How to use Symfony2 Form Component Standalone

sf2_standalone_form.php

<?php
namespace Standalone\Form;

use \Symfony\Component\HttpFoundation as SHttp;
use \Symfony\Component\Form as SForm;
use \Symfony\Component\DependencyInjection as SDI;
use \Symfony\Bridge as SBridge;

//Register all your autoloaded functions here
//...

//This is a Doctrine mapped entity class
//This should be placed in a separate file
/**
 * @Table(name="person")
 */
class Person {
	/**
	 * @Id
	 * @GeneratedValue
	 * @Column(type="integer")
	 * @var string
	 */
	protected $id;
	public function getId() { return $this->id; }

	/**
	 * @Column(type="string", unique=true)
	 * @var string
	 */
	protected $uid;
	public function getUid() { return $this->uid; }
	public function setUid($uid) { $this->uid = $uid; return $this; }

	/**
	 * @Column(type="string")
	 * @var string
	 */
	protected $firstname;
	public function getFirstname() { return $this->firstname; }
	public function setFirstname($firstname) { $this->firstname = $firstname; return $this; }

	/**
	 * @Column(type="string")
	 * @var string
	 */
	protected $lastname;
	public function getLastname() { return $this->lastname; }
	public function setLastname($lastname) { $this->lastname = $lastname; return $this; }

	/**
	 * @Column(type="string", unique=true)
	 * @var string
	 */
	protected $email;
	public function getEmail() { return $this->email; }
	public function setEmail($email) { $this->email = $email; return $this; }
}

//The form class
//This should be placed in a separate file
//See http://symfony.com/doc/current/book/forms.html#creating-form-classes
class PersonForm extends SForm\AbstractType {
	public function buildForm(SForm\FormBuilder $builder, array $options) {
		$builder->add('id', null, array('read_only' => true));
		$builder->add('uid', null, array('read_only' => true));
		$builder->add('firstname');
		$builder->add('lastname');
		$builder->add('email');
	}

	public function getDefaultOptions(array $options) {
		return array(
			'data_class' => 'Standalone\Form\Person',
		);
	}

	public function getName() {
		return 'standalone';
	}
}

//Create a default DI container which will be used later
$container = new SDI\Container(new SDI\ParameterBag\ParameterBag());

//Here comes Doctrine init code (connection, event manager, entity manager, ...)
//Each component has to be put in the container (doctrine.connection, doctrine.entity_manager, ...)
//...

//Create a Doctrine Registry
$registry = new SBridge\Doctrine\Registry(
	$container,
	array('default' => 'doctrine.connection'),
	array('default' => 'doctrine.entity_manager'),
	'default',
	'default'
);

//And store it in the default container
$container->set('doctrine.registry', $registry);

//Create a default FormFactory
$factory = new SForm\FormFactory(array(
	new SForm\Extension\Core\CoreExtension(),
	new SBridge\Doctrine\Form\DoctrineOrmExtension(
		$container->get('doctrine.registry')
	)
));
//And store it in the default container
$container->set('form.factory', $factory);

//Create or retrieve an Person from database
//Store it in the $person variable
//And pass this variable as the second parameter (form data) of the FormFactory::create() method
$person = null;

//Create the form
$form = $container->get('form.factory')->create(
	new PersonForm(
		$container->get('doctrine.registry')
	),
	$person
);
?>