PrimVar vs IORef vs Parameters

results.md

PrimVar:

1:

real    0m39.444s
user    0m39.348s
sys     0m0.058s

2:

real    0m39.715s
user    0m39.621s
sys     0m0.056s

3:

real    0m40.055s
user    0m39.964s
sys     0m0.039s

Code

runBrainfuck :: Brainfuck -> IO ()
runBrainfuck bf = do
  dataPointer <- newPrimVar (0 :: Word16)
  arr <- MV.replicate @_ @Word8 (fromIntegral (maxBound @Word16) + 1) 0

  let readRef = fromIntegral <$> readPrimVar dataPointer
      modifyRef = modifyPrimVar dataPointer

  bf & fix \evalLoop bf' ->
    forM_ bf' \case
      Op OpInc    -> readRef >>= MV.modify arr (+ 1)
      Op OpDec    -> readRef >>= MV.modify arr (- 1)
      Op OpLeft   -> modifyRef (- 1)
      Op OpRight  -> modifyRef (+ 1)
      Op OpOutput -> readRef >>= MV.read arr >>= putChar . w2c
      Op OpInput  -> join $ liftM2 (MV.write arr) readRef (c2w <$> getChar)
      Loop bf''   -> fix \recurse -> do
        state <- readRef >>= MV.read arr
        unless (state == 0) (evalLoop bf'' >> recurse)

  putChar '\n'

IORef

1:

real    1m27.346s
user    1m27.183s
sys     0m0.096s

2:

real    1m27.948s
user    1m27.702s
sys     0m0.117s

3: TL, didn't wait

Code

runBrainfuck :: Brainfuck -> IO ()
runBrainfuck bf = do
  dataPointer <- newIORef (0 :: Word16)
  arr <- MV.replicate @_ @Word8 (fromIntegral (maxBound @Word16) + 1) 0

  let readRef = fromIntegral <$> readIORef dataPointer
      modifyRef = modifyIORef dataPointer

  bf & fix \evalLoop bf' ->
    forM_ bf' \case
      Op OpInc    -> readRef >>= MV.modify arr (+ 1)
      Op OpDec    -> readRef >>= MV.modify arr (- 1)
      Op OpLeft   -> modifyRef (- 1)
      Op OpRight  -> modifyRef (+ 1)
      Op OpOutput -> readRef >>= MV.read arr >>= putChar . w2c
      Op OpInput  -> join $ liftM2 (MV.write arr) readRef (c2w <$> getChar)
      Loop bf''   -> fix \recurse -> do
        state <- readRef >>= MV.read arr
        unless (state == 0) (evalLoop bf'' >> recurse)

  putChar '\n'

Parameters

1:

real    0m50.884s
user    0m50.846s
sys     0m0.040s

2:

real    0m52.145s
user    0m52.083s
sys     0m0.048s

3:

real    0m51.155s
user    0m51.108s
sys     0m0.046s

Code

runBrainfuck :: Brainfuck -> IO ()
runBrainfuck bf = do
  arr <- MV.replicate @_ @Word8 (fromIntegral (maxBound @Word16) + 1) 0

  let dataPointer = (0 :: Word16)
      w2i = fromIntegral

      evalLoop :: Word16 -> Brainfuck -> IO Word16
      evalLoop !dp = \case
        []             -> return dp
        Op OpInc:xs    -> MV.modify arr (+ 1) (w2i dp) >> evalLoop dp xs
        Op OpDec:xs    -> MV.modify arr (- 1) (w2i dp) >> evalLoop dp xs
        Op OpLeft:xs   -> evalLoop (dp - 1) xs
        Op OpRight:xs  -> evalLoop (dp + 1) xs
        Op OpOutput:xs -> MV.read arr (w2i dp) >>= putChar . w2c >> evalLoop dp xs
        Op OpInput:xs  -> (MV.write arr (w2i dp) . c2w =<< getChar) >> evalLoop dp xs
        Loop bf'':xs   -> let loop !dp' = do
                                state <- MV.read arr (w2i dp')
                                if state /= 0 then evalLoop dp' bf'' >>= loop else evalLoop dp' xs
                          in loop dp

  evalLoop dataPointer bf

  putChar '\n'