Refactor text input

src/Dodge/Update/Input.hs

@@ -1,5 +1,6 @@
 module Dodge.Update.Input 
     ( updateKeyInGame
+    , doInputScreenInput
     ) where
 
 import Dodge.WorldPos
@@ -14,6 +15,24 @@ import Dodge.Menu
 import Dodge.Data.Universe
 import SDL
 import LensHelp
+import qualified Data.Text as T
+
+doInputScreenInput :: Universe -> Universe
+doInputScreenInput u = u & uvScreenLayers . _head . scInput %~ (`T.append` thetext)
+    & checkBackspace
+  where
+    thetext = u ^. uvWorld . input . textInput
+    checkBackspace = case u ^. uvWorld . input . pressedKeys . at ScancodeBackspace of
+        Just InitialPress -> f
+        Just LongPress -> f
+        _ -> id
+    f = uvScreenLayers . _head . scInput %~ doBackspace
+
+doBackspace :: T.Text -> T.Text
+doBackspace t = case T.unsnoc t of
+    Nothing -> t
+    Just (t', _) -> t'
+
 
 updateKeyInGame :: Universe -> Scancode -> PressType -> Universe
 updateKeyInGame  uv sc InitialPress = case sc of