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To: "Clint Priest" <cpriest@warpmail.net>,
	"PHP Developers Mailing List" <internals@lists.php.net>
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Date: Sun, 27 Sep 2009 13:43:51 +0300
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Subject: Re: [PHP-DEV] Bitwise Declaration of Flags
From: sv_forums@fmethod.com ("Stan Vassilev")

> Are there any plans to allow bitwise declaration of flags?
>
> Example:
>
> class foo {
>    const FLAG_1 = 1;
>    const FLAG_2 = 2;
>    const FLAG_3 = 4;
>
>    private $Flags = self::FLAG_1 | self::FLAG_3
> }


Hi,

This is not allowed since declaration values should be resolvable at compile 
time. I.e. they can not be an expression, but only a value literal.

While technically expression folding is possible, it's not implemented in 
any part of the PHP engine (AFAIK), and I don't think it's planned any time 
soon.

To do what you want, initialize the value in the constructor:

class foo {
    ...
    private $flags;

    function __construct()
    {
        $this->flags = self::FLAG_1 | self::FLAG_3;
    }
}

Regards,
Stan Vassilev