class PersonWriter{
 public function writeName(Persion $p){
  print $p->getName()."\n";
 }
 public function writeAge(Persion $p){
  print $p->getAge()."\n";
 }
}

class Person {
 private $writer;
 function __construct(PersonWriter $writer;){
  $this->writer = $writer;
 }
 function __call($methodname,$args){
  if(method_exists($this->writer,$methodname)){
   return $this->writer->$methodname($this);
  }
 }
 //...
}

$person = new Person(new PersonWriter());
$person->writeName();