gen/src/Gen/Types/Map.hs · gogol

on 2835fc2 help sign in

49 lines 1.6 kB history raw

1{-# LANGUAGE FlexibleInstances #-}

4 -- Module : Gen.Types.Map

6-- License : This Source Code Form is subject to the terms of

7-- the Mozilla Public License, v. 2.0.

8-- A copy of the MPL can be found in the LICENSE file or

9-- you can obtain it at http://mozilla.org/MPL/2.0/.

10-- Maintainer : Brendan Hay <brendan.g.hay@gmail.com>

11-- Stability : provisional

12-- Portability : non-portable (GHC extensions)

14module Gen.Types.Map where

16import Control.Lens

17import Control.Monad

18import Data.Aeson

19import Data.Aeson.Types

20import Data.Bifunctor

21import Data.Hashable

22import qualified Data.HashMap.Strict as Map

23import Data.Maybe

24import Data.Text (Text)

26type Map = Map.HashMap

28vMapMaybe :: (Eq k, Hashable k)

29 => (a -> Maybe b)

30 -> Map k a

31 -> Map k b

32vMapMaybe f = runIdentity . kvTraverseMaybe (const (pure . f))

34kvTraverseMaybe :: (Applicative f, Eq k, Hashable k)

35 => (k -> a -> f (Maybe b))

36 -> Map k a

37 -> f (Map k b)

38kvTraverseMaybe f = fmap (Map.map fromJust . Map.filter isJust)

39 . Map.traverseWithKey f

41class (Hashable a, Eq a) => TextKey a where

42 toKey :: Text -> a

44instance (TextKey k, FromJSON v) => FromJSON (Map k v) where

45 parseJSON = fmap (Map.fromList . map (first toKey) . Map.toList)

46 . parseJSON

48-- instance (TextKey k, ToJSON v) => ToJSON (Map k v) where

49-- toJSON = toJSON . map (first fromKey) . Map.toList