factory.php

<?php

class NF_Factory
{
  protected $_form;
  
  public function __construct( $id )
  {
    $this->_form = new NF_Form( $id );
    
    return $this;
  }
  
  public function get()
  {
    return $this->_form;
  }
  
  public function get_field( $id )
  {
    $form_id = $this->_form->get_id();
    return new NF_Field( $id, $form_id );
  }
}