如何在PHP中的文本中评估（或回显）类变量

I know it is possible to echo variables directly in text

$apples = 4;
echo "You have $apples apples."

How do it with class variable? This doesn't work.

class service {
    public $active;
}
$service["test"] = new service();
$service["test"]->active = true;

echo "Test service is: $service[test]->active";

I ask because I need to print class variable in eval (I use MyBB engine for forum).

eval("\$site .= \"".$templates->get($template)."\";");

Previously I've used {$var} and it worked but {$var[sth]->sth} doesn't.

This works and there is no need for eval()

class service {
    public $active;
}
$service["test"] = new service();
$service["test"]->active = 99;

echo "Test service is: {$service['test']->active}";

Or

class service {
    public $active;
}
$service["test"] = new service();
$service["test"]->active = true;

echo "Test service is: " . $service['test']->active == true ? 'TRUE' : 'FALSE';