As far as I’m concerned, it’s impossible to spend too much time talking about Disney World. You may not agree, and you’re wrong that’s okay.

This week, I joined the Average Dis Nerd on his eponymously named podcast. (His podcast is kinda sorta The Talk Show, but with a Disney/Universal theme). On this episode, we discussed a variety of topics, including Disney+, technology at Disney parks, Disney’s iOS offerings for parkgoers, cameras at Disney World, and more.

I had a blast on this one; I hope you like it too.


Curiously, it all started with a trip to Disney World.

We went for my son’s fifth birthday. He hadn’t been to Disney since he was barely more than an infant. Our daughter, Mikaela, had never been.

Ever-so-independent, even just shy of two years old, Mikaela had strong opinions about everything when she was willing to ride in the stroller. After a few days at Disney, my wife and I discovered what would calm her down: browsing the Photos app on our phones, looking at the pictures we had taken on the trip so far.

This was utterly terrifying.

Photos isn’t really designed for this, and makes it possible — if not easy — to delete or edit photos. Given that these were the only copies of photos we had taken on the trip, I was scared that Mikaela would accidentally delete one or more of them.

Once we got home from our trip, I knew which app I wanted to write.


Peek-a-View Quick Walkthrough

Peek-a-View is, at its core, a read-only photo browser.

It is designed to be safe to hand to anyone, and know that you’re not going to need to worry about the safety of your photos.

When paired with Guided Access — the Apple tool that lets you lock your phone into one app — it is the perfect Mikaela-safe photo browser.

Peek-a-View can be used for other reasons though. Perhaps you’re showing off a series of screenshots to a client. Perhaps you want to share your vacation pictures with a friend, but only your vacation pictures. Peek-a-View also lets you select a particular album to view, thus limiting inquisitive eyes to only the photos you know are safe.


Peek-a-View, like Vignette, has a free tier, with a one-time $5 purchase to unlock more functionality.

Peek-a-View is limited to showing only the 20 most recent media items for free; the unlocked version has no such limit. Furthermore, if you do unlock Peek-a-View, you also get a series of fun alternative icons you can choose from.

Business Casual

Eco Friendly

Flat and Friendly

High Contrast



I owe a great debt of gratitude to my friends Jelly and Ste. Jelly (of GIFWrapped fame) gave me a ton of technical help, and some design pointers as well. Ste (more at his website) did the app icon, store screenshots, as well as providing many suggestions for Peek‑a‑View’s design.

I’d be honored if you gave Peek-a-View a try, and even more so, if you decided to throw a few bucks my way for making it.


This week I joined Jonathan Ruiz and Mark Fransen on their tech show, Everyday Robots. On this episode, we discussed my history as a developer, my journey into being an iOS developer, and finally my transition into being an indie.

Though Analog(ue) is probably the canonical podcast series about my history and journey of the last few years, this episode of Everyday Robots is a really terrific summary. If you want a ~75 minute answer to “who the hell is Casey?”, this episode is it.


On a recent ATP, I recapped my family’s recent trip to Disney World. It was brief, but it was fun.

Glenn & Chris of the Starport75 podcast reached out and asked if I would be interested in joining them on their Disney World podcast.

Um, yes.

On this wide-ranging episode, we discussed my history with Disney, the Disney Dining Plan, photo strategies, Galaxy’s Edge, DVC rentals, and the Disney Cruise Line.

It was a ton of fun to join Chris & Glenn; they were gracious hosts and let me blab more than I probably should have.

If you’re a Disney fan at all, you should check it out.


This week I joined Lisa Schmeiser, Dan Moren, and Mikah Sargent on Clockwise.

In this episode, we discussed our [probably questionable] security practices, services we yearn for, Twitter’s experiments with reply limitations, and apps we’ve recently fallen in love with.

Fast and fun without fail, Clockwise is always a blast.


One of my favorite holiday traditions — the Do By Friday holiday party — has happened again. As with last year’s, my fellow ATP co-hosts and I joined the Do By Friday hosts, including Kevin Budnick, to have a holiday party.

To discuss the goings-on of the episode is to take an express train to Spoiler City, so I’ll just say that this one was a fun one.

Neat Swift Trick: AnyIterator

As with all programming posts, we start with a completely contrived example that makes no sense in the real world.

Say you’re writing ListOfIntegers, which is, well, a list of integers. In the real world, you’d absolutely use Array<Int> or something similar. Just go with me on this.

We can start this way:

class ListOfIntegers {
    typealias Element = Int
    private var backingStore = [Int]()

    init() { }
    init(_ value: [Int]) {
        self.backingStore = value

At a minimum, you probably want your ListOfIntegers to be a Sequence, so you can iterate over your list. Thus, you need to provide a makeIterator() function. This provides the Iterator that will allow Swift to perform that iteration.

