Allow for no-ammo muzzles

src/Dodge/Event/Input.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE LambdaCase #-}
 {- | Capture input events, store them in structures for later use.
 -}
 module Dodge.Event.Input (
@@ -28,17 +29,20 @@ handleKeyboardEvent kev = case keyboardEventKeyMotion kev of
     scode = (keysymScancode . keyboardEventKeysym) kev
 
 addTermSignal :: Scancode -> Input -> Input
-addTermSignal sc = case sc of
-    ScancodeBackspace -> textInput .:~ Left TSbackspace
-    ScancodeEscape -> textInput .:~ Left TSescape
-    ScancodeReturn -> textInput .:~ Left TSreturn
-    ScancodeDelete -> textInput .:~ Left TSdelete
-    ScancodeTab -> textInput .:~ Left TStab
-    ScancodeLeft -> textInput .:~ Left TSleft
-    ScancodeRight -> textInput .:~ Left TSright
-    ScancodeUp -> textInput .:~ Left TSup
-    ScancodeDown -> textInput .:~ Left TSdown
-    _ -> id
+addTermSignal = maybe id (\ts -> textInput .:~ Left ts) . scToTS
+
+scToTS :: Scancode -> Maybe TermSignal
+scToTS = \case
+    ScancodeBackspace -> Just TSbackspace
+    ScancodeEscape -> Just TSescape
+    ScancodeReturn -> Just TSreturn
+    ScancodeDelete -> Just TSdelete
+    ScancodeTab -> Just TStab
+    ScancodeLeft -> Just TSleft
+    ScancodeRight -> Just TSright
+    ScancodeUp -> Just TSup
+    ScancodeDown -> Just TSdown
+    _ -> Nothing
 
 handleMouseMotionEvent :: MouseMotionEventData -> Configuration -> Input -> Input
 handleMouseMotionEvent mmev cfig = set mousePos themousepos . set mouseMoving True