Is automatic initialization of class variables in PHP possible?

Hey, everyone. I couldn't find anything Googling this problem, and I've found really good answers to some questions on SO before, so I'm taking this excuse to join the community.

I'm creating a hierarchy of classes for a PHP project I'm working on, and I'd like to have some variables in the classes initialized within the constructor function without explicitly writing the initialization code. Specifically I want to have the interpreter assume that some of the variables are actually pointers to a certain class. If I could 开发者_JAVA百科do something like C structs, that would be pretty close to what I want.

So far, the only thing I came up with is to explicitly state the variable type within its own name and have the class call an initializing function on each, like;

class A{
  ...
}

class B{
  var $x_A;

  function initVar($var){
    list($varname, $vartype) = split('_',$var);
    $this->$var = new $vartype();
  }

}

And B's constructor calls initVar on all of its get_class_vars(get_class($this)), so anything that inherits from it will do initialization in the same way; obviously including a check on the variable name, a check that the class exists, and a better separation scheme than a single underscore. I just cannot help but think that there is a better way to do this that isn't hardcoding the initialization into the construction function.

If anyone knows of a better way to do this, your help would be much appreciated.

Your method there would probably work, however it could get very tiresome to actually use it. For example, imagine having to reference those variables all the time:

$myObject->account_ServiceAccountType

If you really wanted to go with something like this, perhaps a mapping variable might be useful:

class B {
    public $x, $account;

    private $map = array(
        'x' => 'A',
        'account' => 'ServiceAccountType'
    );

    public function __construct() {
        foreach ($this->map as $var => $class) {
            $this->$var = new $class;
        }
    }
}

You could also try this method out. It uses PHP's magic __get function.

class B {
    private $map = array(
        'x' => 'A',
        'account' => 'ServiceAccountType'
    );
    private $vars;
    public function __construct() {
        $this->vars = array();
        foreach ($this->map as $var => $class) {
            $this->vars[$var] = new $class;
        }
    }

    public function __get($v) {
        return $this->vars[$v];
    }
}

Notice that you don't need to define the class members twice using this method.