app/Core/Router.php // We assume ROOT is defined externally if (!defined('ROOT')) { return; } $prefix = 'App\\'; $base_dir = ROOT . '/app/'; $len = strlen($prefix); if (strncmp($prefix, $class, $len) !== 0) { return; } $relative_class = substr($class, $len); $file = $base_dir . str_replace('\\', '/', $relative_class) . '.php'; if (file_exists($file)) { require_once $file; } }); } }