This document covers how to use the BBC micro:bit template book to create your own Swift Playground book. It does not include details on the format of the playground books or the markup of the Content.swift files.

The term Swift Playground can have different meanings. When we refer to a Swift Playground we mean a Swift Playground Book. The book format allows for the creation of chapters and pages such that it is structured in a book format.

For a complete description of the Swift Playground book format please refer to the Apple documentation. You should familiarise yourself with this documentation before attempting to create your own book.

Creating a Swift Playground from scratch is a complex programming task. By providing a template book we have written all the complex code required to pair and communicate with the micro:bit over Bluetooth. You can think of the template book as providing a Playground SDK (Software Development Kit).

The template book is provided in this repository as micro-bit template.playgroundbook

After cloning this folder, you should rename it to something appropriate but keep the extension .playgroundbook

On a Mac OS computer this will appear as a file bundle which means it appears as a single file but is actually a directory structure. To open the directory structure, you need to select the book and choose Show Package Contents from the Finder's contextual menu.

To edit the book you will ideally require a tool suitable for editing Swift and plist files. We would recommend downloading Xcode from the Apple App Store.

The files you need to edit are located in Contents/Chapters/ You will also need to edit the appropriate manifest.plist files. Refer to the Apple documentation on details of this.

Inside the Contents/Sources directory you will find all the source files required for the playground to communicate with the micro:bit as well as a host of other supporting functionality. These may also provide an additional insight into the functionality of our Swift Playground SDK.

To test your book you can either:

• Copy it to the Playgrounds folder in your iCloud drive. The Swift Playgrounds app on your iPad will notice it has been added/updated and download it accordingly.
• Airdrop the playground book from the Finder to your iPad, then respond accordingly on the iPad. This is fine the first time you copy the book but subsequent drops will make copies of the book which will build-up over time and need to be deleted.
• Utilise a script file as detailed below or author an Automator action.

The Apple documentation also lists various ways of getting your playground onto a device.

This repository also contains another Swift Playground book called microbit API.playgroundbook

This playground provides an interactive demonstration of the whole of the API we have defined for interacting with the micro:bit much of which is not included in the Intro book. You may wish to install this to your iPad and explore it before developing your own book as it will illustrate the many possibilites that are possible from the Swift Playgrounds app.

The repository also contains three script files:

• create_doc_book.sh
• create_intro_book.sh
• create_template_book.sh

These were used by us to the create the micro:bit API, Intro to the BBC micro:bit and micro-bit template playground books. These scripts copy and compile the micro-bit source book and then merge the books' contents from separate folders. You may wish to copy and modify one of these scripts for your own workflow. They contain lines to compile the original storyboard and assets from the source book. Unless you intend to modify the storyboard or assets then you should just work from the compiled template book instead.