gistfile1.swift

//
// Copyright (c) Vatsal Manot
//

import Foundation
import Swift

public func type<T>(x: T) -> T
{
    return x
}

private var storage = NSUserDefaults.standardUserDefaults()

public struct Preferences
{
    public static var storage: NSUserDefaults
    {
        return NSUserDefaults.standardUserDefaults()
    }
}

extension Preferences
{
    public static func get(key: String) -> AnyObject?
    {
        return storage.objectForKey(key)
    }
    
    public static func get<T: AnyObject where T: NSCoding>(key: String, type: T.Type = type(T)) -> T?
    {
        return storage.objectForKey(key) as? T
    }
    
    public static func get<T: _ObjectiveCBridgeable where T._ObjectiveCType: NSCoding>(key: String, type: T.Type = type(T)) -> T?
    {
        return storage.objectForKey(key) as? T
    }
}

extension Preferences
{
    public static func set<T: AnyObject where T: NSCoding>(value: T, forKey key: String)
    {
        storage.setObject(value, forKey: key)
    }
    
    public static func set<T: _ObjectiveCBridgeable where T._ObjectiveCType: NSCoding>(value: T, forKey key: String)
    {
        storage.setObject(value as? T._ObjectiveCType, forKey: key)
    }
}

extension Preferences
{
    public static func remove(key: String)
    {
        storage.removeObjectForKey(key)
    }
}

extension Preferences
{
    public static func synchronize()
    {
        storage.synchronize()
    }
}

Preferences.set([NSData()], forKey: "MyKey1")
Preferences.get("MyKey1", type: type([NSData]))
Preferences.get("MyKey1") as [NSData]?

func crunch1(value: [NSData])
{
    println("Om nom 1!")
}

crunch1(Preferences.get("MyKey1")!)

Preferences.set(NSArray(object: NSData()), forKey: "MyKey2")
Preferences.get("MyKey2", type: type(NSArray))
Preferences.get("MyKey2") as NSArray?

func crunch2(value: NSArray)
{
    println("Om nom 2!")
}

crunch2(Preferences.get("MyKey2")!)

Preferences.set([[String:[Int]]](), forKey: "MyKey3")
Preferences.get("MyKey3", type: type([[String:[Int]]]))
Preferences.get("MyKey3") as [[String:[Int]]]?

func crunch3(value: [[String:[Int]]])
{
    println("Om nom 3!")
}

crunch3(Preferences.get("MyKey3")!)