Multiplication tables: Difference between revisions

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@@ Line 3,517: / Line 3,517: @@
 =={{header|Haskell}}==
 <lang haskell>import Data.Maybe (fromMaybe, maybe)
-import Data.Bool (bool)
+------------------- MULTIPLICATION TABLE -----------------
-table :: [Int] -> [[Maybe Int]]
-table xs =
+mulTable :: [Int] -> [[Maybe Int]]
+mulTable xs =
   (Nothing : axis) :
   zipWith
     (:)
     axis
-    [ [ bool (Just (x * y)) Nothing (x > y)
+    [[upperMul x y | y <- xs] | x <- xs]
-      | y <- xs ]
-    | x <- xs ]
   where
     axis = Just <$> xs
+    upperMul x y
+      | x > y = Nothing
+      | otherwise = Just (x * y)
---------------------------- TEST ---------------------------
+--------------------------- TEST -------------------------
 main :: IO ()
 main =
   (putStrLn . unlines) $
+    showTable . mulTable
-  showTable . table <$> [[13 .. 20], [1 .. 12], [95 .. 100]]
+      <$> [ [13 .. 20],
+            [1 .. 12],
+            [95 .. 100]
+          ]
------------------------- FORMATTING ------------------------
+------------------------ FORMATTING ----------------------
 showTable :: [[Maybe Int]] -> String
 showTable xs = unlines $ head rows : [] : tail rows
@@ Line 3,544: / Line 3,551: @@
     gap = replicate w ' '
     rows = (maybe gap (rjust w ' ' . show) =<<) <$> xs
+    rjust n c = (drop . length) <*> (replicate n c <>)</lang>
-rjust :: Int -> Char -> String -> String
-rjust n c = (drop . length) <*> (replicate n c ++)</lang>
 {{Out}}
 <pre>      13  14  15  16  17  18  19  20