Rewritten loops and update tape operations
This commit is contained in:
Claudio Maggioni (maggicl)
parent
df9ac7f41c
commit
4dc1eeb3c3
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@ -23,13 +23,11 @@ newtype Byte = Byte Int deriving (Eq, Ord, Read, Show)
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chr :: Byte -> Char
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chr (Byte i) = toEnum i :: Char
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incr :: Byte -> Byte
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incr (Byte 255) = Byte 0
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incr (Byte i) = Byte (i + 1)
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decr :: Byte -> Byte
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decr (Byte 0) = Byte 255
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decr (Byte i) = Byte (i - 1)
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updateCell :: Instruction -> Byte -> Byte
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updateCell Add (Byte 255) = Byte 0
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updateCell Sub (Byte 0) = Byte 255
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updateCell Add (Byte i) = Byte (i + 1)
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updateCell Sub (Byte i) = Byte (i - 1)
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type Tape = [Byte]
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type Program = [Instruction]
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@ -55,7 +53,7 @@ instance Applicative Execution where
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pure = return
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(<*>) = ap
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toProgram :: String -> [Instruction]
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toProgram :: String -> Program
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toProgram s = catMaybes $ fmap parseInstr s
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tapeHelp :: Tape -> Int -> (Byte -> Byte) -> Tape
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@ -71,61 +69,58 @@ errorDesc LoopNoMatch = "ERROR: '[' or ']' not working. Matching parenthesis not
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incrIP :: State -> State
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incrIP p = p { ip = ip p + 1 }
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execAdd :: State -> Execution State
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execAdd p = Working p { tape = newTape }
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where newTape = tapeHelp (tape p) (dp p) incr
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execSub :: State -> Execution State
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execSub p = Working p { tape = newTape }
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where newTape = tapeHelp (tape p) (dp p) decr
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execUpdate :: Instruction -> State -> Execution State
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execUpdate i p = Working p { tape = newTape }
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where newTape = tapeHelp (tape p) (dp p) (updateCell i)
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execTapeLeft :: State -> Execution State
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execTapeLeft p = case dp p of 0 -> Crash NegTape
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n -> Working p { dp = n - 1 }
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execTapeRight :: State -> Execution State
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execTapeRight p = Working p { tape = if endOfType then tape p ++ [Byte 0] else tape p, dp = dp p + 1 }
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where endOfType = dp p == length (tape p) - 1
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execTapeRight p = Working p { tape = tape p ++ newTape, dp = dp p + 1 }
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where newTape = case dp p == length (tape p) - 1 of True -> [Byte 0]
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_ -> []
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execOut :: State -> Execution State
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execOut p = Working p { output = output p ++ [chr char]}
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where char = tape p !! dp p
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data WalkingDirection = Forward | Backward deriving (Eq, Show)
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findMatching :: Program -> Instruction -> Int -> Maybe Int
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findMatching prg toFind = fmHelper $ -1
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where (oppos, limit, next) = case toFind of
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LoopEnd -> (LoopStart, length prg, (+1))
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LoopStart -> (LoopEnd, 0, (-1+))
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findMatching :: Program -> Int -> WalkingDirection -> Maybe Int
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findMatching prg start wd = case wd of
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Forward -> fmHelper start (-1) LoopEnd LoopStart (+1) (length prg)
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Backward -> fmHelper start (-1) LoopStart LoopEnd (-1+) 0
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where fmHelper :: Int -> Int -> Instruction -> Instruction -> (Int -> Int)
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-> Int -> Maybe Int
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fmHelper s acc b ob upd limit
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| s == limit = Nothing
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| acc == 0 && c == b = Just s
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| c == b = fmHelper (upd s) (acc - 1) b ob upd limit
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| c == ob = fmHelper (upd s) (acc + 1) b ob upd limit
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| otherwise = fmHelper (upd s) acc b ob upd limit
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fmHelper :: Int -> Int -> Maybe Int
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fmHelper acc s
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| s == limit = Nothing
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| acc == 0 && c == toFind = Just s
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| c == toFind = fmHelper (acc - 1) $ next s
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| c == oppos = fmHelper (acc + 1) $ next s
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| otherwise = fmHelper acc $ next s
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where c = prg !! s
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execLoop :: WalkingDirection -> State -> Execution State
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execLoop d w = case posOrF of
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Just n -> Working w { ip = n }
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Nothing -> Crash LoopNoMatch
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where jump
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| (tape w !! dp w) == Byte 0 = d == Forward
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| otherwise = d == Backward
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posOrF = if jump then findMatching (program w) (ip w) d else Just $ ip w
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execLoop :: Instruction -> State -> Execution State
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execLoop d w = case posOrF of Just n -> Working w { ip = n }
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Nothing -> Crash LoopNoMatch
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where isZero = (tape w !! dp w) == Byte 0
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jump = case d of LoopStart -> isZero
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LoopEnd -> not isZero
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posOrF = case jump of True -> findMatching (program w) d (ip w)
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_ -> Just $ ip w
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execute :: State -> Execution State
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execute w = (traceShowId $ runInstr w) >>= checkDone >>= execute
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execute w = do ran <- (traceShowId $ runInstr w)
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newStatus <- checkDone ran
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execute newStatus
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where instrFor w = case (program w !! ip w) of
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TapeLeft -> execTapeLeft
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TapeRight -> execTapeRight
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Add -> execAdd
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Sub -> execSub
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Out -> execOut
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LoopStart -> execLoop Forward
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LoopEnd -> execLoop Backward
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TapeLeft -> execTapeLeft
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TapeRight -> execTapeRight
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Add -> execUpdate Add
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Sub -> execUpdate Sub
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Out -> execOut
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l -> execLoop l
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runInstr :: State -> Execution State
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runInstr w = instrFor w $ w
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