k0nserv

On July the 7th I went to the CocoaHeads Stockholm meetup as I always try to do when they host one. For this particular meetup the brilliant, but unknown to me at the time, Orta Therox held a talk about open source, CocoaPods and how they work at Artsy. For very long time beforehand I had felt that I was not contributing back enough to all the awesome projects that I used daily, CocoaPods being one of them. Orta really inspired me to take the first steps to contribute back. I promptly went home and started working on a issue I found among the CocoaPods issues on GitHub. After finishing that one I jumped on to another one which was related. After a landing a few PRs Orta invited me to the CocoaPods slack team. It was during a discussion there that the questions for this blog post came up.

The question

In the mentioned the discussion the original questions was:

Why do Github issues

k0nserv

// The DoUntil struct holds the action that is
// the loop body
struct DoUntil {
  let action: () -> ()

  init(action: () -> ()) {
    self.action = action
  }
  
  // Using a method like this allows replacing what would have

k0nserv

func onMainThread(action: () -> ()) {
  dispatch_async(dispatch_get_main_queue(), action)
}

onMainThread {
  myView.hidden = true
}

func inBackground(action: () -> ()) {
  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), action)

k0nserv

// Perform some action 50% of the time
func maybe(action: () -> ()) {
  if arc4random_uniform(2) == 0 {
    action()
  }
}

maybe {
  println("Hello World?")
}

k0nserv

// Define the ++= operator
infix operator ++= {}
func ++= (action: @autoclosure () -> (), condition: BooleanType){
  unless(condition, action)
}

var x = 1

// This is equal to ruby's
// x = 2 unless 1 > 2

k0nserv

func unless(condition: BooleanType, action: () -> ()) {
  if condition.boolValue == false {
    action()
  }
}

var opt: Int? = 10
unless(opt == nil) {
  println("opt was non nil")
}

k0nserv

func _while_without_while(condition: @autoclosure () -> BooleanType, 
                          action: () -> ()) {
                          
  var loop: () -> () = { $0 }
  loop = {
    // The condition is called each time to 
    // see if the loop should continue
    if condition() {
      // Then the acutal action is called
      action()

k0nserv

(function () {
  "use strict";
  
  // Code..
  
}());

k0nserv

func _while(condition: @autoclosure () -> BooleanType, action: () -> ()) {
  while condition() {
    action()
  }
}

var i = 0
_while(i < 10) {
  println("\(i)")
  i += 1

k0nserv

func _if_without_if(condition: BooleanType, action: () -> ()) {
    // We fake the false case by using an empty closure, e.g a NOP
    let actions = [{}, action]

    // boolValue returns a Bool and we can abuse the fact that
    // hashValue of true is 1 and then hashValue of false is 0 to
    // get the correct closure to run
    actions[condition.boolValue.hashValue]()
}