在闭包中使用父函数参数

Question

I'm trying to use a parameter that is passed through to resource controller action in Laravel 4 in a closure that is filtering a model collection, however I get the error below:

Undefined variable: slug

How can I pass through the $slug parameter from the route through to the collection filter closure?

public function show($slug)
{
    return Auth::user()->sessions->filter(function($session)
    {
        return $session->slug == $slug;
    });
}

All I am trying to achieve is to return the session of the user that matches the given slug. I've tried something like this to no avail:

Auth::user()->sessions->whereSlug($slug);

Answer 1

Try a use() clause:

return Auth::user()->sessions->filter(function($session) use( $slug)
{
    return $session->slug == $slug;
});