Implement custom at and ix for NewInt types

2025-08-25 00:50:41 +01:00
parent d776c91cfd
commit 25e64d5378
2 changed files with 17 additions and 13 deletions
@@ -4,6 +4,8 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE TypeFamilies #-}
+--{-# LANGUAGE StandaloneDeriving #-}
 module NewInt where

 --import qualified Data.IntSet as IS
@@ -19,11 +21,14 @@ newtype NewIntMap a b = NIntMap { _unNIntMap :: IM.IntMap b}
    deriving newtype (Monoid,Semigroup)
    deriving (Eq,Ord,Show,Read)

--instance Ixed (NewIntMap (NewInt a)) where
--    type Index (NewIntMap (NewInt a)) = NewInt a
--    type Index (NewIntMap (NewInt a)) = NewInt a
--    ix :: (NewInt a) -> IndexedTraversal' (NewIntMap (NewInt a))
--    ix (NInt k) (NewIntMap m) = NIntMap <$> ix k m
+type instance Index (NewIntMap a b) = NewInt a
+type instance IxValue (NewIntMap a b) = b
+
+instance Ixed (NewIntMap a b) where
+    ix (NInt i) f (NIntMap m) = fmap NIntMap (ix i f m)
+
+instance At (NewIntMap a b) where
+    at (NInt i) f (NIntMap m) = fmap NIntMap (at i f m)

 makeLenses ''NewInt
 makeLenses ''NewIntMap