Are there any tutorials someone could point me at for creating a terminal based, text interface application for OSX? Something sort of looking like Lotus 1-2-3 for DOS.
It is very common to create such text interface application using the ncurses library.
You can use ncurses from Swift programs by importing it:
Then you can follow ordinary ncurses tutorials to get a grasp on how to build up user interfaces using ncurses.
In particular, you'll probably find the following tutorial helpful. It is on how to use ncurses with Swift - though on Linux. The techniques explained are exactly the same on OS X, except that you need to use the aforementioned import instead of loading the Linux version of the library: