[swift-evolution] Spread Operator as Shorthand for Map

Sean Kosanovich sean7512 at me.com
Wed Dec 16 06:47:35 CST 2015

As a Groovy user, I really enjoy the shorthand Spread Operator over the Collect Closure (Map is the equivalent in Swift).

Consider the following Swift code:

struct Car {
    let make: String
    let model: String

let cars = [Car(make: "Jeep", model: "Grand Cherokee"), Car(make: "Dodge", model: "Challenger")]
let makes = cars.map() { $0.make }


Now consider the same code using a Spread Operator:

let makes = cars*.make

The other distinction in Groovy is that the Spread Operator is null safe, meaning it won’t throw a NPE if an element is null, whereas the Collect Closure would.  So in Swift, I would propose the Spread Operator implicitly does this when operating on an array of Optionals:

let makes = cars.map() { $0?.make }

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