IsMap.hs

-- |
-- Module      : Streamly.Internal.Data.IsMap
-- Copyright   : (c) 2022 Composewell Technologies
-- License     : BSD-3-Clause
-- Maintainer  : streamly@composewell.com
-- Stability   : experimental
-- Portability : GHC

module Streamly.Internal.Data.IsMap (IsMap(..)) where

import Data.Kind (Type)
import Data.Map.Strict (Map)

import qualified Data.IntMap.Strict as IntMap
import qualified Data.Map.Strict as Map

-- XXX Try unpacked-containers

class IsMap f where
    type Key f :: Type

    mapEmpty :: f a
    mapAlterF :: Functor g =>
        (Maybe a -> g (Maybe a)) -> Key f -> f a -> g (f a)
    -- These can be implemented in terms of alterF itself
    mapLookup :: Key f -> f a -> Maybe a
    mapInsert :: Key f -> a -> f a -> f a
    mapDelete :: Key f -> f a -> f a
    mapUnion :: f a -> f a -> f a
    mapNull :: f a -> Bool

instance Ord k => IsMap (Map k) where
    type Key (Map k) = k

    mapEmpty = Map.empty
    mapAlterF = Map.alterF
    mapLookup = Map.lookup
    mapInsert = Map.insert
    mapDelete = Map.delete
    mapUnion = Map.union
    mapNull = Map.null

instance IsMap IntMap.IntMap where
    type Key IntMap.IntMap = Int

    mapEmpty = IntMap.empty
    mapAlterF = IntMap.alterF
    mapLookup = IntMap.lookup
    mapInsert = IntMap.insert
    mapDelete = IntMap.delete
    mapUnion = IntMap.union
    mapNull = IntMap.null