Creating an Iterator seems like a whole lot of work, involving making a whole new subtype. No thanks. I’m lazy; that’s why I’m a developer.


This week I discovered a very neat shortcut: AnyIterator<T>. When I first saw this struct, I thought it was simply there for the purposes of type erasure. Looking through the class documentation, however, I found this gem:

/// Creates an iterator that wraps the given closure in its next() method.
init(_ body: @escaping () -> Element?)

Wait… what?

If you look at IteratorProtocol, it’s rather simple:

public protocol IteratorProtocol {

    /// The type of element traversed by the iterator.
    associatedtype Element

    /// Advances to the next element and returns it, or 
    /// `nil` if no next element exists.
    mutating func next() -> Self.Element?

Suddenly AnyIterator<T>'s init(:)'s comment makes sense:

Creates an iterator that wraps the given closure in its next() method.

By providing a closure to the init(:), we can provide an implementation for this Iterator's next() method. Sweet!

Adding an Iterator to ListOfIntegers

We can leverage this to easily add an Iterator to our ListOfIntegers:

class ListOfIntegers: Sequence {
    typealias Element = Int
    private var backingStore = [Int]()
    init() { }
    init(_ value: [Int]) {
        self.backingStore = value
    func makeIterator() -> AnyIterator<Int> {
        // We establish the index *outside* the
        // closure. More below.
        var index = self.backingStore.startIndex
        // Note the use of AnyIterator.init(:) with 
        // trailing closure syntax.
        return AnyIterator { () -> Int? in
            // Is the current index before the end?
            if index < self.backingStore.endIndex {
                // If so, get the current value
                let currentValue = self.backingStore[index]
                // Set a new index for the next execution
                index = self.backingStore.index(after: index)
                // Return the current value
                return currentValue
            } else {
                // We've run off the end of the array, return nil.
                return nil

A couple things to note here:

  1. We’re expressly returning AnyIterator<Int> instead of the default ListOfIntegers.Iterator. The latter would require us to have a second typealias to specify the type of the Iterator; by being explicit, the compiler can infer ListOfIntegers.Iterator to be AnyIterator<Int>.
  2. When I first wrote this, I made the rookie mistake of creating var index within the closure. This meant that every time the iterator was asked to move to the next element, instead it just started over. 🤦🏻‍♂️ Thus, it’s important to create your index outside the closure, so it doesn’t get reset every time you call next().
  3. Since we’re using an Array<Int> as our backing store, a much simpler implementation would be to simply
    func makeIterator() -> Array<Int>.Iterator { 
        return self.backingStore.makeIterator() 
    but that would defeat the purpose of this post.

I don’t often find myself in a situation wherein I need to create a custom Sequence; much less, a custom Iterator for that Sequence. However, when I find myself needing a custom Iterator in the future, I’ll certainly start with AnyIterator<T>.

If you’d like to play with this in a Playground, I’ve put the code up in a gist. Just copy/paste that into a new Playground.


It’s the holidays, so the ATP Store is back!

For this season, we have a new retelling of an old story. We’re continuing to suck what we can out of returning to the //////ATP logo, but this time, doing so in six colors and two modes.

All the shirts are available in both men’s and women’s cuts, in tri-blend and 100% cotton.

First we have ATP’s take on the Six Colors theme:

Shirts in light mode

Additionally, we have the same in Dark Mode:

Shirts in dark mode

We also have some older merchandise returning:

Everything except the pins is available for pre-order until Sunday, November 17. Don’t miss out! Every year we hear stories of people who procrastinated, and then missed out! Don’t be that person. Order now!


I can’t remember the first time I saw Sneakers, but I was surely no more than around ten years old. A nerd since birth, but more recently discovering my future as a computer nerd, Sneakers spoke to me like few movies of the time were able to. It was fun, interesting, and exciting.

I didn’t understand half of it, but I didn’t care.

As a grown man, I can see there’s so much more to Sneakers than I had ever understood as a kid. It’s a much deeper movie than I gave it credit for, and in these awful times, more prescient than I’m comfortable with.

As I’ve said before, I consider The Incomparable to be the major leagues of podcasting. I’ve appeared on the show a couple times before, and every time, it’s a tremendous honor.

On this episode, I was joined by host Jason Snell, my ATP co-host John Siracusa, Erika Ensign, and Dan Moren to discuss the film. I had a blast, and if you’re my kind of nerd, I think you will enjoy it too.

One of these days, if I’m asked to return, I’ll remember to come up with a pithy closing remark. 🤦🏻‍♂️


This week I joined Brianna Wu, pinch-hit blast-from-the-past host Jason Snell, and my long-lost-twin Dan Moren on Clockwise.

In this episode, we discussed our plans for macOS Catalina, the software/hardware we’d most/least like to lose, good OSes on bad hardware, and the legality of accessibility on the web.

Clockwise is always fun and always fast. If you’ve somehow missed out on the show so far, today’s a great day to jump in.