Given a list of decimal digits represented by Integers between 0 and 9--for example, the list [1,2,3, 4]--with the high-order digit at the left, the list can be converted to a decimal integer n using the following formula, an instance of Horner's rule: n = 10 * 10 * 10 * 1 + 10 * 10 * 2 + 10 * 3 + 4 = 10 * (10 * 10 * 1 + 10 * 2 + 3) + 4 = 10 * (10 *(10 * 1 + 2) + 3) + 4 In Haskell, the foldl function neatly captures this pattern: horner :: [Integer] -> Integer horner = myFoldl timesPlus 0 where timesPlus x y = 10 * x + y What is the direct recursive calculation of this function without using the call to foldl? In other words, what's the second equation of: horner2 :: [Integer] -> Integer horner2 [] = 0 horner2 (x : xs) = ? Given that we've already got the definition using foldl, it ought to be easy to express the second equation, but it's eluding me. Thanks. _________________________________________________________________ Windows Live™ Groups: Create an online spot for your favorite groups to meet. http://windowslive.com/online/groups?ocid=TXT_TAGLM_WL_groups_032009