Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:103477
MIME-Version: 1.0
References: <tencent_0F5DD6190D2239856E68286D@qq.com> <CAF+90c_fM3Fk5dhzEHLsPPSun0R0X5NnJNyzONBheE9YMYg6DA@mail.gmail.com>
In-Reply-To: <CAF+90c_fM3Fk5dhzEHLsPPSun0R0X5NnJNyzONBheE9YMYg6DA@mail.gmail.com>
Date: Wed, 21 Nov 2018 22:46:42 -0700
Message-ID: <CAFMT4NrdRxx=kb8VxOL5nhdVrBY6dbjtY0t-hpSVZ9wE7_i4XA@mail.gmail.com>
To: Nikita Popov <nikita.ppv@gmail.com>
Cc: me@jhdxr.com, internals <internals@lists.php.net>
Content-Type: text/plain; charset="UTF-8"
Subject: Re: [PHP-DEV] [RFC] Spread Operator in Array Expression
From: levim@php.net (Levi Morrison)

On Wed, Nov 21, 2018 at 12:31 PM Nikita Popov <nikita.ppv@gmail.com> wrote:
>
> On Mon, Nov 19, 2018 at 9:26 AM CHU Zhaowei <me@jhdxr.com> wrote:
>
> > Hi internals,
> >
> > I'd like to start the discussion for [RFC: Spread Operator in Array
> > Expression](https://wiki.php.net/rfc/spread_operator_for_array). In
> > short, this is a syntax similar to argument unpacking, but for array.
> >
> > You can find the implementation [here](
> > https://github.com/php/php-src/pull/3640). It's still WIP, but I'll
> > finish it in the next following weeks.
>
>
> This looks reasonable to me. The array_merge() behavior is certainly the
> one I would (in PHP) expect intuitively, and it is likely the most useful
> one as well, striking a balance between behavior useful for pure vectors
> and pure dictionaries (and falling short if it's not either ... as is usual
> in PHP).
>
> Nikita

I think we have `+` and `array_merge` already. What we *don't* have is
something that concatenates solely with values and ignores keys, at
least not in a single step. I think `...` can be that operator,
precisely because this is what it does for function calls as well.

In other words, this results in a completely sequentially ordered
array, regardless of the key structure of `$rest`, and does not
overwrite positions 0 and 1:

    $data = [$first, $second, ...$rest];

Those are the semantics that I would like. I think `+` and
`array_merge` serve the other cases, so no need to deviate from how
this works with function calls, which are obviously positional and
will not overwrite previous values.