capturing values

func doIncrement(data: Int) -> () -> Int{
    var total = 0
    func incrementer() -> Int // don't have paramenters but capturing value
    {
        total += data
        return total
    }
    return incrementer
}

var incrementByFive = doIncrement(data: 5)
print("incremented value is: ", incrementByFive())
print(incrementByFive())
print(incrementByFive())



// functions and closures are reference types
let alsoIncrementByFive = incrementByFive
print("still incremented by reference: ",alsoIncrementByFive())



// 

func printMessage(name: String, newClosure: () -> () ){
    print("hello")
    newClosure()
    print("function ended")
}
printMessage(name: "rohit",newClosure: { print("rohit") }) 



// @escaping closures
var completionHandlers: [() -> Void] = []
func completionHandlerEscaping(completionHandler: @escaping () -> Void){
    completionHandlers.append(completionHandler)
}



// autoclosure
// var customerLine = ["mr. gold", "luise", "anna", "ada"]

// func printCustomer(customer setClosur: () -> (String) ){
//     print("\nnow it's \(setClosur())'s turn")
// }
// printCustomer(customer: { customerLine.remove(at: 1) })
// print(customerLine.count) 



var customerLine = ["mr. gold", "luise", "anna", "ada"]
// The argument is automatically converted to a closure, because the setCustomer parameter’s type is marked with the @autoclosure attribute
func printCustomer(customer setCustomer: @autoclosure () -> (String) ){
    print("\nnow it's \(setCustomer())'s turn")
}
printCustomer(customer:  customerLine.remove(at: 1) )
print(customerLine.count) 

// Note
// Overusing autoclosures can make your code hard to understand. The context and function name should make it clear that evaluation is being deferred.