{-|
Module      : Data.Caesar
Description : Utilities for doing caesar transforms
Copyright   : (c) Mats Rauhala, 2019
License     : BSD3
Maintainer  : mats.rauhala@iki.fi
Stability   : experimental
Portability : POSIX

-}
module Data.Caesar where

-- | Type alias over char
type Caesar = Char

-- | Translate to the next character on the left
--
-- Has special handling for some symbols
next :: Char -> Char
next c =
  case c of
     '.' -> '.'
     ' ' -> ' '
     'ö' -> 'ä'
     'ä' -> 'å'
     'å' -> 'z'
     'a' -> 'ö'
     x   -> pred x

-- | Translate a character n times
caesar :: Int -> Caesar -> Caesar
caesar n x = foldr ($) x (replicate n next)