Introduce idea of world event flags

src/Dodge/Data/World.hs

@@ -13,6 +13,7 @@ module Dodge.Data.World (
     module Dodge.Data.Input,
 ) where
 
+import Data.Set (Set)
 import Dodge.Data.SaveSlot
 import Control.Lens
 import qualified Data.Map.Strict as M
@@ -24,6 +25,10 @@ import Dodge.Data.SoundOrigin
 import Sound.Data
 import System.Random
 
+data WorldEventFlag = InventoryChange
+    | CombineInventoryChange
+    deriving (Eq,Ord,Enum,Bounded)
+
 data World = World
     { _cWorld :: CWorld
     , _randGen :: StdGen
@@ -33,6 +38,7 @@ data World = World
     , _testFloat :: Float
     , _rbOptions :: RightButtonOptions
     , _hud :: HUD
+    , _worldEventFlags :: Set WorldEventFlag
     }
 
 --    deriving (Eq, Ord, Show, Read) --Generic, Flat)