Swift syntax - closures

Question

I am a bit struggling to construct a call in SWIFT for this function

func addressFromLocation(location:CLLocation!, completionClosure:((NSDictionary?)->())){

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), { () -> Void in
        var geoCoder = CLGeocoder()
        geoCoder.reverseGeocodeLocation(location, completionHandler: { (placeMarks, error) -> Void in
            if let places = placeMarks {
                var marks = places[0] as! CLPlacemark
                completionClosure(marks.addressDictionary)
            }else {
                completionClosure(nil)
            }

        })
    })
}

Can anybody help?

can you give some more explanation on what you're trying to construct.? — arthankamal, Sep 28 '15 at 09:34
@arthankamal I wanna call that function, so to construct a call according to SWIFT syntax which I am not sure how to do. — Vanya, Sep 28 '15 at 09:38
http://stackoverflow.com/a/27750189/1866077, hope this helps — arthankamal, Sep 28 '15 at 09:43
@arthankamal thanx, but I am wondering how to call this function with this specific closure. — Vanya, Sep 28 '15 at 09:48
call you function with `addressFromLocation(location, completionClosure: { yourDict in // your code })` — arthankamal, Sep 28 '15 at 09:52

score 0 · Accepted Answer · answered Sep 28 '15 at 09:49

First, you can remove unnecessary parentheses from completionClosure parameter type:

func addressFromLocation(location: CLLocation!, completionClosure: NSDictionary? -> ()){
    //...
}

And you can call this function like so:

addressFromLocation(location, completionClosure: {
    dict in
    // your code
})

Or even simpler because if closure is final argument of function then you can use trailing closure syntax:

addressFromLocation(location) {
    dict in
    // your code
}

And if you are do not need named parameter dict then you can refer parameter by number:

addressFromLocation(location) {
    print($0)
}

Yes, you're right with those parentheses. And thank you, works fine. — Vanya, Sep 28 '15 at 10:01

Swift syntax - closures

1 Answers1