Hi Max, Wow! I tried both *sequence* and *replicate* but guess I didn't put them together properly. I didn't even know there was a *replicateM*. Much cleaner. Thanks Michael --- On Sun, 7/25/10, Max Rabkin wrote: From: Max Rabkin Subject: Re: [Haskell-cafe] Random this! ;-) To: "michael rice" Cc: haskell-cafe@haskell.org Date: Sunday, July 25, 2010, 11:44 AM On Sun, Jul 25, 2010 at 5:39 PM, michael rice wrote:

I know, ugly, but at least I got it to work. What's a better way to generate this list?

rollNDiceIO n    = sequence . replicate n $ randomRIO (1,6) {{ sequence . replicate n = replicateM n }}    = replicateM n $ randomRIO (1, 6) --Max

Cool. Everything's there but the N. Learning Haskell is a lot like learning to dance. Michael --- On Sun, 7/25/10, Ozgur Akgun wrote: From: Ozgur Akgun Subject: Re: [Haskell-cafe] Random this! ;-) To: "Max Rabkin" Cc: "michael rice" , haskell-cafe@haskell.org Date: Sunday, July 25, 2010, 3:17 PM Sorry but I'll just go ahead and eta reduce it :) rollNDiceIO = flip replicateM $ randomRIO (1,6) On 25 July 2010 16:44, Max Rabkin wrote: On Sun, Jul 25, 2010 at 5:39 PM, michael rice wrote:

I know, ugly, but at least I got it to work. What's a better way to generate this list?

rollNDiceIO n   = sequence . replicate n $ randomRIO (1,6) {{ sequence . replicate n = replicateM n }}   = replicateM n $ randomRIO (1, 6) --Max _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ozgur Akgun

Hi Lyndon, Since the example immediately above the exercise used randomRIO, I assumed that randomRIO was to be used as part of the solution to the exercise. http://en.wikibooks.org/wiki/Haskell/Understanding_monads/State Also, it was the above mentioned example that introduced me to *liftM2*, about which I posted a question a couple of days ago (subject line: Heavy lift-ing). The next topic on the wiki page is "Getting Rid of the IO" which seems to be the direction of your post. No doubt I'll have more questions as I plod on. Thanks for your input, Michael --- On Mon, 7/26/10, Lyndon Maydwell wrote: From: Lyndon Maydwell Subject: Re: [Haskell-cafe] Random this! ;-) To: "michael rice" Cc: "Max Rabkin" , "Ozgur Akgun" , haskell-cafe@haskell.org Date: Monday, July 26, 2010, 8:29 AM I find it useful to have a seed argument to nearly all random functions rather than using ones with an IO signature. This way you can speed up your program quite a bit and also make testing much easier. I think that MonadRandom does this automatically too.