[Haskell-beginners] How can I fix this 'where' error ?

S. H. Aegis shaegis at gmail.com
Sun Apr 6 00:13:29 UTC 2014


Hi.
I'm new to Haskell. I try to solve Euler Project for studying Haskell
through Googling, reading books.
There is a error in where sentence, but I can't fix this.

maxEleList :: String -> String -> [Int]
maxEleList xs ys = maxOfTwo upperList lowerList
where upperList = map turpleSum $ zip (toIntList xs) (toIntList ys)
lowerList = map turpleSum $ zip (toIntList xs) (tail $ toIntList ys)

Error message is
~/maxPathSum.hs: line 4, column 75:
  Parse error
  Error message:
    Parse error: =
  Code:
      maxEleList xs ys = maxOfTwo upperList lowerList
      where upperList = map turpleSum $ zip (toIntList xs) (toIntList ys)
    > lowerList = map turpleSum $ zip (toIntList xs) (tail $ toIntList ys)


How can I fix this?
Thank you for your kind help.

S. Chang


----------------
This code is for Euler project: problem 18, and whole code is like this...
(Not yet finished...)

maxEleList :: String -> String -> [Int]
maxEleList xs ys = maxOfTwo upperList lowerList
where upperList = map turpleSum $ zip (toIntList xs) (toIntList ys)
lowerList = map turpleSum $ zip (toIntList xs) (tail $ toIntList ys)
maxOfTwo :: [Int] -> [Int] -> [Int]
maxOfTwo [] [] = []
maxOfTwo (x:xs) (y:ys) = max x y : maxOfTwo xs ys

turpleSum :: (Int, Int) -> Int
turpleSum (x, y) = x + y

toIntList :: String -> [Int]
toIntList = map (\x -> read x :: Int) . words

rowData :: [[Int]]
--rowData = reverse $ map (map (\x -> read x :: Int) . words) [r1, r2, r3,
r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15]
rowData = map (map (\x -> read x :: Int) . words) [r1, r2, r3, r4, r5, r6,
r7, r8, r9, r10, r11, r12, r13, r14, r15]

r1 = "75"
r2 = "95 64"
r3 = "17 47 82"
r4 = "18 35 87 10"
r5 = "20 04 82 47 65"
r6 = "19 01 23 75 03 34"
r7 = "88 02 77 73 07 63 67"
r8 = "99 65 04 28 06 16 70 92"
r9 = "41 41 26 56 83 40 80 70 33"
r10 = "41 48 72 33 47 32 37 16 94 29"
r11 = "53 71 44 65 25 43 91 52 97 51 14"
r12 = "70 11 33 28 77 73 17 78 39 68 17 57"
r13 = "91 71 52 38 17 14 91 43 58 50 27 29 48"
r14 = "63 66 04 68 89 53 67 30 73 16 69 87 40 31"
r15 = "04 62 98 27 23 09 70 98 73 93 38 53 60 04 23"
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