: <5724F3F8.5070909@garfieldtech.com>
References: <CAESVnVpa5j=fagr-wm5+DzKKX=wzTN1p8+Kv3-KtGpuyH51b0A@mail.gmail.com>
	<8ea990da-1fe7-256c-4e08-0b30715c8e8a@gmail.com>
	<5724F3F8.5070909@garfieldtech.com>
Date: Wed, 4 May 2016 19:07:59 +1000
Message-ID: <CAF1yvASJG2t_D=XGcfHMb7360dAmGraPNk0Xa2gyqNmn-4G+aQ@mail.gmail.com>
To: Larry Garfield <larry@garfieldtech.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary=001a114f7dbef5d7080532008f8b
Subject: Re: [PHP-DEV] [RFC] Pipe Operator
From: me@jesseschalken.com (Jesse Schalken)

--001a114f7dbef5d7080532008f8b
Content-Type: text/plain; charset=UTF-8

On Sun, May 1, 2016 at 4:05 AM, Larry Garfield <larry@garfieldtech.com>
wrote:

>
> In a way... Sara, this syntax feels like it's only one step removed from
> promises; if any of the chained steps involve IO, it becomes basically what
> promises are for.  Am I barking down the wrong tree, or is there something
> we could connect there?  (I don't mean "reject this in favor of promises",
> but more "is there something we can do here to be forward thinking, since
> lots of people want to see async in core PHP?")
>
>
If you had async/await, you could of course use |> to chain async
operations in an async function by using "await $$" in place of "$$" (since
$$ would be the Promise/Awaitable):

$ret = scandir_async($arg)
       |> array_filter(await $$, ...)
       |> ...


That's quite neat, IMO, and the features are still orthogonal.

You could introduce a new operator to combine the "|>" and "await", say
"a|>", but to add an operator just to combine two others would seem a bit
arbitrary.

You could also generalise |> as a monadic bind (with Promise as the monad
for asynchronicity) but I don't know how that would fit in PHP land without
a meaningful way to turn an expression into a closure. It could be added
later as something like "|>>" if need be.

--001a114f7dbef5d7080532008f8b--