If you create blah.gd or any file format the editor recognizes, it updates the Tree in the editor with the item you created from your OS's file manager. How does it know when to do it? I've got a few probably overly-complicated ideas on how it is done but I am really hoping there is a signal or notification that is hooked into to pull that off or that I'm missing something obvious.

Every operating system can notify your application about changes in the file system. For example .NET api on windows has FileSystemWatcher class that does that. On linux there is inotify system which is part of the kernel etc...

Reduz: "The only reason inotify/kqueue is not used is portability (there is nothing like this on other OSs). The scan is not really that expensive though, as a lot of information is cached"

a year later