Шифрование по цезарю

lab3/src/Lib.hs

@@ -1,6 +1,7 @@
 module Lib
     ( 
-        createAlphabetFromText
+        createAlphabetFromText,
+        encryptCaesar
     ) where
 
 createAlphabetFromText :: String -> [Char]
@@ -9,4 +10,15 @@ createAlphabetFromText (x:xs)
     | x `elem` alphabet = alphabet
     | otherwise     = x : alphabet
   where
-    alphabet = createAlphabetFromText xs
+    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)