PreferredOptionalChecks

import Cocoa


class StringHolder {
    var a : String?
    var b : String?
    var c : String?
    
    func naiveDescription() -> String {
        return a! + b! + c!
    }
    
    func preferredDescription() -> String {
        var builtString : String = ""
        if let defA = a? {
            builtString += defA
        }
        if let defB = b? {
            builtString += defB
        }
        if let defC = c? {
            builtString += defC
        }
        return builtString
    }
}

var holder = StringHolder()
holder.a = "a String "
holder.b = "b string"
println(holder.preferredDescription()) // successfully prints the description
println(holder.naiveDescription())  // since c is not set and it is forced, this crashes

Something like this would be a bit more general:

func preferredDescription() -> String {
    let strings = [a, b, c]
    return strings.map({ $0 ? $0! : "" }).reduce("", combine: +)
}

@joshaber yes that is concise. I'll take it. Thank you for that.

Awww, @joshaber looks like they broke this in the latest. wah waaaahhh. I'll play around

Looks like it may just be the implicit comparison to nil. Got it.