Thanks for all the help. The simplified example indeed threw away too much. There were no side effects.
Brent, of course I couldn't create your function; though I gained through trying. I then found it useful to consider the type of: fmap (\x -> putStrLn x) getLine which is IO (IO ()) and hence displays nothing to the screen. Felipe, your recursive example was also compelling and concise. Antoine, I see how the join capacity of a Monad can be useful in this issue. I'm also reminded of what <*> can bring to fmap/<$>. On reflection, I often trip up when learning by comparing IO to simpler monads such as [] and Maybe. But [] and Maybe never have effects, and so are poor foils. The ((->) t) monad is henceforth in my toolbox. Paul _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
