constant scalar expressions

Hey List,

Just glanced over the Constant Scalar Expressions
RFChttps://wiki.php.net/rfc/const_scalar_exprsand just wanted to
briefly share a couple of thoughts.

This brings initialization of constants, and default values for arguments,
very close to "full" PHP syntax - but not quite.

Did you consider supporting non-scalar values?

Did you consider permitting e.g. function calls in declarations?

And finally, and perhaps most importantly, did you consider lazy (late,
on-access) evaluation of expressions?

I could picture something like the following would go a long way towards
mitigating problems that are currently solved with frameworks and/or oodles
of boilerplate, e.g. when you have a container full of services or
configuration settings etc. without using a framework:

class MyApp {
private $_connection;
public function getConnection() {
if (!isset($this->_connection)) {
$this->_connection = new DatabaseConnection(...);
}
return $this->_connection;
}

public function setConnection(DatabaseConnection $connection) {

    $this->_connection = $connection;

}

}

$app = new MyApp;
$db = $app->getConnection(); // lazy initialization

Suppose you had full support for PHP expressions with lazy initialization:

class MyApp {
public $connection = new DatabaseConnection(); // lazy
}

$app = new MyApp;
$db = $app->connection; // lazy initialization

It seems like this would mitigate the need for a lot of framework and/or
boilerplate to achieve lazy construction?

Just putting that out there.

• Rasmus Schultz