The problem is that if `f4` is exported, everything it includes gets exported too, without any way to restrict it. Plus other tuple quirks. But it's a cool way to inline nevertheless.
Still hope one day there will be some sugar or other optional way to inline objects. Nim is amazingly elegant and laconic, and verbose declaration of nested objects is the only thing that is not as elegant and laconic as it probably could be — to my newcomer's eyes, at least.
