Validate International Securities Identification Number: Difference between revisions

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@@ Line 1,485: / Line 1,485: @@
 Or, making alternative choices from the standard libraries:
-<lang haskell>import qualified Data.Map as M
+<lang haskell>import Data.Bifunctor (first)
-import Data.Bifunctor (first)
+import qualified Data.Map as M
 import Data.Maybe (fromMaybe)
+-------------------- VALID ISIN STRING -------------------
-validISIN, isinPattern, luhn :: String -> Bool
-validISIN = (&&) . isinPattern <*> (luhn . (show =<<) . stringInts)
+validISIN :: String -> Bool
+validISIN =
+  (&&) . isinPattern
+    <*> (luhn . (show =<<) . stringInts)
+isinPattern :: String -> Bool
 isinPattern s =
-== length s &&
+== length s
-  all (`elem` capitals) l &&
+    && all (`elem` capitals) l
-  all (`elem` (capitals ++ digits)) m && head r `elem` digits
+    && all (`elem` (capitals ++ digits)) m
+    && head r `elem` digits
   where
     [l, m, r] = bites [2, 9, 1] s
+luhn :: String -> Bool
 luhn x = 0 == rem (s1 + s2) 10
   where
     odds = [(: []), const []]
     evens = reverse odds
+    stream f =
-    stream f = concat $ zipWith ($) (cycle f) (stringInts $ reverse x)
+      concat $
+        zipWith
+          ($)
+          (cycle f)
+          (stringInts $ reverse x)
     s1 = sum (stream odds)
+    s2 =
-    s2 = sum $ sum . stringInts . show . (2 *) <$> stream evens
+      sum $
+        sum . stringInts . show
+          . (2 *) <$> stream evens
 charMap :: M.Map Char Int
-charMap = M.fromList $ zip (digits ++ capitals) [0 ..]
+charMap = M.fromList $ zip (digits <> capitals) [0 ..]
 stringInts :: String -> [Int]
@@ Line 1,516: / Line 1,531: @@
 bites ns xs =
   (reverse . fst) $
+    foldr
-  foldr (\x (a, r) -> first (: a) (splitAt x r)) ([], xs) (reverse ns)
+      (\x (a, r) -> first (: a) (splitAt x r))
+      ([], xs)
+      (reverse ns)
 capitals, digits :: String
 capitals = ['A' .. 'Z']
 digits = ['0' .. '9']
+--------------------------- TEST -------------------------
 main :: IO ()
 main =
   mapM_
     (print . ((,) <*> validISIN))
-    [ "US0378331005"
+    [ "US0378331005",
-    , "US0373831005"
+      "US0373831005",
-    , "U50378331005"
+      "U50378331005",
-    , "US03378331005"
+      "US03378331005",
-    , "AU0000XVGZA3"
+      "AU0000XVGZA3",
-    , "AU0000VXGZA3"
+      "AU0000VXGZA3",
-    , "FR0000988040"
+      "FR0000988040"
     ]</lang>
 {{Out}}