How Can I Properly Initialize Static Variables in PHP?

Initializing Static Variables in PHP

When initializing static variables, you may encounter syntax errors like the one exemplified in the given code snippet. This is because PHP cannot parse complex expressions within the variable initializer.

Alternative Initialization Methods

To resolve this issue, consider using the following alternative methods:

• Separate Initialization: Define your static variable as usual, then initialize it using a separate statement outside of the class definition.

class Registration {
  static $dates;
}
Registration::$dates = array(
  'start' => mktime(0, 0, 0, 7, 30, 2009),
  'end' => mktime(0, 0, 0, 8, 2, 2009),
  'close' => mktime(23, 59, 59, 7, 20, 2009),
  'early' => mktime(0, 0, 0, 3, 19, 2009),
);

• Initialization Function: Create a static function within the class to handle the initialization.

class Registration {
  private static $dates;

  static function init() {
    self::$dates = array(
      'start' => mktime(0, 0, 0, 7, 30, 2009),
      'end' => mktime(0, 0, 0, 8, 2, 2009),
      'close' => mktime(23, 59, 59, 7, 20, 2009),
      'early' => mktime(0, 0, 0, 3, 19, 2009),
    );
  }

  // Call the init function to initialize the variable
  public function __construct() {
    static::init();
  }
}

PHP 5.6 Support

PHP 5.6 introduced limited support for non-trivial expressions in static variable initializers. However, it is recommended to use the aforementioned methods for clarity and compatibility with earlier versions of PHP.

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