CODEWITHSUNDEEP
iosswiftxcode
spinhaxo
spinhaxo

Reputation: 58

iOS Swift function with type () -> ()

Im unable to create function of type () -> () in Swift with xCode...
so far im at 

func successBlock() -> Void {
    //code
    return ()
}

but this is only () not () -> ()
I want this function to fit the type () -> () because of this function:

func loginToFacebookWithSuccess(callingViewController: UIViewController, successBlock: () -> (), andFailure failureBlock: (NSError?) -> ()) {

gonna pass the successBlock() func as variable in there.
I have nearly the same problem with the failureBlock
or am I on the wrong way?

Thank you, spinhaxo

Upvotes: 1

Views: 111

Answers (3)

Thanh Pham
Thanh Pham

Reputation: 2090

If you decided to go with func, pass the function's name without the parentheses. Hence, pass successBlock instead of successBlock().

loginToFacebookWithSuccess(someViewController, successBlock: successBlock, andFailure: failureBlock)

That's because the type of the function successBlock is () -> () while its return type is only ().

Extra:

  1. () has an alias which is Void: public typealias Void = ().

You can even omit Void nor ():

func successBlock() {
  //code
  //no return statement needed
}

func failureBlock(error: NSError?) {
  //code
  //no return statement needed
}

Upvotes: 2

Viktor Simkó
Viktor Simkó

Reputation: 2637

successBlock is a function.
You need closures.

let successBlock: () -> () = {
  // do something here...
}

let failureBlock: (NSError?) -> () = { error in
  // do something with the error...
}

If you don't want to store them, you can just define them while calling the method like this:

loginToFacebookWithSuccess(
  callingController,
  successBlock: {
    // do something here...
  }, andFailure: { error in
    // do something with the error...
  }
)

Upvotes: 2

OOPer
OOPer

Reputation: 47886

Seems you are confusing a closure with the result of calling the closure.

You just need to pass successBlock, which is a closure of type () -> (). (aka () -> Void)

But successBlock() represents the result of calling successBlock, which may be a void value (aka ()), not a closure.

Nearly the same for failureBlock. Do not pass the result of calling closures, pass closures themselves.

Upvotes: 1

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