I've been playing around with "The Little MLer" (pg. 95, 96) to try to improve my understanding of types. I can ask ML: - ints(0); val it = Link (1,fn) : chain - and Haskell: *Main> :t ints 0 ints 0 :: Chain *Main> ints 0 <interactive>:1:0: No instance for (Show Chain) arising from a use of `print' at <interactive>:1:0-5 Possible fix: add an instance declaration for (Show Chain) In a stmt of a 'do' expression: print it *Main> I think I need to write a show function for type Chain but not sure how to proceed. Michael =============== ;;ML datatype chain = Link of (int * (int -> chain)) fun ints(n) = Link(n + 1, ints) ;;Haskell data Chain = Link Int (Int -> Chain) ints :: Int -> Chain ints n = Link (n+1) ints