I don't have a comment on the article in question, but I gotta mention that this is the second post I read from these guys and it's always in high quality and neatly organised.
Their post on Enums is better than Apple's docs.
Very well done!
Not sure why openstack swift never went after apple's swift for using the same name. Swift, the opensource object store platform has been around for so many more years and is very well known in the tech world.