类定义中的PHP字符串连接[重复]

Possible Duplicate:
Initializing PHP class property declarations with simple expressions yields syntax error

Is it possible to achieve the following in PHP 5.2.17 ?

$basePath = '/final';

class Foo {
    public $data = $basePath . '/data';
}

The default values for properties must be constant in the source, e.g. strings and array literals. No expressions.

Use the __construct() method for anything more complicated.