PHP classes cannot be loaded unless namescape is included or commented out

Question

After searching through the site, I'm at a loss as to why I'm getting a fatal error about my class not being found unless I either instantiate the class with the namescape prefixing it, or comment out the namescape in the class file. I'm using PSR-0 to try and resolve this issue with no luck, along with this thread here, which was the closest to my issue.

Autoloader code:

    function autoload($className)
{
    $className = ltrim($className, '\\');
    $fileName  = '';
    $namespace = '';
    if ($lastNsPos = strrpos($className, '\\')) {
        $namespace = substr($className, 0, $lastNsPos);
        $className = substr($className, $lastNsPos + 1);
        $fileName  = str_replace('\\', DIRECTORY_SEPARATOR, $namespace) . DIRECTORY_SEPARATOR;
    }
    $fileName .= str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';

    require $fileName;
}

spl_autoload_register('autoload');

Path for all three files (Autoloader.php, Class.php, index.php) are all on the same directory level. No subdirectories or anything like that.

Autoloader code is implemented at the beginning of index.php with a require_once("Autoloader.php");

Classes are called at $foo = new classFoo();

tl;dr version:

• Commenting out namescape declaration in class being called? Works fine.
• Instantiating class using namescape/class formatting? Works fine.
• Otherwise? Fatal error: Class not found (even though it's in the same directory.

Answer 1

If you are in the global namespace, and the classes are in some other namespace, then even if the files are required by autoloader or manually, you still need to use the namespace when declaring the class. That is the point of namespacing, to prevent class name collisions.

It looks like you may be mixing PSR-0 and PSR-4 since you have namespaced classes but they aren't pathed properly \<NamespaceName>(\<SubNamespaceNames>)*\<ClassName>.