tweak newRandomBoard

src/Types/GameBoard.hs

@@ -9,6 +9,7 @@ module Types.GameBoard where
 import Data.Array
 import Data.Binary.Builder (append)
 import Data.Maybe (mapMaybe)
+import Data.Tuple.Extra
 import Display (Display, display)
 import System.Random.Stateful (RandomGen)
 import Types.BoardPosition
@@ -34,21 +35,17 @@ select :: (GameMode mode) => BoardPosition -> BoardPosition -> GameBoard mode ->
 select topLeft bottomRight MkGameBoard{board} =
     mapMaybe (board !) (range (topLeft, bottomRight))
 
--- TODO: rewrite this with monadic RNG
-newRandomBoard :: (RandomGen g, GameMode mode) => g -> mode -> Int -> Int -> (GameBoard mode, g)
-newRandomBoard rng gameMode width height =
-    (MkGameBoard{width, height, gameMode, board = array (low, high) cellAssocList}, nextRng)
+-- TODO: rewrite this with monadic RNG?
+newRandomBoard :: (RandomGen g, GameMode mode) => mode -> Int -> Int -> g -> (GameBoard mode, g)
+newRandomBoard gameMode width height rng =
+    (MkGameBoard{width, height, gameMode, board = array ixRange cellAssocList}, nextRng)
   where
-    low = (0, 0)
-    high = (width - 1, height - 1)
+    ixRange = ((0, 0), (width - 1, height - 1))
     (cellAssocList, nextRng) =
         foldl'
-            ( \(cur, rng') -> \ix ->
-                let (res, next) = gen gameMode rng' in ((ix, Just res) : cur, next)
-            )
+            (\(cur, rng') -> \ix -> first ((: cur) . (ix,) . Just) (gen gameMode rng'))
             ([], rng)
-            ixs
-    ixs = range (low, high)
+            (range ixRange)
 
 instance (Display (Tile mode)) => Display (GameBoard mode) where
     display MkGameBoard{width, height, board} =