| 
<?php spl_autoload_extensions(".php");
 spl_autoload_register('system_autoloader');
 function system_autoloader($class)
 {
 $prefix = 'Facebook\\';
 // base directory for the namespace prefix
 // does the class use the namespace prefix?
 $len = strlen($prefix);
 if (strncmp($prefix, $class, $len) !== 0) {
 // no, move to the next registered autoloader
 return;
 }
 // get the relative class name
 $relative_class = substr($class, $len);
 
 // replace the namespace prefix with the base directory, replace namespace
 // separators with directory separators in the relative class name, append
 // with .php
 $file = APP_PATH."Facebook".APP_DS . str_replace('\\', '/', $relative_class) . '.php';
 
 // if the file exists, require it
 if (file_exists($file)) {
 require $file;
 }
 }
 
 |