September 2017 Update

Task/Binary-digits/Haskell/binary-digits.hs

@@ -9,6 +9,14 @@ toBin n = showIntAtBase 2 ("01" !!) n ""
 toBin1 0 = []
 toBin1 x =  (toBin1 $ x `div` 2) ++ (show $ x `mod` 2)
 
+-- Or even more efficient (due to fusion) and universal implementation
+toBin2 = foldMap show . reverse . toBase 2
+
+toBase base = unfoldr modDiv
+  where modDiv 0 = Nothing
+        modDiv n = let (q, r) = (n `divMod` base) in Just (r, q)
+
+
 printToBin n = putStrLn $ printf "%4d  %14s  %14s" n (toBin n) (toBin1 n)
 
 main = do