hipster oriented programming

Jens Ravens

Developer at nerdgeschoss iOS/ OS X (Swift) Server / Backend (Ruby)

@JensRavens jensravens.de

nerdgeschoss.de

I hate monads already. Even if it’s the most useful, elegant thing - it’s all what’s wrong about hype based hipster-programming in one word.

- tweet after UIKonf

Is it really functional programming if you don't give a talk about it?

- @alejandrocrosa

This talk is not about functional programming.

What is a hipster anyway?

a person who follows the latest trends and fashions, especially those regarded as being outside the cultural mainstream.

- Wikipedia

orientation

Imperative

Do this 5 times!

func nullToNil(dict: [String: AnyObject])->[String: AnyObject]{ var cleaned = [String: AnyObject]() for (key, value) in dict { if !(value is NSNull) { cleaned[key] = value } } return cleaned }

Functional

Same input, same output.

let l = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] let sum = l.reduce(+) // 55

Object Oriented

Put your family of objects in a room and let them talk.

Protocol Oriented

You have a lot of equatable, comparable, parseable, archiveable, transmittable, displayable objects.

Spaghetti Oriented

JSON parsing.

What is state anyway?

class ViewController: UIViewController, UITableViewDelegate { var selectedItem: Item? func updateView() { // do something to update the display } func tableView(tableView: UITableView,

didSelectRowAtIndexPath indexPath: NSIndexPath) { selectedItem = findItemAtIndex(indexPath) } }

Question State How to recognise?

IP imperative

How? a lot of nested loops and assignments

OOP object oriented

How? (but encapsulated)

encapsulated state

seperation of concerns “unix principle”

POP protocol oriented

What? encapsulated objects implementing hundreds of protocols.

FP functional

What? no state. you have no idea what it’s doing, but it’s short and beautiful.

FRP functional reactive

When? over my dead lambda. you’re constantly flatMapping

They all mix pretty well.

- pretty big secret

bridging the worlds

Monads.http://fuckingmonads.com

Signals.jensravens.de/series/functional-reactive-programming-in-swift/

Boxing and Optionals.

Throwing Errors.

Mapping Arrays and Collections.

Type Safety.

Protocols and Facades.

combining ideas

idea 1

treating your user as an interface

user interface

RecipeRecipe

RecipeRecipe

Recipe

protocol User { func selectRecipe(recipies: [Recipe], completion:Recipe->Void) }

user interface

RecipeRecipe

RecipeRecipe

Recipe

protocol User { func selectRecipe(recipies: [Recipe], completion:Recipe?->Void) }

user interface

RecipeRecipe

RecipeRecipe

Recipe

protocol User { func selectSingle(collection: [Selectable], completion:Selectable?->Void) }

user interface

RecipeRecipe

RecipeRecipe

Recipe

func downloadStuff(term: String, completion: Result<[Recipe]>->Void){ // networking and error handling }

class UserSelection: UIViewController, User { static func selectRecipe(presentingViewController: UIViewController) (recipies: [Recipe], completion: Result<Recipe> -> Void) { // present your view controller here and save the completion block } }

let searchVC = // your current vc let textField = // the textfield used for typing textField .textSignal .flatMap(downloadStuff) .flatMap(UserSelection.selectRecipe(searchVC)) .next { recipe in // do whatever you like } .error { error in // something went wrong on the way }

idea 2

facades via typedef

abstract servers

public typealias Headers = [String: String] public typealias Environment = [String: AnyObject] public typealias StatusCode = Int public typealias Response = (StatusCode, Headers, ContentStreamable)

public typealias Swagable = Request throws -> Response

let HelloWorld: Swagable = { env in return (200, [:], "Hello World") }

idea 3

common behavior in protocols

protocol Contextable { func showContext(gestureRecognizer: UIGestureRecognizer) func viewControllerForContext(context: Item) -> UIViewController? func contextViewControllerForContext(context: Item) -> UIViewController? func contextForGestureRecognizer(gestureRecognizer: UIGestureRecognizer) -> Item? // the only required method func contextForIndexPath(indexPath: NSIndexPath) -> Item? }

extension Contextable { func viewControllerForContext(context: Item) -> UIViewController? { return self as? UIViewController } func contextForGestureRecognizer(gestureRecognizer: UIGestureRecognizer) -> Item? {

// find the clicked indexpath } }

extension ChannelViewController: Contextable { @IBAction func triggerContext(gestureRecognizer: UIGestureRecognizer) { showContext(gestureRecognizer) } func contextForIndexPath(indexPath: NSIndexPath) -> Item? { return dataSource.itemForIndexPath(indexPath) } }

These are just concepts.They won’t hurt you, they won’t take away your job.

It’s more out there than just object oriented programming.

object oriented programming has a lot of hidden gems you might not be aware of yet.

learning from other plattforms

these are amazing times to be a developer

do not just read about your plattform

What’s .next()?

Functors, Applicatives and Monads in Pictures.

http://adit.io/posts/2013-04-17-functors,_applicatives,_and_monads_in_pictures.html

The Introduction to RP you’ve been missing.

https://gist.github.com/staltz/868e7e9bc2a7b8c1f754

Imperative Programming In Swift (Graham Lee)

sicpers.info/2015/07/imperative-programming-in-swift/

Protocol-Oriented Programming in Objective-Csicpers.info/2015/06/protocol-oriented-programming-in-objective-c/

Mutable objects in immutable objects in object-oriented programming in functional programming in Swiftsicpers.info/2015/06/mutable-objects-in-immutable-objects-in-object-oriented-programming-in-functional-programming-in-swift/

keep searching for new frontiers

use the right tool for the right job

Thank you.

@JensRavensjensravens.de