Manolis Pahlke shakemno

Conventions

A = [xA, yA] is a point on the 2D plane. Same for B, C, ...
lengths are in any unit (ex: pixels)
code snippets are in JavaScript

Degrees to radians

angleRad = angleDeg * Math.PI / 180;

A composable pattern for pure state machines with effects

State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?

There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.

Here I present a composable pattern for pure state machiness with effects,

	# simple navigation componenent like on iOS
	# put at the top of your file

	class Paging

	pages = Array()

	constructor: (@bg_layer) ->

	# push a new page on top

	import UIKit
	import GenericViewKit

	public class StateView: GenericView {
	public enum State {
	case Loading
	case Loaded
	case Error
	}

	protocol State {}

	struct Transition<From: State, To: State> {
	let transition: () -> To
	}

	struct Machine<CurrentState: State> {

	var state: CurrentState

	//:
	//: UIView Animation Syntax Sugar
	//:
	//: Created by Andyy Hope on 18/08/2016.
	//: Twitter: @andyyhope
	//: Medium: Andyy Hope, https://medium.com/@AndyyHope

	import UIKit

	extension UIView {

	//
	// debounce-throttle.swift
	//
	// Created by Simon Ljungberg on 19/12/16.
	// License: MIT
	//

	import Foundation

	extension TimeInterval {

	import Foundation
	import UIKit
	import ReactiveSwift
	import Result

	extension UIViewController {

	typealias KeyboardStatusInfo = (height: CGFloat , duration: TimeInterval, animationOptions: UIViewAnimationOptions)

	var keyboardUpdatesSignal: Signal<KeyboardStatusInfo, NoError> {

	import AppKit
	import AVFoundation

	class MovieWriter: NSObject {
	func writeImagesAsMovie(_ allImages: [NSImage], videoPath: String, videoSize: CGSize, videoFPS: Int32) {
	// Create AVAssetWriter to write video
	guard let assetWriter = createAssetWriter(videoPath, size: videoSize) else {
	print("Error converting images to video: AVAssetWriter not created")
	return
	}