[Haskell-cafe] Solitaire cipher

[jim burton]

Chris Kuklewicz wrote:
> 
> There are several problems with the behavior:
> 
>> *Main> encrypt ""
>> "XXXXX "
>> *Main> decrypt $ encrypt ""
>> "TANZP XXXXX "
> 
> So fixing this case would be the first thing to do, followed by:
> 
>> *Main> encrypt "hello"
>> "LBVJW XXXXX "
>> *Main> decrypt $ encrypt "hello"
>> "HELLO YFRTQ XXXXX "
> 
> 

Thanks a lot, I think these are all related...some changes

in_fives l = trim $ foldr (\x y -> x++" "++y) [] $ unfoldr (splitAtMb 5)
             (l ++ replicate n 'X') 
             where n = if m5 == 0 then 0 else 5 - m5
                   m5 = length l `mod` 5

trim :: String -> String
trim = reverse . dropWhile isSpace . reverse . dropWhile isSpace

process :: (Int -> Int -> Int) -> String -> String
process f s = if null str1 then "" else in_fives $ map int2alpha $ zipWith f
ints1 ints2
    where str1  = trim $ clean s
          str2  = take (length str1) (keystream newdeck)
          ints1 = map char2int str1
          ints2 = map char2int str2

*Main> decrypt $ encrypt $ decrypt $ encrypt "hello"
"HELLO"
*Main> decrypt $ encrypt $ decrypt $ encrypt "haskell is miles better"
"HASKE LLISM ILESB ETTER"
*Main> 

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