hix-0.7.2: lib/Hix/Data/Json.hs

module Hix.Data.Json where

import Data.Aeson (FromJSON (parseJSON), Key, Object, (.:?))
import Data.Aeson.Types (Parser)
import Distribution.Parsec (Parsec, eitherParsec)

aesonParsec ::
  Parsec a =>
  String ->
  Parser a
aesonParsec =
  leftA fail . eitherParsec

newtype JsonParsec a =
  JsonParsec a
  deriving stock (Eq, Show, Generic)

instance Parsec a => FromJSON (JsonParsec a) where
  parseJSON v = do
    raw <- parseJSON v
    JsonParsec <$> aesonParsec raw

jsonParsec :: JsonParsec a -> a
jsonParsec = coerce

foldMissing ::
  Monoid a =>
  FromJSON a =>
  Object ->
  Key ->
  Parser a
foldMissing o k =
  fold <$> o .:? k

newtype JsonEither a b =
  JsonEither (Either a b)
  deriving stock (Eq, Show)

jsonEither :: JsonEither a b -> Either a b
jsonEither = coerce

instance (FromJSON a, FromJSON b) => FromJSON (JsonEither a b) where
  parseJSON v =
    JsonEither <$> ((Right <$> parseJSON v) <|> (Left <$> parseJSON v))