Using Playgrounds with this book

Hello fellow coders,

I am writing in the hope that someone here may have some solutions to a couple of issues I am having using playgrounds (not a book issue but the developer forums are failing me) while I am working through the code in this book.

I am finding playgrounds a very frustrating platform to work with. I have set “Run” to “Manually Run” which has seemed to solve the very slow times that playgrounds was taking to compile. While I am editing the files in the “Sources” folder I am continuously getting a popup alert that states “The auxiliary source module did not compile successfully”. Does anyone know a solution or workaround for this please. Any playgrounds streamlining solutions would be much appreciated.



You’ve already found the known solution for problematic playground behavior – leaving them in Manually Run mode. I’ve also added a shortcut stolen from Xcode 10, using Command-Shift-Return to execute the playground.

You’ve probably already found that the “auxiliary source module…” message is caused by a syntax error in one of the source files you are not currently editing. I try to clear those up as soon as I become aware of them so they do not continue to get in my way as I’m working on new code.

I also feel your pain. I was hit with dozens of weird playground behaviour - some that hung forever.

Playgrounds has been a mixed bag from inception. Some releases were fairly stable, but the Xcode 9 ones have been problematic.

There’s been some promising changes for Xcode 10 playgrounds, so hopefully that will help make things easier to work with.