Is it OK for Xcode project names to contains dashes? Are underscores preferred?

Question

Are dashes or underbars preferred in Xcode project names? Does it matter? Should I use neither? I want to break out my project into several sub-projects and use a workspace.

MyApp-iOS-UI

MyApp-iOS-Model

vs.

MyApp_iOS_UI

MyApp_iOS_Model

vs.

MyAppiOSUI

MyAppiOSModel

I haven't easily been able to find a definitive answer. It's my first Xcode project and I don't want to hit a snag.

I want to support back to iOS 9, if possible. The app will also need to interact with a macOS app at some point, so I'll need a macOS project folder too.

Answer 1

This SO question might help. Basically, underscore is preferred, as non-alphanumeric characters are replaced with underscore anyway.