gen/src/Gen/Types/Map.hs · gogol

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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 Data.Aeson

18import Data.Bifunctor

19import Data.Hashable

20import qualified Data.HashMap.Strict as Map

21import Data.Maybe

22import Data.Text (Text)

24type Map = Map.HashMap

26vMapMaybe :: (Eq k, Hashable k)

27 => (a -> Maybe b)

28 -> Map k a

29 -> Map k b

30vMapMaybe f = runIdentity . kvTraverseMaybe (const (pure . f))

32kvTraverseMaybe :: (Applicative f, Eq k, Hashable k)

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

34 -> Map k a

35 -> f (Map k b)

36kvTraverseMaybe f = fmap (Map.map fromJust . Map.filter isJust)

37 . Map.traverseWithKey f

39class (Hashable a, Eq a) => TextKey a where

40 toKey :: Text -> a

42instance (TextKey k, FromJSON v) => FromJSON (Map k v) where

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

44 . parseJSON