haskell-mm, Haskell

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module Main (main) where

main :: IO ()
main = do
  machine (Run 0 Process 1 [0, 0, 0, 0])
  putStrLn "----------------------------------------------------------------"
  machine (Run 9 Process 4 [3, 3, 14, 1])
  putStrLn "----------------------------------------------------------------"

----------------------------------------------------------------

data CmdType = Process | Decision deriving (Show)
type CmdAddr = Int
type Counter = Int
type Memory  = [Int]

data State
  = Run Counter CmdType CmdAddr Memory
  | Stop
  | Fail String

instance Show State where
  show Stop = "stop"
  show (Fail err) = "failure: " ++ err

show (Run c Process i cells) =
    "Step: " ++ align2 c ++ "    Proc: " ++ show i ++ "   " ++ showCells cells
    where
      showCells []          = ""
      showCells (cell:rest) = " " ++ align2 cell ++ showCells rest
      align2 n
        | n < 10     =  " " ++ show n
        | otherwise  =  show n

show (Run c t i cells) = "Step " ++ show c ++ " " ++ show t ++ " " ++ show i ++ " " ++ show cells

----------------------------------------------------------------

cpu :: State -> State

cpu (Run c Process 1 [c0, c1, c2, c3]) = Run (c+1) Decision 1 [c0+1, c1, c2, c3]

cpu (Run c Decision 1 cells)
  | even (sum cells)  =  Run c Process 4 cells
  | otherwise         =  Run c Process 3 cells

cpu (Run c Process 2 [c0, c1, c2, c3]) = Run (c+1) Decision 2 [c0, c1+c3+1, c2, c3]

cpu (Run c Decision 2 cells)
  | sum cells `mod` 7 > 0  =  Run c Process 3 cells
  | otherwise              =  Run c Process 4 cells

cpu (Run c Process 3 [c0, c1, c2, c3])
  | (c0+c1) `mod` 3 /= 0  =  Run (c+1) Decision 3 [c0, c1, c2+7, c3]
  | otherwise             =  Run (c+1) Decision 3 [c0, c1, c2,   c3]

cpu (Run c Decision 3 cells)
  | all even cells  =  Run c Process 2 cells
  | otherwise       =  Run c Process 1 cells

cpu (Run c Process 4 [c0, c1, c2, c3])
  | (c0+c2) `mod` 5 /= 4  =  Run (c+1) Decision 4 [c0, c1, c2, c3+1]
  | otherwise             =  Run (c+1) Decision 4 [c0, c1, c2, c3]

cpu (Run c Decision 4 cells)
  | sum cells > 24  =  Run c Process 5 cells
  | otherwise       =  Run c Process 2 cells

cpu (Run _ Process 5 _) = Stop

cpu Stop       = Stop
cpu (Fail err) = Fail err
cpu state      = Fail (show state)

----------------------------------------------------------------

machine :: State -> IO ()
machine Stop                  = return ()
machine s@(Fail _)            = print s
machine s@(Run _ Process _ _) = print s >> machine (cpu s)
machine s                     = machine (cpu s)

Show compiler warnings [ + ] Compiler args [ + ] Show input
Compilation time: 1.02 sec, absolute running time: 0.16 sec, cpu time: 0.01 sec, memory peak: 5 Mb, absolute service time: 1,2 sec