What is an autoclosure?

• The @autoclosure attribute is used to tell the compiler that it should wrap an argument in a closure expression.
• Basically we annotate a function parameter with @autoclosure.
• Instead of passing a closure as a parameter to a function, if the parameter is annotated with @autoclosure it can be passed as if it is a String.

Without autoclosure

• We have to wrap the code we want to call in { } at the call site.

// penaltyTakers ["Scott Brown", "James Forrest", "Kieran Tierney"]

func takePenalty(player penaltyTaker: () -> String) {
    print("Penalty taker \(penaltyTaker())!")
}

takePenalty(player: { penaltyTakers.remove(at: 0) } )

// Prints "Penalty taker Scott Brown!"

With autoclosure

• Adding @autoclosure in front of the closure parameter type.
• No need for { } at the call site.

// penaltyTakers ["Scott Brown", "James Forrest", "Kieran Tierney"]

func takePenalty(player penaltyTaker: @autoclosure () -> String) {
    print("Penalty taker \(penaltyTaker())!")
}

takePenalty(player: penaltyTakers.remove(at: 0) )

// Prints "Penalty taker Scott Brown!"

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