Mark D. Niemiec writes: > In general, f/ produces less than useful results if f's output > type is different than it input types. This can be doubly true if > the parameters themselves have different types and/or shapes. > (+/ */ +./ ,/ ,&.</ etc. are useful; =/ e./ i./ ":/ generally aren't) f&.>/y can be quite meaningful even when f/y is not.