Expressions And Operators: Member Selection

The operator -> is used to access instance properties and instance methods on objects.

class IntBox {
  private int $x;

  public function __construct(int $x) {
    $this->x = $x; // Assigning to property.
  }

  public function getX(): int {
    return $this->x; // Accessing property.
  }
}

<<__EntryPoint>>
function main(): void {
  $ib = new IntBox(42);
  $x = $ib->getX(); // Calling instance method.
}

Null Safe Member Access

The operator ?-> allows access to objects that may be null.

If the value is null, the result is null. Otherwise, ?-> behaves like ->.

function my_example(?IntBox $ib): ?int {
  return $ib?->getX();
}

Note that arguments are always evaluated, even if the object is null. $x?->foo(bar()) will call bar() even if $x is null.

XHP Attribute Access

The operator ->: is used for accessing XHP attributes.