类的扩展和命名空间

类的扩展

// __get()
class user
{
    private array $data =[
        'age' => 18,
    ];
    public function __get($name)
    {   
        $a = array_key_exists($name, $this->data);
        return $a ? $this->data[$name] : "$name 属性不存在" . '<br>';
    }
    // set()
    public function __set ($name,$value) {
        $this->$name = $value;
    }
// __call()
public function __call($name, $age)
{
    printf('%s , %s', $name, $age);
}
// __callstatic
public static function __callstatic($name, $age)
    {
        printf('%s, %s', $name, $age);
    }
}
class stu
{
        protected string $name;
        private $age = 18;
    // __construct()
    public function __construct($name)
    {
        $this -> name =$name;
    }
}

命名空间

namespace one;
class a
{
    public static function a1()
    {
        return __METHOD__;
    }
}
echo a::a1() . '<br>';
echo two\a::a1() . '<br>';
echo \one\two\a::a1() . '<br>';
use \one\two\three\a as UserIndex;
echo a::a1() . '<br>';
namespace one\two;
class a
{
    public static function a1()
    {
        return __METHOD__;
    }
}