blob: ef76324994359a9dee75a9092b2a0f94aa8bebfa (
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
31
32
33
|
import System.Exit
import Control.Monad.Trans.State.Strict
eval :: Int -> State Int a -> a
eval p = fst . flip runState p
advance :: Int -> State Int ()
advance = modify' . (+)
loc :: State Int Int
loc = get
emit1 :: State Int ()
emit1 = advance 1
emitN :: Int -> State Int ()
-- adding in the 0 case, breaks with HEAD. 8.2.1 is fine with it.
-- emitN 0 = advance 0
emitN 0 = pure ()
emitN n = advance n
align8 :: State Int ()
align8 = do
bits <- (`mod` 8) <$> loc
emitN (8 - bits)
main :: IO ()
main = do
let p = eval 0 (emit1 >> align8 >> loc)
putStrLn $ show p
if p == 8
then putStrLn "OK" >> exitSuccess
else putStrLn "FAIL" >> exitFailure
|
