September Morn Update

Task/SEDOLs/JavaScript/sedols-2.js

@@ -0,0 +1,164 @@
+(() => {
+    'use strict';
+
+    const main = () => {
+
+        // checkSumLR :: String -> Either String String
+        const checkSumLR = s => {
+            const
+                tpl = partitionEithers(map(charValueLR, s));
+            return 0 < tpl[0].length ? (
+                Left(s + ' -> ' + unwords(tpl[0]))
+            ) : Right(rem(10 - rem(
+                sum(zipWith(
+                    (a, b) => a * b,
+                    [1, 3, 1, 7, 3, 9],
+                    tpl[1]
+                )), 10
+            ), 10).toString());
+        };
+
+        // charValue :: Char -> Either String Int
+        const charValueLR = c =>
+            isAlpha(c) ? (
+                isUpper(c) ? (
+                    elem(c, 'AEIOU') ? Left(
+                        'Unexpected vowel: ' + c
+                    ) : Right(ord(c) - ord('A') + 10)
+                ) : Left('Unexpected lower case character: ' + c)
+            ) : isDigit(c) ? Right(
+                parseInt(c, 10)
+            ) : Left('Unexpected character: ' + c);
+
+        // TESTS ------------------------------------------
+        const [problems, checks] = Array.from(
+            partitionEithers(map(s => bindLR(
+                    checkSumLR(s),
+                    c => Right(s + c)
+                ),
+                [
+                    "710889", "B0YBKJ", "406566",
+                    "B0YBLH", "228276", "B0YBKL",
+                    "557910", "B0YBKR", "585284",
+                    "B0YBKT", "B00030"
+                ]
+            ))
+        );
+        return unlines(
+            0 < problems.length ? (
+                problems
+            ) : checks
+        );
+    };
+
+    // GENERIC FUNCTIONS ----------------------------
+
+    // Left :: a -> Either a b
+    const Left = x => ({
+        type: 'Either',
+        Left: x
+    });
+
+    // Right :: b -> Either a b
+    const Right = x => ({
+        type: 'Either',
+        Right: x
+    });
+
+    // Tuple (,) :: a -> b -> (a, b)
+    const Tuple = (a, b) => ({
+        type: 'Tuple',
+        '0': a,
+        '1': b,
+        length: 2
+    });
+
+    // bindLR (>>=) :: Either a -> (a -> Either b) -> Either b
+    const bindLR = (m, mf) =>
+        undefined !== m.Left ? (
+            m
+        ) : mf(m.Right);
+
+    // elem :: Eq a => a -> [a] -> Bool
+    const elem = (x, xs) => xs.includes(x);
+
+    // isAlpha :: Char -> Bool
+    const isAlpha = c =>
+        /[A-Za-z\u00C0-\u00FF]/.test(c);
+
+    // isDigit :: Char -> Bool
+    const isDigit = c => {
+        const n = ord(c);
+        return 48 <= n && 57 >= n;
+    };
+
+    // isUpper :: Char -> Bool
+    const isUpper = c =>
+        /[A-Z]/.test(c);
+
+    // Returns Infinity over objects without finite length.
+    // This enables zip and zipWith to choose the shorter
+    // argument when one is non-finite, like cycle, repeat etc
+
+    // length :: [a] -> Int
+    const length = xs =>
+        (Array.isArray(xs) || 'string' === typeof xs) ? (
+            xs.length
+        ) : Infinity;
+
+    // map :: (a -> b) -> [a] -> [b]
+    const map = (f, xs) =>
+        (Array.isArray(xs) ? (
+            xs
+        ) : xs.split('')).map(f);
+
+    // ord :: Char -> Int
+    const ord = c => c.codePointAt(0);
+
+    // partitionEithers :: [Either a b] -> ([a],[b])
+    const partitionEithers = xs =>
+        xs.reduce(
+            (a, x) => undefined !== x.Left ? (
+                Tuple(a[0].concat(x.Left), a[1])
+            ) : Tuple(a[0], a[1].concat(x.Right)),
+            Tuple([], [])
+        );
+
+    // rem :: Int -> Int -> Int
+    const rem = (n, m) => n % m;
+
+    // sum :: [Num] -> Num
+    const sum = xs => xs.reduce((a, x) => a + x, 0);
+
+    // take :: Int -> [a] -> [a]
+    // take :: Int -> String -> String
+    const take = (n, xs) =>
+        'GeneratorFunction' !== xs.constructor.constructor.name ? (
+            xs.slice(0, n)
+        ) : [].concat.apply([], Array.from({
+            length: n
+        }, () => {
+            const x = xs.next();
+            return x.done ? [] : [x.value];
+        }));
+
+    // unlines :: [String] -> String
+    const unlines = xs => xs.join('\n');
+
+    // unwords :: [String] -> String
+    const unwords = xs => xs.join(' ');
+
+    // zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
+    const zipWith = (f, xs, ys) => {
+        const
+            lng = Math.min(length(xs), length(ys)),
+            as = take(lng, xs),
+            bs = take(lng, ys);
+        return Array.from({
+            length: lng
+        }, (_, i) => f(as[i], bs[i], i));
+    };
+
+    // MAIN ---
+    return main();
+})();