I'm sure this isn't a problem with the supplied source code, but I wanted to see if the author or other users had found a solution.

The problem is every time I open a playground in Xcode, after an hour or so Xcode hangs when I attempt to move to another page in the playground, and I have to force quit. The playground is forever unusable after that point because the same happens if I reopen Xcode and switch to the same page. It has happened in both ch02 and ch03 so far.

I found one suggestion online to change the playground's platform from iOS to macOS - which did help briefly in ch03. But the same problem came back after returning to this playground a few days later. I also set all my playgrounds to run manually but that doesn't help either.

At this point, I have no confidence that Xcode will be usable for me. I've seen lots of complaints about this issue and nothing from Apple.

Update as I was composing this post: now Xcode is totally unusable because it reloads the (corrupted?) playground every time. Oh well!

Any ideas? Thanks

Xcode 10.1
macOS Mojave v10.14.2
iMac (Retina 5K, 27-inch, 2017)
4.2 GHz Intel Core i7
16 GB 2400 MHz DDR4
Radeon Pro 580 8192 MB

For some people, playgrounds can hang. I experience the same issues. You don't want to know how often I had to kill and restart Xcode while I was setting up the playgrounds files

I can recommend manual mode still (works a bit better for me), and sometimes removing "import UIKit" saves some framework loading time, making it a bit snappier.

Unfortunately, I can't help more with making playgrounds faster, I recommend heading over to the official swift forums (http://forums.swift.org/) and ask for help from Apple's engineers.