fix(xanthous): Only use alphabetic chars for menu items r/2682

Previously, we were using `smallestNotIn` for selecting new characters
for menu items with duplicate chatacters - this uses the 'Bounded'
instance for the type, which for Char meant the first character we would
always select was \NUL - making it look like the menu item had no
character, and making it impossible to actually select the menu item.
This introduces an AlphaChar newtype, which is a wrapper around Char
whose Bounded and Enum instances only use alphabetic characters (a-ZA-Z)
and uses that for menu characters instead.

Change-Id: If34ed9e9ce84f2bcb1cb87432cc6273f40b69f72
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3229
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

1 files changed, 3 insertions, 2 deletions

diff --git a/users/grfn/xanthous/src/Xanthous/Game/Prompt.hs b/users/grfn/xanthous/src/Xanthous/Game/Prompt.hs
index 30b5fe7545e0..fa4c3903deb1 100644
--- a/users/grfn/xanthous/src/Xanthous/Game/Prompt.hs
+++ b/users/grfn/xanthous/src/Xanthous/Game/Prompt.hs
@@ -28,7 +28,8 @@ import           Brick.Widgets.Edit (Editor, editorText, getEditContents)
 import           Test.QuickCheck
 import           Test.QuickCheck.Arbitrary.Generic
 --------------------------------------------------------------------------------
-import           Xanthous.Util (smallestNotIn)
+--------------------------------------------------------------------------------
+import           Xanthous.Util (smallestNotIn, AlphaChar (..))
 import           Xanthous.Data (Direction, Position)
 import           Xanthous.Data.App (ResourceName)
 import qualified Xanthous.Data.App as Resource
@@ -175,7 +176,7 @@ mkMenuItems :: (MonoFoldable f, Element f ~ (Char, MenuOption a))
             -> Map Char (MenuOption a)
 mkMenuItems = flip foldl' mempty $ \items (chr, option) ->
   let chr' = if has (ix chr) items
-             then smallestNotIn $ keys items
+             then getAlphaChar . smallestNotIn . map AlphaChar $ keys items
              else chr
   in items & at chr' ?~ option