Library to automatically listen to external Swift functions

I wasn't quite sure how to title this one but I will try to explain as best I can what I would like to do.

Basically, I want to create a library that other people can include with their Swift projects that will be able to track when any function is fired (like looking for updates in the stack trace maybe?) or adds pre-compile scripts that would go add hooks (whether that's another function call or just pushing the function name into a global array) to every existing function in the project.

Does anyone have any thoughts on 1) if this is even remotely possible and 2) how it could be done?