是否可以在PHP中使用class作为变量？

I have a class as follows:

class Integer {

private $variable;

public function __construct($variable) {
   $this->varaible = $variable;
}

// Works with string only
public function __isString() {
 return $this->variable;
}

// Works only, If Im using the class as a function (i must use parenthesis)
public function __invoke() {
 return $this->variable;
}

}


$int = new Integer($variable);

I would like work with class as with variable like:

$result = $int + 10;

I don´t known, how can I return $int; ?

PHP does not support overloading operators (which is the technical thing you're looking for). It doesn't know what to do with + when one of the operands is a class Integer, and there's no way to teach PHP what to do. The best you can do is implement appropriate methods:

class Integer {
    ..
    public function add(Integer $int) {
        return new Integer($this->variable + $int->variable);
    }
}

$a = new Integer(1);
$b = new Integer(2);
echo $a->add($b);

Yes, see Example 4 of php's call_users_func() page;

<?php

class myclass {
    static function say_hello()
    {
        echo "Hello!
";
    }
}

$classname = "myclass";

call_user_func(array($classname, 'say_hello'));
call_user_func($classname .'::say_hello'); // As of 5.2.3

$myobject = new myclass();

call_user_func(array($myobject, 'say_hello'));

?>

public function __construct($variable) { $this->varaible = $variable; } are this typo or not? on $this->varaible ?