I am getting the following error when trying to do a show on a Ranges object :- C:\Languages\Haskell>ghci rangeTest.hs GHCi, version 6.12.3: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package ffi-1.0 ... linking ... done. [1 of 1] Compiling Main ( rangeTest.hs, interpreted ) Ok, modules loaded: Main. *Main> main Loading package array-0.3.0.1 ... linking ... done. Loading package containers-0.3.0.0 ... linking ... done. Loading package ranges-0.2.3 ... linking ... done. Ranges [(37*** Exception: <stdout>: hPutChar: invalid argument (character is not in the code page) *Main> I have attached the test source also :- import Data.Ranges test = (ranges [ range 32 33, range 34 35, range 37 39 ]) main :: IO () main = do { putStrLn (show test) } I am probably doing something fundermentaly wrong. Many thanks in advance, Aaron