This document summarizes new features in Swift 2 including guard/defer statements for flow control, protocol extensions for default implementations, and error handling improvements like throwing and catching errors. It also mentions Swift becoming open source with its source code released under a permissive license and contributions accepted from the community, including ports for Linux. Nest is provided as an example open source Swift web framework project on GitHub.

1. A short introduction to
Swift 2

2. syntax goodies

3. Swift 1.2
- Objective-C generics
- Pattern Matching
- Availability Checking
- do/while is now repeat
- unit testing via @testable
- Markdown support for documentation
(including images)

4. nested generic value types
public enum Result<T> {
case Success(T)
case Error(NSError)
}
public enum Result<T> {
case Success(Box<T>)
case Error(NSError)
}
Swift 1.2
Swift 2

5. guard
func someFunction(value: Int?){
guard let value = value else {return}
let calc = 1 + value
}

6. defer
func awesomeStuff() {
someCalculation()
defer { cleanUp() }
otherStuff()
}

7. available
if #available(iOS 8.0, *) {
// new features from iOS 8
} else {
// a fallback feature
}

8. error handling

9. calling a throwing function
do {
try otherStuff()
} catch let error {
// handle the error
}

10. throw an error
func otherStuff() throws {
throw NSError(domain: "OutOfIdeasException",
code: 404, userInfo: nil)
}

11. throw a custom error
enum Error: ErrorType {
case NetworkFailed
case DeviceOverheated
}
func otherStuff() throws {
throw Error.NetworkFailed
}
func awesomeStuff() {
do {
try otherStuff()
} catch Error.NetworkFailed {
// handle the error
} catch {
// unspecific error
}
}

12. force try
enum Error: ErrorType {
case NetworkFailed
case DeviceOverheated
}
func otherStuff() throws {
throw Error.NetworkFailed
}
func awesomeStuff() {
try! otherStuff()
}

13. protocol extensions

14. default implementations
protocol Drinkable {
func drink()
}
struct Beer: Drinkable {
}
struct Mate: Drinkable {
func drink() {
print("Mate specific drinking.")
}
}
extension Drinkable {
func drink() {
print("Time to drink!")
}
}
Beer().drink()

15. protocol oriented
programming
https://developer.apple.com/videos/wwdc/2015/?id=408

16. but there is
one more thing

17. Swift becoming
open source

18. • Swift source code will be released under an OSI-approved permissive
license.
• Contributions from the community will be accepted — and
encouraged.
• At launch we intend to contribute ports for OS X, iOS, and Linux.
• Source code will include the Swift compiler and standard library.

19. Nest
https://github.com/nestproject

20. https://github.com/nestproject/NestBox
import NestBox
let server = serve("127.0.0.1", 8080) { environ in
return ("200 OK", [], "Hello World!")
}
server()
Nest

21. Thank you.
@JensRavens
github.com/jensravens