class Filter{
    private $data = array();
    public function __construct($post){
    $this->data = $post;
    }
    function __get(){
    return (!empty($this->data))? $this->data : print "Ничего!";
    }
    function __set(){
     if(!empty($this->data)){
         foreach($this->data as $name){
             strip_tags($name);
     }
     }
     else{
         print "Всё плохо!\n";
     }
   }
}
if(!empty($_POST['go'])){
    $filter = new Filter;
    var_dump($filter->input_filter());
}