尝试使用方法外部的dirname（）初始化此公共类变量时出错

Question

Why can't I set a public member variable using a function?

<?

class TestClass {

    public $thisWorks = "something";

    public $currentDir = dirname( __FILE__ );

    public function TestClass()
    {
        print $this->thisWorks . "
";
        print $this->currentDir . "
";
    }

}

$myClass = new TestClass();

?>

Running it yields:

Parse error: syntax error, unexpected '(', expecting ',' or ';' in /tmp/tmp.php on line 7

Answer 1

You cannot have expressions in the variable declarations. You can only use constant values. The dirname() may not appear in this position.

If you were to use PHP 5.3 you could use:

  public $currentDir = __DIR__ ;

Otherwise you will have to initialize $this->currentDir in the __constructor.