%3.
declare fun {Curry3 F}
       fun {$ X}
          fun {$ Y}
         fun {$ Z} {F X#Y#Z}
         end
          end
       end
    end

declare fun {Uncurry F}
       fun {$ X#Y#Z} {{{F X} Y} Z}
          end
    end
%4
declare fun {SumProd L}
       case L of
          H|T then local S#P = {SumProd T}
               in S+H#P*H
               end
       [] nil then 0#1
       end
    end

declare fun {FoldL F Acc L}
       case L of
          H|T then {FoldL F {F Acc H} T}
       [] nil then Acc
       end
    end

declare fun {SumProd1 L}
       local fun {F A#B C}
            A+C#B*C
         end
       in {FoldL F 0#1 L}
       end
    end

{Browse {SumProd1 1|2|3|nil}}