I am back brushing up on Objective C and Cocoa, and now working on Swift. It is supposed to be easy to integrate Swift code with an Objective C project, but I found it difficult. So as I've done before, I've cooked up a working example that is as simple as it could possibly get. I thought I would post a writeup on Dropbox.
It is here. (It's a pdf printed from Sphinx html). The original will be on github soon. Good as long as Dropbox yet lives.