I wasn't aware that C++ could do this. It's come on a long way since I last looked at it! How far can it take these dependent types?

Can you specify a function in the type signature that is called by the compiler that can determine the type of the parameter?

Something like :

    stringOrInt:: Bool -> Type
    stringOrInt True = String
    stringOrInt False = Int

    doSomething:: x: Bool -> StringOrInt x -> String

doSomething can then be called like :

    doSomething True "Ook"
    doSomething False 4