How to create const arrays of instances of a class, within that class?

I'm creating my own PHP class. I want to have constant references within that class of instances of that class, like an enumeration.

I keep getting 2 errors: 1. Constants cannot be arrays 2. parse error at line 11 (see below)

What's wrong? Can I seriously not have a constant array? I'm from a Java background...

Here is my code:

class Suit {
    const SUIT_NAMES = array("Club", "Diamond", "Heart", "Spade");
    const COLOURS = array("red", "black");

    const CLUB = new Suit("Club", "black");        // LINE 11
    const DIAMOND = new Suit("Diamond", "red");
    const HEART = new Suit("Heart", "red");
    const SPADE = new Suit("Spade", "black");

    var $colour = "";
    var $name = "";

    function __construct($name, $colour) {
        if (!in_array(self::SUIT_NAMES, $name)) {
            throw new Exception("Suit Exception: invalid suit name.");
        }
        if (!in_array(self::COLOURS, $colour)) {
            throw new Exception("Suit Exception: invalid colour.");
        }
        $t开发者_运维问答his->name = $name;
        $this->colour = $colour;
    }
}

UPDATE:

As of PHP 5.6 it's possible to define a const of type array.

Also as of PHP 7.1 it's possible to define constant visibility (before it would always be public).

ORIGINAL ANSWER:

Neither arrays nor objects can be assigned to constants in PHP. The documentation says it must be a "constant expression." I don't know if they define this term, but they note it excludes, "a variable, a property, a result of a mathematical operation, or a function call. ".

It's unsurprising that constructor calls aren't allowed either, and although array isn't really a function, it's "function-like."

Probably you'll have to do a work-around like the below. We use private static instead of actual constants. This means you need to manually avoid re-assigning, and have to provide a getter (getClub, etc., with naming up to you) if needed.

Also, because you can't assign an object to a static, and PHP doesn't have static initializers, we initialize on demand in the constructor.

An unrelated issue is that you have in_array backwards

class Suit {
    private static $CLUB, $DIAMOND, $HEART, $SPADE;
    private static $SUIT_NAMES = array("Club", "Diamond", "Heart", "Spade");
    private static $COLOURS = array("red", "black");

    private static $initialized = false;

    function __construct($name, $colour) {
        if(!self::$initialized)
        {
            self::$CLUB = new Suit("Club", "black");
            self::$DIAMOND = new Suit("Diamond", "red");
            self::$HEART = new Suit("Heart", "red");
            self::$SPADE = new Suit("Spade", "black");
            self::$initialized = true;
        }

        if (!in_array($name, self::$SUIT_NAMES)) {
            throw new Exception("Suit Exception: invalid suit name.");
        }
        if (!in_array($colour, self::$COLOURS)) {
            throw new Exception("Suit Exception: invalid colour.");
        }
        $this->name = $name;
        $this->colour = $colour;
    }
}