There seem to be a few situations where it's not clear to me when to use "let" and when "where". For instance, in this little example I was playing with to work out what syntax works, main = putStr (show (if maybe_index == Nothing then DP_Unknown else DP_Number index) ++ "\n") where maybe_index = maybe_read word (Just index) = maybe_index or... main = let maybe_index = maybe_read word (Just index) = maybe_index in putStr (show (if maybe_index == Nothing then DP_Unknown else DP_Number index) ++ "\n") Does anyone care? At the moment I use "where" so that at a first glance you get an overall idea of things, then you can read further for details if you like. I was disappointed to find that I don't seem to be able to write things like, main = let maybe_index = maybe_read word in putStr (show (if maybe_index == Nothing then DP_Unknown else DP_Number index) ++ "\n") where (Just index) = maybe_index BTW, is the above a sane way of getting the 'index' 'out of' the "Just"? I often seem to be using a "where (Just foo) = bar" type of idiom. (Of course, there is that special "let" stuff for "do" notation too which doesn't seem to use "in".) I hope all that was somewhat coherent, anyway, or at least sheds light on some of the confusion of newcomers to Haskell! -- Mark