garybernhardt

This document has moved!

It's now here, in The Programmer's Compendium. The content is the same as before, but being part of the compendium means that it's actively maintained.

ashfurrow

Apps to install from macOS App Store:

• Pastebot
• GIF Brewery
• Slack
• Keynote/Pages/Numbers
• 1Password
• OmniFocus 3
• Airmail 3
• iA Writer

andymatuschak

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,

emotality

NOTE (2022-07-09): Xcode finally added this functionality in Xcode 14, please see release notes here:

New Features in Xcode 14 Beta 3
When editing code, the Edit > Duplicate menu item and its corresponding keyboard shortcut now duplicate the selected text — or the line that currently contains the insertion point, if no text is selected. (8614499) (FB5618491)

---

Xcode line duplicate

Bind keys to duplicate lines in Xcode

irace

import Foundation

/**
 Coordinators are a design pattern that encourages decoupling view controllers such that they know as little as possible 
 about how they are presented, and don’t directly manipulate data or present other view controllers. Coordinators can be 
 “nested” such that child coordinators encapsulate different flows and present any from becoming too large.
 
 - https://vimeo.com/144116310
 - http://khanlou.com/2015/10/coordinators-redux/
 - http://khanlou.com/2015/01/the-coordinator/

AliSoftware

struct Coordinator {
  let window: UIWindow
  let navCtrl: UINavigationController?
  
  func start() {
    presentWelcomeScreen()
  }
  
  private func presentWelcomeScreen() {
    let vc = WelcomeScreenViewController() // Instanciate from code, XIB, Storyboard, whatever your jam is

dsherret

// NOTE: This is now rolled up in a package and supports more scenarios: https://github.com/dsherret/using-statement

interface IDisposable {
    dispose();
}

function using<T extends IDisposable>(resource: T, func: (resource: T) => void) {
    try {
        func(resource);
    } finally {

pyrtsa

import Random

random(0 ..< 10)               // Int
random(1 ... 1000_000)         // Int
random(-1000_000 ... 1000_000) // Int
random(Int.min ... Int.max)    // Int

randomMax(UInt64.max)          // UInt64
random(0 ... UInt64.max)       // UInt64
random(1 ... UInt(10))         // UInt

mattt

import Darwin

extension Int {
    static func random() -> Int {
        return Int(arc4random())
    }

    static func random(range: Range<Int>) -> Int {
        return Int(arc4random_uniform(UInt32(range.endIndex - range.startIndex))) + range.startIndex
    }

nyg

// Thanks to http://www.labs.saachitech.com/2012/10/23/pdf-generation-using-uiprintpagerenderer
// Note: including images in the HTML won't work, see here:
// https://github.com/nyg/HTMLWithImagesToPDF

import UIKit

// 1. Create a print formatter

let html = "<b>Hello <i>World!</i></b>"
let fmt = UIMarkupTextPrintFormatter(markupText: html)