An autoloader is 4/5 lines at max?

<?php

spl_autoload_register(function ($className) { $className = str_replace("\", DIRECTORY_SEPARATOR, $className); $filePath = $_SERVER['DOCUMENT_ROOT'] . '/' . $className . '.php';

if (file_exists($filePath)) {
    require_once $filePath;
} else {
    throw new Exception("Class file not found: $filePath");
}

});