Symfony yaml config:执行纯php代码

# config.yaml
parameters:
    my_php_code: 'echo "Hello, World!";'

# SomeController.php
public function indexAction()
{
    $phpCode = $this->getParameter('my_php_code');
    eval($phpCode);
}

# services.yaml
services:
    my_service:
        class: App\Service\MyService
        arguments:
            - 'echo "Hello, World!";'

# MyService.php
namespace App\Service;

class MyService
{
    public function __construct($phpCode)
    {
        eval($phpCode);
    }
}

# services.yaml
services:
    my_event_listener:
        class: App\EventListener\MyEventListener
        tags:
            - { name: kernel.event_listener, event: kernel.request }

# MyEventListener.php
namespace App\EventListener;

use Symfony\Component\HttpKernel\Event\RequestEvent;

class MyEventListener
{
    public function onKernelRequest(RequestEvent $event)
    {
        $phpCode = 'echo "Hello, World!";';
        eval($phpCode);
    }
}