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exercises/secret-lang/Secret-lang.hs

@@ -1,32 +1,58 @@
 import Data.Char(toLower)
 
+vowels = "aeiou"
 
 isChar :: Char -> Bool
-isChar = undefined
+isChar char 
+	| toLower char >= 'a' && toLower char <= 'z' = True
+isChar _ = False
+
+isInString :: Char -> String -> Bool
+isInString char [] = False
+isInString char (first:rest)
+	| char == first = True
+	| char /= first = isInString char rest
 
 
 isVowel :: Char -> Bool
-isVowel = undefined
+isVowel char
+	| isInString (toLower char) vowels == True = True
+isVowel _ = False
 
 
 isConsonant :: Char -> Bool
-isConsonant = undefined
+isConsonant char
+	| isVowel char == False && isChar char == True = True
+	| otherwise = False
 
 
 encode :: String -> String
-encode = undefined
+encode [] = []
+encode (first:rest)
+	| isConsonant first == True = first : 'o' : first : (encode rest)
+	| otherwise = first:(encode rest)
 
 
 -- Bonus #1
 encode' :: String -> String
-encode' = undefined
+encode' [] = []
+encode' (first:rest)
+	| isConsonant first == True = first : 'o' : toLower first : (encode' rest)
+	| otherwise = first:(encode' rest)
 
 
 -- Bonus #2
 dropN :: Int -> String -> String
-dropN = undefined
+dropN number [] = []
+dropN 0 string = string
+dropN number (first:rest) = dropN (number-1) rest
+
 
 
 --Assume we'll be decoding only valid words
 decode :: String -> String
-decode = undefined
+decode [] = []
+decode (x : 'o' : y : rest)
+	| x == y = x : decode (dropN 2 ('o':y:rest))
+	| otherwise = x : 'o' : y : (decode (rest))
+decode (first : rest) = first : decode (rest)