Primary Constructors
| From: | Rob Landers | Date: | Wed, 17 Jun 2026 21:32:05 +0000 |
| Subject: | Primary Constructors | ||
| Groups: | php.internals | ||
| Request: | Send a blank email to internals+get-131353@lists.php.net to get a copy of this message | ||
Hello internals,
I was reminded of my records RFC today, and one of the features of the RFC was "short
constructors" generally called "primary constructors" in C#/Kotlin.
They would look like this:
class Point(public int $x, int $id = 0) extends Base($id);
Which is just sugar for this:
class Point extends Base {
public function __construct(public int $x, int $id = 0) {
parent::__construct($id);
}
}
or this:
class Point extends Base {
public int $x;
public function __construct(int $x, int $id = 0) {
$this->x = $x;
parent::__construct($id);
}
}
A class with a primary constructor *may not* have a defined
__construct function. Any
special initialization must be done with hooks:
class Temperature(
public float $celsius {
set {
if ($value < -273.15) {
throw new ValueError('below absolute zero');
}
$this->celsius = $value;
}
}
) {}
new Temperature(20.0); // ok
new Temperature(-300.0); // ValueError: below absolute zero
I'm sending this email to the list to gather additional feedback before pursuing a formal RFC
proposal.
— Rob