On: What's new in Swift 4.1

Most Swift code is divided nicely up into modules, which are compiled together and have their own namespace. https://developer.apple.com/library/content/documentation/Sw...

For some reasons most of the swift code I've seen doesn't use any namespace/prefix when it calls various functions from different "modules". It's used just like C "include"

You only have to qualify what module something is from if it would otherwise be ambiguous.