Improve configuration handling

src/Dodge/Update.hs

@@ -23,14 +23,15 @@ import qualified Data.IntMap.Strict as IM
 import qualified Data.Map as M
 import Control.Lens
 {- | The update step.
-If the '_menuState' is not 'InGame', this is the identity.
-This means that the only way to change the world is using event handling.
+If '_menuLayers' is not empty, or the saving screen, this is the identity.
+In such menus, the only way to change the world is using event handling.
  -}
 update :: World -> World
-update w 
-    | _menuState w /= InGame = w
-    | otherwise = 
-            let w1 = updateParticles' . updateProjectiles 
+update w = case _menuLayers w of
+    (ConfigSaveScreen x: ls) -> w & menuLayers .~ (ConfigSaveScreen (x-1) : ls)
+    (ConfigSaveScreen 0: ls) -> w & menuLayers .~ ls
+    (_ : _) -> w    
+    []  ->  let w1 = updateParticles' . updateProjectiles 
                                       . updateLightSources
                                       . zoneClouds
                                       . updateClouds
@@ -101,7 +102,7 @@ setTestStringIO = fmap (\ w -> set testString (show $ s w) w)
     where s w = (-.-) <$> (w ^? creatures . ix 0 . crPos) <*> (w ^? creatures . ix 0 . crOldPos)
 
 checkEndGame :: World -> World
-checkEndGame w | _crHP (you w) < 1 = haltSound $ w {_menuState = GameOverMenu}
+checkEndGame w | _crHP (you w) < 1 = haltSound $ w {_menuLayers = [GameOverMenu]}
                | otherwise         = w
 
 updateClouds :: World -> World