Dot product: Difference between revisions

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@@ Line 1,593: / Line 1,593: @@
 <syntaxhighlight lang="javascript">(() => {
-    'use strict';
+    "use strict";
+    // ------------------- DOT PRODUCT -------------------
     // dotProduct :: [Int] -> [Int] -> Int
-    const dotProduct = (xs, ys) => {
+    const dotProduct = xs =>
-        const sum = xs => xs ? xs.reduce((a, b) => a + b, 0) : undefined;
+        ys => xs.length === ys.length
+            ? sum(zipWith(mul)(xs)(ys))
+            : undefined;
+    // ---------------------- TEST -----------------------
+    // main :: IO ()
+    const main = () =>
+        dotProduct([1, 3, -5])([4, -2, -1]);
+    // --------------------- GENERIC ---------------------
+    // mul :: Num -> Num -> Num
+    const mul = x =>
+        y => x * y;
+    // sum :: [Num] -> Num
+    const sum = xs =>
+    // The numeric sum of all values in xs.
+        xs.reduce((a, x) => a + x, 0);
-        return xs.length === ys.length ? (
-            sum(zipWith((a, b) => a * b, xs, ys))
-        ) : undefined;
-    }
     // zipWith :: (a -> b -> c) -> [a] -> [b] -> [c]
-    const zipWith = (f, xs, ys) => {
+    const zipWith = f =>
+    // A list constructed by zipping with a
-        const ny = ys.length;
+    // custom function, rather than with the
-        return (xs.length <= ny ? xs : xs.slice(0, ny))
+    // default tuple constructor.
-            .map((x, i) => f(x, ys[i]));
+        xs => ys => xs.map(
-    }
+            (x, i) => f(x)(ys[i])
+        ).slice(
+, Math.min(xs.length, ys.length)
+        );
+    // MAIN ---
-    return dotProduct([1, 3, -5], [4, -2, -1]);
+    return main();
 })();</syntaxhighlight>
-{{Out}}
-<syntaxhighlight lang="javascript">3</syntaxhighlight>
 =={{header|jq}}==