Twig错误：警告：{closure}（）缺少参数1

I'm coding an app in PHP for school work and I'm using Twig template engine lonely (without a framework).

I got a file which initialize Twig in my project and I use it in all files that need it.

include_once('./Twig/lib/Twig/Autoloader.php'); 
Twig_Autoloader::register();
$loader = new Twig_Loader_Filesystem('./templates');    
$twig = new Twig_Environment($loader, array(
    'cache' => false,
    'charset' => 'utf-8'
));

I have a Twig Function which returns the path to my static files folder. But when I run addFunction($my_function) I got the error below :

Warning: Missing argument 1 for {closure}()

My Twig function:

$url_for_static = new Twig_SimpleFunction('static_folder', function () {
$static_folder = "./static" ;
    return $static_folder ;
});

$twig->addFunction($url_for_static);

I know this answer is really late but i finally found a solution to my problem. My Twig function declaration was wrong. This worked for me :

`

function blank_space($size=100) {       
    echo "<div class='grid-". $size ." hidden'> <span> hidden </span> </div>" ;
}
$twig->addFunction('blank_space', new Twig_Function_Function('blank_space')) ;

`

I have never used Twig before, but it seems the closure is called with an argument but you didn't define any arguments in your closure. Try this:

$url_for_static = new Twig_SimpleFunction('static_folder', function ($arg) {
    var_dump($arg);
    $static_folder = "./static" ;
    return $static_folder ;
});

I know this answer is really late but i finally found a solution to my problem. My Twig function declaration was wrong.

This worked for me :

function blank_space($size=100) { 
    echo "<div class='grid-". $size ." hidden'> <span> hidden </span> </div>" ; 
} 

$twig->addFunction('blank_space', new Twig_Function_Function('blank_space')) ;