Last active
June 14, 2018 10:49
-
-
Save matsubara0507/d855acd68a7fd54005b7f04b104cd8e6 to your computer and use it in GitHub Desktop.
Brainf*ck in Haskell
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
import Data.Char (chr) | |
brainfuck :: String -> IO String | |
brainfuck cmds = loop ([], (return 0), (repeat $ return 0)) 0 [] | |
where | |
max = length cmds | |
loop :: ([IO Int], IO Int, [IO Int]) -> Int -> [IO Char] -> IO String | |
loop (xs,y,zs) index outs | |
| index == max = sequence (reverse outs) | |
| otherwise = cnd (cmds !! index) | |
where | |
cnd '>' = loop ((y:xs), (head zs), tail zs) (index+1) outs | |
cnd '<' = loop (tail xs, (head xs), (y:zs)) (index+1) outs | |
cnd '+' = loop (xs, (+ 1) <$> y, zs) (index+1) outs | |
cnd '-' = loop (xs, (+ (-1)) <$> y, zs) (index+1) outs | |
cnd '.' = loop (xs, y, zs) (index+1) ((chr <$> y):outs) | |
cnd ',' = loop (xs, read <$> getLine, zs) (index+1) outs | |
cnd '[' = let diff = serch '[' ']' (drop (index+1) cmds) in | |
do y' <- y | |
if y' == 0 then | |
loop (xs, y, zs) (index+diff+1) outs | |
else | |
loop (xs, y, zs) (index+1) outs | |
cnd ']' = let diff = serch ']' '[' (reverse $ take index cmds) in | |
do y' <- y | |
loop (xs, y, zs) (index-diff) outs | |
cnd _ = loop (xs, y, zs) (index+1) outs | |
serch :: Char -> Char -> [Char] -> Int | |
serch a b cmds = loop 1 0 cmds | |
where | |
loop 0 i _ = i | |
loop n i (l:ls) | |
| l == a = loop (n+1) (i+1) ls | |
| l == b = loop (n-1) (i+1) ls | |
| otherwise = loop n (i+1) ls | |
main = getContents >>= brainfuck . concat . lines >>= putStrLn |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
module Main where | |
import Data.Char (chr, ord) | |
import System.Environment (getArgs) | |
main :: IO () | |
main = do | |
[filepath] <- getArgs | |
prog <- readFile filepath | |
_ <- run $ initMachine prog | |
putStrLn "" | |
data Machine = | |
Machine { programOf :: Program, memOf :: Tape Int } deriving (Show) | |
data Tape a = Tape { front :: [a], current :: a, back :: [a] } deriving (Show) | |
type Program = Tape (Maybe Char) | |
mapCrr :: (a -> a) -> Tape a -> Tape a | |
mapCrr f tape = tape { current = f (current tape) } | |
moveFront :: Tape a -> Tape a | |
moveFront (Tape [] _ _) = error "front is empty." | |
moveFront (Tape f c b) = Tape (tail f) (head f) (c : b) | |
moveBack :: a -> Tape a -> Tape a | |
moveBack a (Tape f c []) = Tape (c : f) a [] | |
moveBack _ (Tape f c b) = Tape (c : f) (head b) (tail b) | |
initMachine :: String -> Machine | |
initMachine = initMachine' . flip mappend [fin] . fmap Just | |
where | |
initMachine' s = Machine (Tape [] (head s) (tail s)) (Tape [] 0 []) | |
fin :: Maybe Char | |
fin = Nothing | |
run :: Machine -> IO Machine | |
run = loopM run' ((/=) fin . current . programOf) | |
loopM :: Monad m => (a -> m a) -> (a -> Bool) -> a -> m a | |
loopM f p a = if p a then f a >>= loopM f p else return a | |
run' :: Machine -> IO Machine | |
run' m@(Machine prog mem) = | |
(\m' -> m' { programOf = moveBack' $ programOf m' }) <$> cond (current prog) | |
where | |
cond (Just '>') = return $ Machine prog (moveBack 0 mem) | |
cond (Just '<') = return $ Machine prog (moveFront mem) | |
cond (Just '+') = return $ Machine prog (mapCrr (+ 1) mem) | |
cond (Just '-') = return $ Machine prog (mapCrr (+ (-1)) mem) | |
cond (Just '.') = return m <* putChar (chr $ current mem) | |
cond (Just ',') = | |
(\c -> Machine prog (mapCrr (const $ ord c) mem)) <$> getChar | |
cond (Just '[') = return . flip Machine mem $ | |
(if current mem == 0 then jump ('[', ']') moveBack' else id) prog | |
cond (Just ']') = return . flip Machine mem $ | |
(if current mem /= 0 then jump (']', '[') moveFront else id) prog | |
cond _ = return m | |
moveBack' = moveBack fin | |
jump :: (Char, Char) -> (Program -> Program) -> Program -> Program | |
jump (a, b) f = go 1 | |
where | |
go 0 prog = prog | |
go n prog = go (updateCounter (p a) (p b) (current $ f prog) n) (f prog) | |
p x = (==) (Just x) | |
updateCounter :: (a -> Bool) -> (a -> Bool) -> a -> Int -> Int | |
updateCounter p q a = (+) (if p a then 1 else if q a then -1 else 0) |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
+++++++++[>++++++++>+++++++++++>+++++<<<-]>.>++.+++++++..+++.>-. | |
------------.<++++++++.--------.+++.------.--------.>+. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment