A very quick PSR-0 SPL autoloader function

autoloadPSR0.php

<?php
//set_include_path(get_include_path() . PATH_SEPARATOR . __DIR__); // optional
spl_autoload_register(function ($class) {
    
    $file = preg_replace('#\\\|_(?!.+\\\)#','/', $class) . '.php';
    
    if (stream_resolve_include_path($file)) {
        
        require $file;
    }
});