base62encode.hs

import qualified Data.DList as DL
import Control.Monad (forever)

base62Encode :: Integer -> String
base62Encode = map ((base62Alphabet!!) . fromIntegral) . DL.toList . digits
  where base62Alphabet = ['0'..'9'] ++ ['A'..'Z'] ++ ['a'..'z']
        digits n | n < 62    = DL.singleton n
                 | otherwise = digits (n `div` 62) `DL.snoc` (n `mod` 62)

readUuid :: String -> Integer
readUuid = read . ("0x"++) . filter (/='-')

main :: IO ()
main = forever $ fmap (base62Encode . readUuid) getLine >>= print