RosettaCodeData/Task/Forest-fire/Haskell/forest-fire.hs

60 lines
1.7 KiB
Haskell

import Control.Monad (replicateM, unless)
import Data.List (tails, transpose)
import System.Random (randomRIO)
data Cell
= Empty
| Tree
| Fire
deriving (Eq)
instance Show Cell where
show Empty = " "
show Tree = "T"
show Fire = "$"
randomCell :: IO Cell
randomCell = fmap ([Empty, Tree] !!) (randomRIO (0, 1) :: IO Int)
randomChance :: IO Double
randomChance = randomRIO (0, 1.0) :: IO Double
rim :: a -> [[a]] -> [[a]]
rim b = fmap (fb b) . (fb =<< rb)
where
fb = (.) <$> (:) <*> (flip (++) . return)
rb = fst . unzip . zip (repeat b) . head
take3x3 :: [[a]] -> [[[a]]]
take3x3 = concatMap (transpose . fmap take3) . take3
where
take3 = init . init . takeWhile (not . null) . fmap (take 3) . tails
list2Mat :: Int -> [a] -> [[a]]
list2Mat n = takeWhile (not . null) . fmap (take n) . iterate (drop n)
evolveForest :: Int -> Int -> Int -> IO ()
evolveForest m n k = do
let s = m * n
fs <- replicateM s randomCell
let nextState xs = do
ts <- replicateM s randomChance
vs <- replicateM s randomChance
let rv [r1, [l, c, r], r3] newTree fire
| c == Fire = Empty
| c == Tree && Fire `elem` concat [r1, [l, r], r3] = Fire
| c == Tree && 0.01 >= fire = Fire
| c == Empty && 0.1 >= newTree = Tree
| otherwise = c
return $ zipWith3 rv xs ts vs
evolve i xs =
unless (i > k) $
do let nfs = nextState $ take3x3 $ rim Empty $ list2Mat n xs
putStrLn ("\n>>>>>> " ++ show i ++ ":")
mapM_ (putStrLn . concatMap show) $ list2Mat n xs
nfs >>= evolve (i + 1)
evolve 1 fs
main :: IO ()
main = evolveForest 6 50 3