[swift-evolution] [Review] SE-0029 Remove implicit tuple splat behavior from function applications

[Jerome ALVES]

Hello,

I use this feature to make generic "weak target actions" like this :


func weakTarget<T, S: AnyObject>(target: S, action: S -> (T -> Void)) -> (T -> Void) {
    return { [weak target] (input: T) -> Void in
        guard let target = target else { return }
        return action(target)(input)
    }
}

class Target {
    init() {}
    func printHello(firstName: String, lastName: String) {
        print("Hello \(firstName) \(lastName) !")
    }
}

class Receiver {
    init() {}
    var printSomething: ((String, String) -> Void)? = nil
}

var aTarget: Target? = Target()
let aReceiver = Receiver()

aReceiver.printSomething = weakTarget(aTarget!, action: Target.sayHello)

aReceiver.printSomething?("Jérôme", "Alves") // => "Hello Jérôme Alves !"

a = nil

aReceiver.printSomething?("Jérôme", "Alves") // => aReceiver.printSomething still has a value, but it does nothing


As you can see, if you call weakFunc() with a func which has multiple arguments, the T generic will be a tuple and I guess this is thanks to this "implicit tuple splat" feature but I'm not sure.
So can someone enlighten me ? Will this code continue to work if this proposal is approved ?


> Le 5 févr. 2016 à 19:12, Joe Groff via swift-evolution <swift-evolution at swift.org> a écrit :
> 
> Hello Swift community,
> 
> The review of “Remove implicit tuple splat behavior from function applications” begins now and runs through February 9, 2016. The proposal is available here:
> 
> https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md <https://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md>
> 
> Reviews are an important part of the Swift evolution process. All reviews should be sent to the swift-evolution mailing list at
> 
> https://lists.swift.org/mailman/listinfo/swift-evolution <https://lists.swift.org/mailman/listinfo/swift-evolution>
> 
> or, if you would like to keep your feedback private, directly to the review manager. When replying, please try to keep the proposal link at the top of the message:
> 
> Proposal link:
> 
> http://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md <http://github.com/apple/swift-evolution/blob/master/proposals/0029-remove-implicit-tuple-splat.md>
> 
> Reply text
> 
> Other replies
> 
> What goes into a review?
> 
> The goal of the review process is to improve the proposal under review through constructive criticism and, eventually, determine the direction of Swift. When writing your review, here are some questions you might want to answer in your review:
> 
> 	• What is your evaluation of the proposal?
> 	• Is the problem being addressed significant enough to warrant a change to Swift?
> 	• Does this proposal fit well with the feel and direction of Swift?
> 	• If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?
> 	• How much effort did you put into your review? A glance, a quick reading, or an in-depth study?
> 
> More information about the Swift evolution process is available at
> 
> https://github.com/apple/swift-evolution/blob/master/process.md <https://github.com/apple/swift-evolution/blob/master/process.md>
> 
> Thank you,
> 
> -Joe
> Review Manager
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