php7_5.php

<?php
/**
 * 支持通过new 来创建一个匿名类，可以用来代替用后即焚的完整类定义
 */


interface Logger {
    public function log(string $msg);
}

class Application {
    private $logger;

    public function getLogger() : Logger
    {
        return $this->logger;
    }

    /**
     * @param mixed $logger
     */
    public function setLogger($logger): void
    {
        $this->logger = $logger;
    }
}

$app = new Application();
$app->setLogger(new class implements Logger{
    public function log(string $msg)
    {
        print_r($msg);
    }
});

$app->getLogger()->log('用new创建匿名类');