I liked this app a lot. It wont make you a programmer overnight, but its a nice overview of the basics in bite-size lessons. I like the Compendium at the end of each chapter, allowing you to quickly reference that chapters concepts.
I HIGHLY recommend you try the examples for yourself. I dont have a Mac, but was able to try out all the examples online with pages like SwiftStub.
JayEllBee about Swifty: Learn to code tutorials for Swift