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-2.0.6.0	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.18	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.17	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.16	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.15	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.14	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.13	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.12	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.11	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.10	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.9	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.8	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.7	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.6	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.5	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.4	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.3	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.2	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.1	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs
trackler-2.0.5.0	tracks/haskell/exercises/simple-cipher/examples/success-standard/src/Cipher.hs