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Date: Wed, 2 Dec 2020 17:24:33 +0000
Message-ID: <CAJ0sH8aadzR=BsEY+Nn2-vyr=8LTVqCbWietbbC1zc=LHFzGkw@mail.gmail.com>
To: internals@lists.php.net
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Subject: Suggestion: Inconsistency: Allow array spread operator to work on
 string keys
From: florian.stascheck@gmail.com (Florian Stascheck)

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Hello!

With PHP8 released and the named arguments RFC being implemented, there's
now an inconsistency in how the spread operator works.

Historically, the spread operator was first used in PHP 5.6 for arguments:

function php56($a, $b) {
  return $a + $b;
}
$test = [1, 2];
php56(...$test) === 3;

Then, with PHP 7.4, the spread operator was also introduced for array
literal syntax:

$parts = ['apple', 'banana'];
$fruits = ['strawberry', ...$parts, 'grape'];
$fruits == ['strawberry', 'apple', 'banana', 'grape'];

The RFC back then explicitly excluded [1] string keys, to make the
functioning of the spread operator consistent with how it's used for
function arguments.

Now, in PHP8 we can do:

function php8(int $a, int $b): int {
  return $a + $b;
}
$test = ['b' => 40, 'a' => 2];
php8(...$test) === 42;

However, string keys in array literals are still not possible. So the
limitation that once was introduced for consistency now led to an
inconsistency.

I suggest to allow string keys to also be used in array literals:

$template = ['created_at' => time(), 'is_admin' => 1];
$db_rows = [
  ['name' => 'Alice', 'email' => 'alice@example.org', ...$template],
  ['name' => 'Bob', 'email' => 'bob@example.org', ...$template],
];

What's your feedback on that? Do you see any obvious problems with that
approach? I searched through the archives and couldn't find this problem
being mentioned before.

-Florian

[1]: https://wiki.php.net/rfc/spread_operator_for_array#string_keys

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