Closure

加载中间件，注册回调事件。

参考Larveal中间件加载方式
具体代码如下：

define("MALE",1);
define("FEMALE",0);

$request = new stdClass();
$request->age = 9;
$request->sex = MALE;
$request->name = "小明";
$request->info = "牛逼的人";


//handle1，2,3,4是我要加入的注册事件,$request是原有请求
function handle1(Closure $next){
    return function($request)use($next){
        if($request->age<10){
            echo "年龄小于10岁，不许坐车。",PHP_EOL;
        }
        return $next($request);
    };
}
function handle2(Closure $next){
    return function($request)use($next){
        return $next($request);
    };
}
function handle3(Closure $next){
    return function($request)use($next){
        return $next($request);
    };
}
function handle4(Closure $next){
    return function($request)use($next){
        return $next($request);
    };
}

function lastClosure(){
    return function($request){
        var_dump($request);
    };
}

//$p2 = call_user_func("handle1",lastClosure());
//$p3 = call_user_func('handle2',$p2);
//$p4= call_user_func('handle3',$p3);
//$p5= call_user_func('handle4',$p4);
//call_user_func($p5,$request);
//die();

$newPipe = new Pipe();
Pipe::register("handle1");
Pipe::register("handle2");
Pipe::register("handle3");
Pipe::register("handle4");
$newPipe->run($request);

class Pipe{
    private static $pipes;
    public function __construct(){
        self::$pipes = array();
    }
    public static function register($handle){
        self::$pipes[] = $handle;
    }

    //相当于 lastClosure()
    public function getFirstClosure(){
        return function($request){
            var_dump($request);
        };
    }

    public function getClosure(){
        return function($closure,$pipe){
            return function($request)use($closure,$pipe){
                call_user_func(call_user_func($pipe,$closure),$request);
            };
        };
    }

    public function run($request){
        $firstClosure = $this->getFirstClosure();
        /**
         * 解释一下：
         * array_reduce(self::$pipes,$this->getClosure(),$firstClosure) 中间这个$this->getClosure()肯定是一个双重的closure.调用之后返回的还是一个Closure.
         */
        call_user_func(array_reduce(self::$pipes,$this->getClosure(),$firstClosure),$request);
    }

}