Trying to mix Swift code with Objective C, I noticed that Swift functions with optional parameters don't get exported in the umbrella header file (product-Swift.h) and so cannot be used inside ObjC code.
This for example:
func aFunc(number:Int?) {...}
does not show up in the umbrella header. But this function does, because the parameter is not optional:
func aFunc(number:Int) {...}
Why?