Unwrapping Multiple Swift Optionals

gistfile1.swift

// NOTE: @schwa figured this out, but I'm claiming some of the credit for asking the question.
// See https://gist.github.com/schwa/ecd5f8c154e60fcb0f58 for the original solution.

// Playground - noun: a place where people can play

import Foundation

// Implementation (repeat as needed for number of parameters).

func unwrap<T1, T2>(p1: T1?, p2: T2?) -> (T1, T2)? {
    // return p1 && p2 ? (p1!, p2!) : nil
    if p1 && p2 {
        return (p1!, p2!)
    }
    return nil
}

func unwrap<T1, T2, T3>(p1: T1?, p2: T2?, p3: T3?) -> (T1, T2, T3)? {
    // return p1 && p2 && p3 ? (p1!, p2!, p3!) : nil
    if p1 && p2 && p3 {
        return (p1!, p2!, p3!)
    }
    return nil
}

// Example

var a: String? = "A"
var b: String? = "B"
var c: String? = "C"

// New hotness
if let (x, y, z) = unwrap(a, b, c) {
    x
    y
    z
} else {
    "There was at least one nil"
}

// Old and busted
if a && b && c {
    let (x, y, z) = (a!, b!, c!)
    x
    y
    z
} else {
    "There was at least on nil"
}