In Swift 3, what is a way to compare two closures?

Question

Suppose you have two closures of type (Int)->() in Swift 3 and test to see if they are the same as each other:

typealias Baz = (Int)->()
l         


        

Answer 1

In the case where you want to track your own closures, uses them as Dictionary keys, etc., you can use something like this:

struct TaggedClosure: Equatable, Hashable {
    let id: Int
    let closure: (P) -> R

    static func == (lhs: TaggedClosure, rhs: TaggedClosure) -> Bool {
        return lhs.id == rhs.id
    }

    var hashValue: Int { return id }
}

let a = TaggedClosure(id: 1) { print("foo") }
let b = TaggedClosure(id: 1) { print("foo") }
let c = TaggedClosure(id: 2) { print("bar") }

print("a == b:", a == b) // => true
print("a == c:", a == c) // => false
print("b == c:", b == c) // => false