From 7b97c9c65dbbfe7d5105070aed38622985ab0f96 Mon Sep 17 00:00:00 2001
From: Rnhmjoj <micheleguerinirocco@me.com>
Date: Sun, 8 Mar 2015 01:34:41 +0100
Subject: [PATCH] Use applicative style

---
 Matrix.hs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Matrix.hs b/Matrix.hs
index dc66cd4..b4e7b88 100644
--- a/Matrix.hs
+++ b/Matrix.hs
@@ -1,4 +1,6 @@
 module Matrix where
+
+import Control.Applicative
 import Data.List  (intercalate)
 
 newtype Mat a = Mat [[a]]
@@ -26,8 +28,9 @@ group n xs = take n xs : group n (drop n xs)
 
 -- | 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]]
+indeces (Mat m) = Mat (group y pos) where
+	(x, y) = (length m, length (m !! 0))
+	pos = liftA2 (,) [0..x-1] [0..y-1]
 
 -- | Create a constant matrix
 constant :: a -> Int -> Int -> Mat a