Add bang patterns for the cube_at function (Ben Lippmeier).

diff --git a/src/Grid.hs b/src/Grid.hs
index ca66437a6bb13b73d591b68d1b16d3ead8d60c89..71e39a055110aab2a8be5378f374d8051bc1be93 100644 (file)
--- a/src/Grid.hs
+++ b/src/Grid.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE BangPatterns #-}
 -- | The Grid module just contains the Grid type and two constructors
 --   for it. We hide the main Grid constructor because we don't want
 --   to allow instantiation of a grid with h <= 0.
@@ -65,7 +66,7 @@ make_grid grid_size values
 --   centered on that position. If there is no cube there (i.e. the
 --   position is outside of the grid), it will throw an error.
 cube_at :: Grid -> Int -> Int -> Int -> Cube
-cube_at g i j k
+cube_at !g !i !j !k
     | i < 0      = error "i < 0 in cube_at"
     | i >= xsize = error "i >= xsize in cube_at"
     | j < 0      = error "j < 0 in cube_at"