Class Variable Reference

[rpanning]

I'm trying to concat two class variables to one but I'm not sure if it is supposed to work. I can't get it to work. Ex:

class Test
{
    var $foo;
    var $bar;
    var $both;

function Test()
{
    $this->foo = 'abc';
    $this->bar = '123';
    $this->both = &$foo . &$bar;
}
}

Is this supposed to work or is it a limit by PHP? Thanks