Your forgetfulness boosted my ego for a few seconds - I wasn't the only one! :) Thanks very much, that's a big help. Iain On 24 Sep 2008, at 10:10 pm, Lev Walkin wrote:
forgot return, of course:
myTake :: IO [Int] myTake = do n <- rand 1 10 return $ take n [1..10]
Lev Walkin wrote:
Iain Barnett wrote:
Hi,
I have a function, that produces a random number between two given numbers
rand :: Int -> Int -> IO Int rand low high = getStdRandom (randomR (low,high))
(Naively) I'd like to write something like
take (rand 1 10 ) [1..10]
and see [1,2,3,4] ... or anything but nasty type-error messages. myTake :: IO [Int] myTake = do n <- rand 1 10 take n [1..10] or myTake = rand 1 10 >>= \n -> take n [1..10] or myTake = rand 1 10 >>= flip take [1..10] I'm reading about 6 tutorials on monads simultaneously but still can't crack this simple task, and won't pain you with all the permutations of code I've already tried. It's a lot, and it ain't pretty.
Would anyone be able to break away from C/C++ vs Haskell to help? Just a point in the right direction or a good doc to read, anything that helps will be much appreciated. Monad enlightenment happens after 7'th monad tutorial. Verified by me and a few of my friends.