class PageController {
  var $person; #$person is used by the HTML page
  var $errs;
  function PageController() {
    $action = Form::getParameter('cmd');
    $this->person = new Person();
    $this->errs = array();
    if ($action == 'save') {
       $this->parseForm();
       if (!this->validate()) return;
       NewsletterLogic::subscribe($this->person);
       header('Location: confirmation.php');
       exit;
    }
  }
  function parseForm() {
    $this->person->name = Form::getParameter('name');
    $this->person->birthdate = Util::parseDate(Form::getParameter('birthdate');
    ...
  }
  function validate() {
    if ($this->person->name == '') $this->errs['name'] = FORM_MISSING;
    #FORM_MISSING is a constant
    ...
    return (sizeof($this->errs) == 0);
  }
}