将变量传递给匿名函数而不使用use关键字

Question

I have a Router class:

$router->
    get($pattern, $callback); // creates a new route
    [...]

And an Application class:

$app->
    get($pattern, $callback); // calls the router `get()` method
    [...]

The problem is, when I'm setting the callback, inside each function I need the $app instance. I know I can use the use keyword, but using it for every route, every callback will by annoying and pointless.

Example:

Change:

$app->get('here/is/my/pattern', function () use ($app) {
    $app->controller('just_an_example');
});

To:

$app->get('here/is/my/pattern', function () {
    $app->controller('just_an_example');
});

How can I pass a variable to an anonymous function without the use keyword?

Answer 1

Your design is wrong.

It is not the Router's job to call the Controller. Instead, your Router should return something (usually a Route object) the corresponds to the match route. Generally like so:

$router = new Router($reuqest->getURI()); //The request URI
$router->addRoute("some/pattern", "SomeController");
$router->addRoute("some/other/pattern", "SomeOtherController");
$route = $router->route(); //$route now has a Route object.

$controllerClass = $route->getResource();
$app->$controllerClass($request); //Pass the Request object with GET and POST and whatever into the controller

This way, the router doesn't know it goes to some controller, and the controller doesn't know it came from a route. The two components are now completely reusable.