I'm halfway through a 12-week stint at the Recurse Center. One of the first things I did was to write a silly chess app called "ChessFidget" to help myself learn Swift. Here's more about it, including the source code. There's a link in the README to a double-clickable binary you can run without having to compile the code.

Here's a 5-minute presentation I gave about it:

The Incredible Shrinking Docs

Wouldn't you know, I was wondering about documentation in Xcode 8, and indeed it has fundamentally changed. The DevPubs team has hugely reduced the size of the docs and apparently integrated them with Xcode so that there is no longer a need for a separate download step.

Running the Xcode 8 beta, I find I'm able to browse the docs with WiFi turned off. I know I'm looking at the Sierra docs, because NSGridView is there. Furthermore, docsets are no longer listed in the Downloads pane of the prefs panel. It's like magic — kudos to the DevPubs team!

I'm guessing this news about the docs was announced during the Platform State of the Union. I missed that session when it was live-streamed, so I'll have to watch it later. I'll see if it confirms my understanding, and I'll think about implications for AppKiDo.

The Developer Tools people at Apple have a lot of momentum lately. I can't remember when it felt so much like they were working hard to connect with us, to show that they hear us (the culture around Swift seems incredibly positive), to create cool tools, and to take away pain points.

I wonder if squashing the documentation size was important not only for Xcode but for the Swift Playgrounds iPad app and/or future possibilities for using iPads for development.

The New Adventures of Old AppKiDo

I have been making progress on a reboot of AppKiDo, which is a Mac app that I wrote for browsing the Cocoa documentation that comes with Xcode. AppKiDo stopped working in 2014, during the betas of Xcode 6, because of changes in the structure of Apple's docsets.

I now have it up and running again, in a preliminary but usable form. (The code is in a private repository; I will push it to the public one after ironing some things out. [UPDATE: Eh, why wait? The code is public at Remember, it's very much a work in progress.])

The best news, aside from having it run at all, is that it's launching much more quickly than it used to. There's still a lag, but it's much shorter now, because instead of laboriously parsing all the HTML files, I get almost everything I need from the Core Data store inside the docset.

There are serious limitations in the current version that will take time to address:

  • Still Objective-C API only. For example, if you search for "string" the search results won't include the Swift String class.
  • Xcode must be at /Applications/
  • You have to pick the docset you want to browse at launch time.
  • Window states aren't saved between launches.
  • The "ALL" options are missing (as in "ALL Class Methods", "ALL Instance Methods", etc.).
  • And more.

As I write this, the keynote for WWDC 2016 is hours away. For the first time in a long while I am experiencing an old familiar feeling of suspense. Will there be some change to the docs in Xcode 8 that will upend everything I've been doing?

Quick Explanation of the Term "Application Bundle"

Follow-up to my previous post about receipt files. Again, this is Mac-centric.


"Application bundle" is Cocoa developer terminology for an application as it exists in the file system of your computer. The application consists of a number of files organized in a directory. The directory has special attributes and has a specific subdirectory structure.


You only think you see a regular file. When you see an application icon in the Finder, such as the Safari icon, it looks like any other file icon. However, the Finder is telling at least two and possibly three lies about the application.


On the file system, the name of the application is not actually "Safari" (for example) but "", with a ".app" extension.

You can see all the .app extensions in Terminal:

ls /Applications

You can also see an application's filename in the Finder by selecting the application icon and doing a Get Info. You'll see the ".app" extension. Alternatively, if you go to Preferences > Advanced and turn on "Show all filename extensions", you'll see the .app extensions for all apps.


An application is not a regular file, as it appears to be in the Finder, but a directory with special attributes and specific subdirectory structure. Such a directory is called a "bundle".

You can see the subdirectory structure in Terminal:

ls -l /Applications/
ls -l /Applications/

You can also see the directory structure in the Finder by right-clicking the application icon and selecting "Show Package Contents". You will see there is a subdirectory called "Contents", and within that there is a bunch of other stuff.


Usually the Finder displays the name of the application as the directory name minus the ".app" extension. Thus, "Safari" instead of "", "Contacts" instead of "", etc.

However, it is possible for applications to specify a different name to display in the Finder. The main reason for this is to localize the displayed application name. It is very rare to encounter this "lie" if English is your Mac's primary language.

Search for the term "CFBundleDisplayName" for the nuts and bolts of how developers get their apps to do this.