获取PHP函数(Symfony 4.2)

use Symfony\Component\VarDumper\VarDumper;
use Symfony\Component\VarDumper\Cloner\VarCloner;
use Symfony\Component\VarDumper\Dumper\HtmlDumper;

$reflectionFunction = new \ReflectionFunction('functionName');

$parameters = $reflectionFunction->getParameters();

$returnType = $reflectionFunction->getReturnType();

$docComment = $reflectionFunction->getDocComment();

$cloner = new VarCloner();
$dumper = new HtmlDumper();

VarDumper::setHandler(function ($var) use ($cloner, $dumper) {
    $dumper->dump($cloner->cloneVar($var));
});

VarDumper::dump($reflectionFunction);