Display multiple messages per turn

When tracking message history, save messages associated with the turn
they were displayed on, which allows us to have the notion of the
"current turn's" messages (provided via a MonoComonad instance).

1 files changed, 17 insertions, 4 deletions

diff --git a/src/Xanthous/Orphans.hs b/src/Xanthous/Orphans.hs
index 22325f6366..610067a375 100644
--- a/src/Xanthous/Orphans.hs
+++ b/src/Xanthous/Orphans.hs
@@ -25,7 +25,8 @@ import           Text.Mustache.Type ( showKey )
 
 instance forall s a.
   ( Cons s s a a
-  , MonoFoldable s
+  , IsSequence s
+  , Element s ~ a
   ) => Cons (NonNull s) (NonNull s) a a where
   _Cons = prism hither yon
     where
@@ -35,9 +36,21 @@ instance forall s a.
         in impureNonNull $ a <| s
 
       yon :: NonNull s -> Either (NonNull s) (a, NonNull s)
-      yon ns = case ns ^? _Cons of
-        Nothing -> Left ns
-        Just (a, ns') -> Right (a, ns')
+      yon ns = case nuncons ns of
+        (_, Nothing) -> Left ns
+        (x, Just xs) -> Right (x, xs)
+
+instance forall a. Cons (NonEmpty a) (NonEmpty a) a a where
+  _Cons = prism hither yon
+    where
+      hither :: (a, NonEmpty a) -> NonEmpty a
+      hither (a, x :| xs) = a :| (x : xs)
+
+      yon :: NonEmpty a -> Either (NonEmpty a) (a, NonEmpty a)
+      yon ns@(x :| xs) = case xs of
+        (y : ys) -> Right (x, y :| ys)
+        [] -> Left ns
+
 
 instance Arbitrary PName where
   arbitrary = PName . pack <$> listOf1 (elements ['a'..'z'])