{-# LANGUAGE DataKinds #-}
{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TypeFamilies #-}
module Octane.Type.Dictionary
( Dictionary(..)
) where
import Data.Function ((&))
import qualified Control.DeepSeq as DeepSeq
import qualified Data.Aeson as Aeson
import qualified Data.Binary as Binary
import qualified Data.Default.Class as Default
import qualified Data.Map.Strict as Map
import qualified Data.OverloadedRecords.TH as OverloadedRecords
import qualified GHC.Exts as Exts
import qualified GHC.Generics as Generics
import qualified Octane.Type.Text as Text
newtype Dictionary a = Dictionary
{ dictionaryUnpack :: (Map.Map Text.Text a)
} deriving (Eq, Generics.Generic)
$(OverloadedRecords.overloadedRecord Default.def ''Dictionary)
-- | Elements are stored with the key first, then the value. The dictionary
-- ends when a key is @"None"@.
instance (Binary.Binary a) =>
Binary.Binary (Dictionary a) where
get = do
element <- getElement
if Map.null element
then element & Dictionary & pure
else do
Dictionary elements <- Binary.get
elements & Map.union element & Dictionary & pure
put dictionary = do
dictionary & #unpack & Map.assocs & mapM_ putElement
noneKey & Binary.put
-- | Allows creating 'Dictionary' values with 'Exts.fromList'. Also allows
-- 'Dictionary' literals with the @OverloadedLists@ extension.
instance Exts.IsList (Dictionary a) where
type Item (Dictionary a) = (Text.Text, a)
fromList items = Dictionary (Map.fromList items)
toList dictionary = Map.toList (#unpack dictionary)
instance (DeepSeq.NFData a) =>
DeepSeq.NFData (Dictionary a)
-- | Shown as @fromList [("key","value")]@.
instance (Show a) =>
Show (Dictionary a) where
show dictionary = show (#unpack dictionary)
-- | Encoded directly as a JSON object.
instance (Aeson.ToJSON a) =>
Aeson.ToJSON (Dictionary a) where
toJSON dictionary = dictionary & #unpack & Map.mapKeys #unpack & Aeson.toJSON
getElement
:: (Binary.Binary a)
=> Binary.Get (Map.Map Text.Text a)
getElement = do
key <- Binary.get
if key == noneKey
then pure Map.empty
else do
value <- Binary.get
value & Map.singleton key & pure
putElement
:: (Binary.Binary a)
=> (Text.Text, a) -> Binary.Put
putElement (key, value) = do
Binary.put key
Binary.put value
noneKey :: Text.Text
noneKey = "None"