What exactly are functions? Let’s talk about functions, methods, callables and closures - what they are, what you can give them, what they can give you, what you can do with them … and what’s inside.
So you’ve released a library! Now you need to maintain it. You want to add features, restructure the code, fix bugs, and maybe improve the library’s usability. Your users just want their code to carry on working. That’s okay!
