Learning Swift by working through example code in playgrounds


Swift Playgrounds

Some experiments with Playgrounds in XCode 6 using the Swift programming language.

I've started the process of converting everything over to Swift 2.0 and XCode7. I'll leave this in a separate branch for now until the new playgrounds stabilise.

The Swift Programming Language Book

I have been working through all the examples in the book Apple Inc. “The Swift Programming Language.” iBooks. https://itunes.apple.com/au/book/swift-programming-language/id881256329?mt=11. Each .playground file in the project relates to a chapter from the Swift Programming Language book.

I have implemented this as a single XCode project that contains a playground file for each chapter of the language reference book. I'm finding it quite useful to have this project open when I am writing Swift code as I can use the project wide search functionality to lookup any Swift features or syntax that I am unsure about (so long as I can remember the words to look for)

Below is a list of each of the files within the project (this is also a list of the chapters of the book that I have worked through).

  • ASwiftTour.playground contains the code from the "Swift Tour" chapter. It touches on most of the unusual features of the language and is easy to search through to find examples. It is a large file and does tend to give the swift interpreter a rather hard time. Any syntax errors in the file are likely to crash SourceKit.

Chapters from the Language guide. Each chapter goes into depth about its particular subject.

  • TheBasics.playground This chapter covers basic value types like Strings, Ints, Bools and floats. The notation for exponent values in float literals is interesting. Comments are covered (nested /* */ comment blocks). TypeAlias is covered as are tuples. Optionals are touched on and assertions are mentioned.
  • BasicOperators.playground Arithmetic, remainder, increment, decrement, comparison, unary, ternary, range (closed and half-closed) and logical operators. There are examples of all of them.
  • StringsAndCharacters.playground Some details about Unicode literals (multi-byte characters). The countElements() function for finding the length of a string. Concatenating strings, Comparing strings and Interpolating strings (not much on splitting or parsing strings).
  • CollectionTypes.playground
  • ControlFlow.playground
  • Functions.playground
  • Closures.playground
  • Enumerations.playground
  • ClassesAndStructures.playground
  • Properties.playground
  • Methods.playground
  • Subscripts.playground
  • Inheritance.playground
  • Initialization.playgroung
  • Deinitialization.playground
  • AutomaticReferenceCounting.playground
  • OptionalChaining.playground
  • TypeCasting.playground
  • NestedTypes.playground
  • Extensions.playground
  • Protocols.playground
  • Generics.playground
  • AdvancedOperators.playground

That completes the Language Guide section of the book. I haven't decided if I will continue on with the Language reference section next or switch over to the "Using Swift with Cocoa and Objective-C" book.

Using Swift with Cocoa and Objective-C Book

There are six playground files that work through the code in the “Using Swift with Cocoa and Objective-C.” iBook. https://itunes.apple.com/au/book/using-swift-cocoa-objective/id888894773?mt=11. They are listed below. The example from this book didn't translate as well to the playgrounds as the previous book examples did.

  • BasicSetup.playground
  • InteractingWithObjective-C-APIs.playground
  • WritingClassesWithObjectiveCBehaviour.playground
  • WorkingWithCocoaDataTypes.playground
  • AdoptingCocoaDesignPatterns.playground
  • InteractingWithC-APIs.playground

Swift Standard Library

The documentation for the Swift Standard Library can be found at the following link https://developer.apple.com/library/prerelease/ios/documentation/General/Reference/SwiftStandardLibraryReference/. There is a wealth of information contained in the standard library doc and it is nicely organised so that it is easy to experiment with in a playground environment. I have attempted to extend the examples somewhat to try and show off some of the other features of the standard library.

  • String.playground
  • Array.playground
  • Dictionary.playground
  • NumericTypes.playground
  • Protocols.playground
  • FreeFunctions.playground
  • Undocumented.playground

Swift Blog

The Swift blog contains several articles detailing interesting information about the developing language.

  • 2014-08-15 Value and Reference Types
  • 2014-08-05 Boolean
  • 2014-07-28 Interacting with C Pointers
  • 2014-07-23 Access Control


Lots of great articles delving into the finer points of Cocoa programming. The recent articles on Swift are always interesting to go through

  • 2014-08-08 Swift Literal Convertibles Shows how you can create types of your own that can be written as literals when you use them.

What next?

Here are some links to other projects around the web that I would also like to implement