There are a couple things I just discovered about “pragma mark” that you might want to mention in the book.
First off, I have never been able to get it to work as shown in the book when I tried to use it in the past. Some googling revealed the reason–in Xcode preferences, under the Code Sense tab, the option “Sort list alphabetically” has to be unchecked. I must have checked it long ago.
Second, there cannot be a space after the hyphen, such as usually happens when you copy & paste code from a PDF :) Otherwise the menu displays a hyphen instead of a separator.
Hope this helps others.