Contents

module Cipher (caesarEncode, caesarDecode, caesarEncodeRandom) where

import Data.Char     (isAsciiLower)
import System.Random (newStdGen, randomRs)

caesarEncode, caesarDecode :: String -> String -> String
caesarEncode = caesar (+)
caesarDecode = caesar (-)

caesarEncodeRandom :: String -> IO (String, String)
caesarEncodeRandom xs = do
  g <- newStdGen
  let ks = take (length xs) (randomRs ('a', 'z') g)
  return (ks, caesarEncode ks xs)

caesar :: (Int -> Int -> Int) -> String -> String -> String
caesar op = zipWith rotate . cycle
  where
    rotate k x = if isAsciiLower k && isAsciiLower x
                then toAlpha (op (fromAlpha x) (fromAlpha k) `mod` 26)
                else x
    fromAlpha = subtract (fromEnum 'a') . fromEnum
    toAlpha = toEnum . (fromEnum 'a' +)

Version data entries

396 entries across 396 versions & 1 rubygems

Version	Path
trackler-2.2.1.180	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.179	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.178	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.177	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.176	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.175	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.174	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.173	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.172	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.171	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.170	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.169	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.167	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.166	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.165	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.164	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.163	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.162	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.161	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.2.1.160	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs