singletonize.php

<?php
function singletonize(\Closure $func)
{
    $singled = new class($func)
    {
        // Hold the class instance.
        private static $instance = null;
        public function __construct($func = null)
        {
            if (self::$instance === null) {
                self::$instance = $func();
            }
            return self::$instance;
        }
        // The singleton decorates the class returned by the closure
        public function __call($method, $args)
        {
            return call_user_func_array([self::$instance, $method], $args);
        }
        private function __clone(){}
        private function __wakeup(){}
    };
    return $singled;
}