How to implement a complex NSDocument-based app that imports and exports non-native file types?
I'm working on an app that supports a very complicated set of operations. It's akin to something like Xcode, in that the main document is represented by something like a project window, with numerous entries in it. The document on disk is a bundle (meaning a directory with a file & folder structure underneath). There is at least one file type that it can import and export ( .mfst), but it's not intended to directly edit this file type. That is, opening this file type results in a native document type being created, and the contents of the file being imported into it. The on-disk file is a