Accessing an 'outer' class property within a class that was invoked in a callback in PHP

Question

Apologies for the title, I wasn't sure of the best way to phrase this.

Essentially I'm trying replicate the absolute basics of Laravel's routing in a small personal application.

Below is the API I'm aiming for, however, I'm not sure how to access the namespace (api/v1) that's defined in the original Route::namespace call.

Route::namespace('api/v1')->group(function() {
    Route::get('/posts/{id}', [PostController::class, 'show']);
    Route::post('/posts', [PostController::class, 'store']);
});

So within the Route::get and Route::post methods, I need to somehow access that namespace value that was set via the outer call to Route::namespace. So Route::post('/posts') will end up registering an endpoint with the URI api/v1/posts.

Any pointers or guidance would much appreciated, Thanks.

---

Also here's the basic relevant parts of the Route class for reference.

class Route {
    public function __construct(public string $namespace = '', private string $uri = '', private mixed $handle = null, private string $type = '')
    {
        return $this;
    }

    public static function namespace(string $namespace): Route
    {
        return new Route(namespace: $namespace);
    }

    public function group(Closure $callback): self
    {
        $callback($this);

        return $this;
    }

    public static function get(string $uri, mixed $handle): Route
    {
        return new Route(uri: $uri, handle: $handle, type: 'get');
    }

    public static function post(string $uri, mixed $handle): Route
    {
        return new Route(uri: $uri, handle: $handle, type: 'post');
    }
}