úÎ,•  %A class that knows how to access the nth member of a  type.  Example:  nth d1 (1,2) == 1  nth d2 (1,2) == 2  nth d3 (1,2) == error!   extended to work on any  type.   extended to work on any  type.         nthable-0.1 Data.NthableNthablenthfstsndthrdfrthffthsxthsvnthbase Data.Tuple