Fwd: [Haskell-cafe] turning an imperative loop to Haskell

Sorry, forgot to cc list

I think this is called taking a good thing too far, but cool too:

f1 u = u + 1 f2 u v = u + v f3 u v w = u + v + w

-- functions renamed for consistency) zipWith1 = map zipWith2 = zipWith

-- and hey presto! us1 = 3 : zipWith1 f1 us1 us2 = 2 : 3 : zipWith2 f2 (drop 1 us2) us2 us3 = 2 : 3 : 4 : zipWith3 f3 (drop 2 us3) (drop 1 us3) us3

How about this: import Data.List -- for transpose f = sum zipWithN fn = map fn . transpose us k = s where s = [2..k+1] ++ (zipWithN f $ x $ map (flip drop s) [0..k-1]) take 10 (us 1) [2,2,2,2,2,2,2,2,2,2] take 10 (us 2) [2,3,5,8,13,21,34,55,89,144] take 10 (us 3) [2,3,4,9,16,29,54,99,182,335] take 10 (us 4) [2,3,4,5,14,26,49,94,183,352] We can always take it further :D Stephen