Comment by lsllc

It's an exercise in recreating how an Objective-C app works in C from first-principles. For example, the creation of the AppDelegate (see CreateAppDelegate() in AppDelegate.c) is interesting because it shows how to create a class from NSObject and attach the applicationDidFinishLaunching: method along with it's implementation in C. I've used objc_msgSend() before from C (to access the pasteboard from a CLI app), but never implemented any ObjC classes using C!

It's similar how you might attempt to build a C++ class from only C components by creating a vtable.