Quando vou compilar recebo o seguinte erro:

"libc++abi.dylib: terminating with uncaught exception of type NSException"

e o debug navigator, na parte de Thread1, me destaca a seguinte parte do AppDelegate.swift:

"class AppDelegate: UIResponder, UIApplicationDelegate{ "

Não sei o que está errado.

Meu código é:

Item.swift:

class Item {
    let name:String
    let calories:Double
    init (name:String, calories:Double) {
        self.calories = calories
        self.name = name
    }


}

Meal.swift:

class Meal {
    let name:String
    let happiness:Int
    var Items:Array<Item> = []
    init (name: String, happiness:Int) {
        self.name = name
        self.happiness = happiness
    }

    func allCalories() -> Double{
        var total:Double = 0
        for i in Items {
            total += i.calories
        }

        return total
    }

}

e o ViewControler.swift:

import UIKit

class ViewController: UIViewController {


    @IBOutlet var nameField: UITextField?
    @IBOutlet var happinessField: UITextField?

    @IBAction func add() {
        if nameField == nil || happinessField == nil {
            return
        }
        let name = nameField!.text
        let happiness = happinessField!.text.toInt()
        if happiness == nil {
            return
        }
        let meal = Meal(name: name, happiness: happiness!)
        println("eaten: \(meal.name) \(meal.happiness)")
    }


}

Não sei o que pode estar dando errado. Não consigo ir para frente