statefull_machine/autoload.php

<?php

/**
 * Simple PSR-4 autoloader
 * @param string $class Class name
 */
spl_autoload_register(function($class) {

    // Package namespace
    $prefix = 'Fr\\RetailMeNot\\Cloud\\StateMachine\\';

    // Source folder
    $src = dirname(__FILE__).'/src/';

    // Does the class use the namespace prefix ?
    $len = strlen($prefix);

    // If no, move to next autoloader ...
    if (strncmp($prefix, $class, $len) !== 0) {
        return;
    }

    // Get relative class name
    $relative = substr($class, $len);

    // Build class path
    $file = $src.str_replace('\\', DIRECTORY_SEPARATOR, $relative).'.php';

    // If the file exists, require once it
    if (file_exists($file)) {
        require_once $file;
    }

});