2D monadic loops

gistfile1.txt

module Main (main) where

import qualified Data.Vector.Unboxed.Mutable as VUM
import Control.Monad.State
import Control.Monad.Reader
import Control.Loop

main :: IO ()
main = do
    let w = 1024
        h = 1024
    v <- VUM.new $ w * h :: IO (VUM.IOVector Int)

    forM_ [0..1000] $ \_ -> do

        {-
        forM_ [0..h - 1] $ \py -> forM_ [0..w - 1] $ \px ->
            VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        {-
        forLoop 0 (< h) (+1) $ \py -> forLoop 0 (< w) (+1) $ \px ->
            VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        {-
        numLoop 0 (h - 1) $ \py -> numLoop 0 (w - 1) $ \px ->
            VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        return ()

    void $ flip runReaderT 0 . flip runStateT 0 . forM_ [0..100] $ \_ -> do

        {-
        forM_ [0..h - 1] $ \py -> forM_ [0..w - 1] $ \px ->
            liftIO $ VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        {-
        forLoop 0 (< h) (+1) $ \py -> forLoop 0 (< w) (+1) $ \px ->
            liftIO $ VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        {-
        numLoop 0 (h - 1) $ \py -> numLoop 0 (w - 1) $ \px ->
            liftIO $ VUM.unsafeWrite v (px + py * w) (px + py)
        -}

        return ()