Slim framework — Как автоматически загружать Slim / Slim.php вместо использования require?

Как я могу автоматически загружать Slim / Slim.php вместо использования require?

// standard method
//require 'ext/Slim/Slim.php';

// autoload method:
define ('WEBSITE_DOCROOT', str_replace('\\', '/', dirname(__FILE__)).'/');

// Instance of SplAutoload.
$SplAutoload = new SplAutoload();

// Load classes.
$SplAutoload->fetch([
'ext/' // Slim/ is kept under ext/
]);

\Slim\Slim::registerAutoloader();

//Instantiate a Slim application:
$app = new \Slim\Slim();

//Define a HTTP GET route:
$app->get('/', function () {
echo "Hello!";
});

$app->get('/hello/:name/', function ($name) {
echo "Hello, $name";
});

//Run the Slim application:
$app->run();

Я получаю эту ошибку,

Неустранимая ошибка: класс ‘Slim \ Slim’ не найден в C: …

класс SplAutoload,

class SplAutoload
{
/**
* Set the property.
*/
public $directories;

public function fetch($directories)
{
// Store the data into the property.
$this->directories = $directories;

// Register the classes that were loaded by __autoload as well.
spl_autoload_register('__autoload');

// When using spl_autoload_register() with class methods, it might seem that it can use only public methods,
// though it can use private/protected methods as well, if registered from inside the class:
spl_autoload_register([$this,'getClass']);
}

private function getClass($className)
{
if(is_array($this->directories)): $mainDirectories =  $this->directories;
else: $mainDirectories =  array($this->directories); endif;

// Set other vars and arrays.
$subDirectories = [];
//print_r($mainDirectories);

$namespace = "\\";
$isNamespace = false;

// When you use namespace in a class, you get something like this when you auto load that class \foo\tidy.
// So use explode to split the string and then get the last item in the exloded array.
$parts = explode($namespace, $className);

// Check if the current class is a namespace class or not.
if(strpos($className, $namespace) !== false)
{
$isNamespace = true;
}

// Set the class file name.
$filename = end($parts).'.php';

// List any sub dirs in the main dirs above and store them in an array.
foreach($mainDirectories as $mainDirectory)
{
// Check if the directory exists.
// Create it if it doesn't.
if (!file_exists(WEBSITE_DOCROOT.$mainDirectory))
{
mkdir(WEBSITE_DOCROOT.$mainDirectory, 0777);
}

// Must use absolute path to get the files when ajax is used.
foreach(glob(WEBSITE_DOCROOT.$mainDirectory.'*', GLOB_ONLYDIR) as $dir)
{
// Must trim off the WEBSITE_DOCROOT.
$subDirectories[] = preg_replace('~.*?(?=core|local)~i', '', str_replace('\\', '/', $dir)) .'/';
}
}

// Mearge the main dirs with any sub dirs in them.
$mergedDirectories = array_merge($mainDirectories,$subDirectories);

// Loop the merge array and include the classes in them.
foreach($mergedDirectories as $mainDirectory)
{
if(file_exists(WEBSITE_DOCROOT.$mainDirectory.$filename))
{
include_once WEBSITE_DOCROOT.$mainDirectory.$filename;

// Check if the class has existed.
if($isNamespace === false) if (class_exists($className)) break;
}
}
}
}

или любой другой автозагрузчик SPL, на который я должен пойти? Зенд-автопогрузчик?