function  cl($name){
       return sprintf('hello %s',$name);
  }

echo cl('world');

  $cl = function($name){
    return sprintf('hello %s',$name);
  };
  echo $cl('world');

object(Closure)#1 (1) {
  ["parameter"]=>
  array(1) {
    ["$name"]=>
    string(10) ""
  }
}

echo preg_replace_callback('~-([a-z])~', function ($match) {
  return strtoupper($match[1]);
}, 'hello-world');

$message = 'hello';
$example = function() use ($message){
  var_dump($message);
};
echo $example();

$message = 'hello';
$example = function ($data) use ($message){
  return "{$data},{$message}";
};

echo $example('world');

$message = 'hello';
$test = function () use ($message){
 var_dump($message);
 $message = 'Hi……';
};
$test();   

$message = 'Ni Hao！';
$test(); 

string(5) "hello"
string(5) "hello"