| I'm sorry, I had a small error in my code. It should have been: | | >go filelist = mapM go' filelist -- no "do return" | > where go' f = do h <- openFile f ReadMode | > text <- hGetContents h | > let c = head $! text | > return (c `seq` (hClose h `seq` c)) I don't think the "do return" bit matters. If you change the last line to c `seq` (hClose h `seq` return c) is the behaviour changed? J