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Date: Sat, 17 Jul 2021 16:48:04 +0200
Message-ID: <CADyq6sJFmNiVSJPTGnjQOXGMFeezRLUCPbM6rJ3jooAVKPfXxA@mail.gmail.com>
To: Larry Garfield <larry@garfieldtech.com>
Cc: php internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [Vote] Pipe operator v2
From: ocramius@gmail.com (Marco Pivetta)

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Hey Larry,

I just voted "NO" on this: it took me a long time to decide, because I've
been vouching for pipe-alike operators myself for a while.

The reason why I voted "no" is that this is feasible with a `pipe(callable
$first, callable ...$piped)` function, without having to add syntax/AST for
it.

Type safety for such a closure would still be very messy, but feasible with
some macro-based templating of docblocks.

The simplistic approach to this is simple composition (the `.` you
mentioned):

```php
/**
 * @template TIn of mixed
 * @template TOut of mixed
 *
 * @param callable(TIn): TIntermediate $first
 * @param callable(TIntermediate): TOut $piped
 *
 * @return callable(TIn): TOut
 * @return TOut
 */
function pipe(callable $first, callable $piped): callable
{
}
```

 Pol Dellaiera  (https://github.com/drupol) has done a lot of work around
this stuff, specifically the type inference bit, in
https://github.com/loophp/combinator , so I see hope to get better types at
a later stage.

Therefore:

 * userland runtime **implementation** is trivial
 * userland type-safe definition is non-trivial, but not insurmountable


Marco Pivetta

http://twitter.com/Ocramius

http://ocramius.github.com/


On Tue, Jul 6, 2021 at 7:13 PM Larry Garfield <larry@garfieldtech.com>
wrote:

> I have opened the vote on the Pipe operator RFC:
>
> https://wiki.php.net/rfc/pipe-operator-v2
>
> The vote will close on 20 July.
>
> --
>   Larry Garfield
>   larry@garfieldtech.com
>
> --
> PHP Internals - PHP Runtime Development Mailing List
> To unsubscribe, visit: https://www.php.net/unsub.php
>
>

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