Data commit

Task/SEDOLs/Haskell/sedols.hs

@@ -0,0 +1,49 @@
+import Data.Char (isAsciiUpper, isDigit, ord)
+
+-------------------------- SEDOLS ------------------------
+
+checkSum :: String -> String
+checkSum x =
+  case traverse sedolValue x of
+    Right xs -> (show . checkSumFromSedolValues) xs
+    Left annotated -> annotated
+
+checkSumFromSedolValues :: [Int] -> Int
+checkSumFromSedolValues xs =
+  rem
+    ( 10
+        - rem
+          ( sum $
+              zipWith
+                (*)
+                [1, 3, 1, 7, 3, 9]
+                xs
+          )
+          10
+    )
+    10
+
+sedolValue :: Char -> Either String Int
+sedolValue c
+  | c `elem` "AEIOU" = Left " ← Unexpected vowel."
+  | isDigit c = Right (ord c - ord '0')
+  | isAsciiUpper c = Right (ord c - ord 'A' + 10)
+
+--------------------------- TEST -------------------------
+main :: IO ()
+main =
+  mapM_
+    (putStrLn . ((<>) <*> checkSum))
+    [ "710889",
+      "B0YBKJ",
+      "406566",
+      "B0YBLH",
+      "228276",
+      "B0YBKL",
+      "557910",
+      "B0YBKR",
+      "585284",
+      "B0YBKT",
+      "BOYBKT", -- Ill formed test case - illegal vowel.
+      "B00030"
+    ]