Шифрование по цезарю

lab3/app/Main.hs

@@ -2,8 +2,13 @@ module Main (main) where
 
 import Lib
 
+caesarShift :: Int
+caesarShift = 66
+
 main :: IO ()
 main = do
     inputText <- readFile "resources/biography.txt"
     putStrLn $ take 30 inputText
-    putStrLn $ createAlphabetFromText inputText
+    let alphabet = createAlphabetFromText inputText
+    putStrLn $ show (length alphabet)
+    putStrLn $ take 30 (encryptCaesar alphabet caesarShift inputText)

lab3/src/Lib.hs

@@ -1,6 +1,7 @@
 module Lib
     ( 
-        createAlphabetFromText
+        createAlphabetFromText,
+        encryptCaesar
     ) where
 
 createAlphabetFromText :: String -> [Char]
@@ -10,3 +11,14 @@ createAlphabetFromText (x:xs)
     | otherwise     = x : alphabet
   where
     alphabet = createAlphabetFromText xs
+
+indexOf :: (Eq t) => [t] -> t -> Int
+indexOf [] _ = -1
+indexOf (x : xs) target
+  | x == target = 0
+  | otherwise = 1 + indexOf xs target
+
+encryptCaesar :: [Char] -> Int -> String -> String
+encryptCaesar alphabet shift text = map caesarChar text
+  where
+    caesarChar c = alphabet !! ((indexOf alphabet c + shift) `mod` length alphabet)