ROT13

rot13.fsx

module Encryption = 
	module private Helpers =
		let rec encrypt s = 
			match s with
			| [] -> []
			| h :: t -> ( char ((int h) + 13)) :: (encrypt t)
		
	let rot13 (s: string) = 
		let characters = s.ToCharArray ()
		let enc = characters |> List.ofArray |> Helpers.encrypt |> List.toArray
		new string(enc)
	
let text = "Hello"
let result = text |> Encryption.rot13
printfn "%s" result