Move matrix stuff

Matrix.hs

@@ -0,0 +1,25 @@
+module Matrix where
+
+data Mat a = Mat [[a]]
+type Pos  = (Int, Int)
+
+instance Functor Mat where
+  fmap f (Mat m) = Mat ((map . map) f m)
+
+-- | Safely access a list
+-- [4,1,5,9] ?? 2 == Just 5
+-- [5,7] ?? 3 == Nothing
+(??) :: [a] -> Int -> Maybe a
+xs     ?? n | n < 0 =  Nothing
+[]     ?? _         =  Nothing
+(x:_)  ?? 0         =  Just x
+(_:xs) ?? n         =  xs ?? (n-1)
+
+-- | Create a matrix of indeces of a matrix
+indeces :: Mat a -> Mat Pos
+indeces (Mat m) = Mat [[(x,y) | y <- [0..length (m !! x)-1]] |
+                                x <- [0..length m-1]]
+
+-- | Create a matrix of zeros
+zeros :: Int -> Int -> Mat Int
+zeros x y = Mat (replicate x $ replicate y 0)

life.hs

@@ -1,16 +1,10 @@
 {-#LANGUAGE TypeSynonymInstances, FlexibleInstances#-}
 import Data.Maybe (listToMaybe)
 import Data.List  (intercalate)
+import Matrix
 
-data Mat a = Mat [[a]]
-type Pos  = (Int, Int)
-
-type Grid = Mat Cell
 type Cell = Int
-
-
-instance Functor Mat where
-  fmap f (Mat m) = Mat ((map . map) f m)
+type Grid = Mat Cell
 
 instance Show Grid where
   show (Mat m) = concatMap ((++"\n") . intercalate " " . map replace) m
@@ -18,20 +12,6 @@ instance Show Grid where
       replace 1 = "■"
       replace 0 = "'"
 
--- | Safely access a list
--- [4,1,5,9] ?? 2 == Just 5
--- [5,7] ?? 3 == Nothing
-(??) :: [a] -> Int -> Maybe a
-xs     ?? n | n < 0 =  Nothing
-[]     ?? _         =  Nothing
-(x:_)  ?? 0         =  Just x
-(_:xs) ?? n         =  xs ?? (n-1)
-
--- | Create a Mat of Indeces for a grid
-indeces :: Grid -> Mat Pos
-indeces (Mat m) = Mat [[(x,y) | y <- [0..length (m !! x)-1]] |
-                                x <- [0..length m-1]]
-
 -- | Get the state of a cell
 -- 0 when out of the grid
 (!) :: Grid -> Pos -> Cell
@@ -39,11 +19,7 @@ indeces (Mat m) = Mat [[(x,y) | y <- [0..length (m !! x)-1]] |
   Nothing -> 0
   Just v  -> v
 
--- | Create empty grid
-void :: Int -> Int -> Grid
-void x y = Mat (replicate x $ replicate y 0)
-
--- | Give the list of neighbours cells
+-- | List of neighbours cells
 near :: Grid -> Pos -> [Cell]
 near g (x, y) = [g ! (x+x', y+y') | x' <- [-1..1],
                                     y' <- [-1..1],