blob: f3d8b76ca6c3930ded5096370927b271a0e7be76 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
module Main where
import Control.Monad (zipWithM)
import Data.List (elemIndex)
main :: IO ()
main = do
print $ toBase35 10
print $ toBase35 36
print $ fromBase35 "A"
print $ fromBase35 "11"
print $ fromBase35 "10"
base35Alphabet :: [Char]
base35Alphabet = ['0' .. '9'] ++ ['A' .. 'Y']
toBase35 :: Int -> String
toBase35 x = go "" x
where
go acc 0 = acc
go acc x = go (base35Alphabet !! (x `mod` 35) : acc) (x `div` 35)
fromBase35 :: [Char] -> Maybe Int
fromBase35 =
fmap sum
. zipWithM (\i c -> (*) (35 ^ i) <$> base35DigitToInt c) [0 ..]
. reverse
base35DigitToInt :: Char -> Maybe Int
base35DigitToInt c = elemIndex c base35Alphabet
|
