CODEWITHSUNDEEP
haskellencryption
Eddie
Eddie

Reputation: 891

Making my own data type "Cipher" in Haskell

I am trying to make my own data type called "Cipher" in Haskell. I have realised that there are 26! values the type can take (any combination of chars in the alphabet used once and only once).

I have started it like this:

data Cipher = ['a'..'z'] |

I know Haskell can "guess" combinations, but how can I tell it I want the type to be able to take any of the values as stated above?

Upvotes: 0

Views: 344

Answers (1)

daniel gratzer
daniel gratzer

Reputation: 53901

A simple answer might be

import Data.Char (ord)
import Data.List (permutations)
newtype Cipher = Cipher String

ciphers = map Cipher . permutations $ ['a' .. 'z']

-- Lookup a characters value in the cipher
mapChar :: Cipher -> Char -> Char
mapChar ciph c = ciph !! ord c - ord 'a'

encode :: Cipher -> String -> String
encode ciph = map (mapChar ciph)

decode :: Cipher -> String -> String
decode -- Ill let you figure this out

Upvotes: 1

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