September 2017 Update

Task/Non-decimal-radices-Convert/Haskell/non-decimal-radices-convert-4.hs

@@ -0,0 +1,52 @@
+import Data.List (unfoldr)
+import Data.Char (intToDigit)
+
+inBaseDigits :: [Char] -> Int -> String
+inBaseDigits ds n =
+  let base = length ds
+  in reverse $
+     unfoldr
+       (\x ->
+           (if x > 0
+              then let (d, r) = quotRem x base
+                   in Just (ds !! r, d)
+              else Nothing))
+       n
+
+inLowerHex :: Int -> String
+inLowerHex = inBaseDigits "0123456789abcdef"
+
+inUpperHex :: Int -> String
+inUpperHex = inBaseDigits "0123456789ABCDEF"
+
+inBinary :: Int -> String
+inBinary = inBaseDigits "01"
+
+inOctal :: Int -> String
+inOctal = inBaseDigits "01234567"
+
+inDevanagariDecimal :: Int -> String
+inDevanagariDecimal = inBaseDigits "०१२३४५६७८९"
+
+inHinduArabicDecimal :: Int -> String
+inHinduArabicDecimal = inBaseDigits "٠١٢٣٤٥٦٧٨٩"
+
+toBase :: Int -> Int -> String
+toBase intBase n =
+  if (intBase < 36) && (intBase > 0)
+    then inBaseDigits (take intBase (['0' .. '9'] ++ ['a' .. 'z'])) n
+    else []
+
+main :: IO ()
+main =
+  mapM_ putStrLn $
+  [ inLowerHex
+  , inUpperHex
+  , inBinary
+  , inOctal
+  , toBase 16
+  , toBase 2
+  , inDevanagariDecimal
+  , inHinduArabicDecimal
+  ] <*>
+  [254]