php闭包作为函数参数

<?php

function test(Closure $call)
{
    $a = 63;
    $b = 22;
    echo "hello";
   echo  $call($a,$b);
}
$func = function($a,$b){
    return $a + $b;
};

test($func);  //调用顺序 先调用test ，输出hello  然后$call是个闭包，执行这个函数，传递两个值过去，想加后返回 

[root@localhost swoole]# php time.php
hello85[root@localhost swoole]#