why does swift closure complain there is no init - TagMerge
3why does swift closure complain there is no initwhy does swift closure complain there is no init

why does swift closure complain there is no init

Asked 5 months ago
3 answers

The issue there is that the closure expects two parameters:

var handler: (String, (Bool) -> Void) -> Void = { _,_  in }

handler = { a, b in

handler("a") { bool in print(bool) }

This will print:


Source: link


The following is a very clear and clean syntax for closures:
{(parameters) -> return type      in     statements}
Assign closures to variables or constants
let a = {(b:Int) -> Int    in    return b * 5}
Closures in an array or other collection types
let closures = [    {(a: Int) -> Int in return a * 3}]
Proceed to closure with a number of closures that all take an integer as a parameter and return an integer. We don’t need to rewrite it because Swift can infer the types of the parameters and values it returns.
let closures = [    {(x:Int) -> Int in return x * 7},    {x in return x - 2},    {$0 * 4}]
A closure can catch constants and variables specified in the body, as well as change their value. Since functions and closures are the same thing, nested functions are just another type of closure.
func counterMaker(number: Int) -> Int {    var total = 0    //function within function    func addNumber() -> Int {        total += number        return total    }    return addNumber}

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To put it in simple words: a closure is a block of code that you can assign to a variable.
let someVariable = 10let someCoolerVariable = {    return 10}()
I know, I know that’s a really messed up way to declare a variable! Let’s move on. I bet you must have seen the declaration below:
func pretendItsACoolName() {      // Some really complex logic here}
You can define a closure like this :
let myNickname: (String) -> String = { (name: String) in   return "I am Shubham Bakshi a.k.a. \(name)"}myNickname("Boxy") // I am Shubham Bakshi a.k.a. Boxy
Let’s first move our closure type into a typealias as it’s really good practice to use typealias in your code as it improves readability and reusability.
typealias closureType = (String) -> String
So our code now will look like this :
typealias closureType = (String) -> Stringlet myNickname: closureType = {     return “I am Shubham Bakshi a.k.a. \($0)”}myNickname(“Boxy”)

Source: link

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