Cartesian product of two or more lists: Difference between revisions

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@@ Line 1,092: / Line 1,092: @@
 For the Cartesian product of just two lists:
 <lang JavaScript>(() => {
     // CARTESIAN PRODUCT OF TWO LISTS -----------------------------------------
     // cartProd :: [a] -> [b] -> [[a, b]]
-    const cartProd = (xs, ys) =>
+    const cartProd = xs => ys =>
-        concatMap((x => concatMap(y => [
+        xs.flatMap(x => ys.map(y => [x, y]))
-            [x, y]
-        ], ys)), xs);
-    // GENERIC FUNCTIONS ------------------------------------------------------
-    // concatMap :: (a -> [b]) -> [a] -> [b]
-    const concatMap = (f, xs) => [].concat.apply([], xs.map(f));
-    // map :: (a -> b) -> [a] -> [b]
-    const map = (f, xs) => xs.map(f);
-    // show :: a -> String
-    const show = x => JSON.stringify(x); //, null, 2);
-    // unlines :: [String] -> String
-    const unlines = xs => xs.join('\n');
     // TEST -------------------------------------------------------------------
-    return unlines(map(show, [
+    return [
-        cartProd([1, 2], [3, 4]),
+        cartProd([1, 2])([3, 4]),
-        cartProd([3, 4], [1, 2]),
+        cartProd([3, 4])([1, 2]),
-        cartProd([1, 2], []),
+        cartProd([1, 2])([]),
-        cartProd([], [1, 2]),
+        cartProd([])([1, 2]),
-    ]));
+    ].map(JSON.stringify).join('\n');
 })();</lang>
 {{Out}}