@@ -5,20 +5,16 @@
5{-# LANGUAGE FlexibleInstances #-}
5{-# LANGUAGE FlexibleInstances #-}
6{-# LANGUAGE GADTs #-}
6{-# LANGUAGE GADTs #-}
7{-# LANGUAGE MultiParamTypeClasses #-}
7{-# LANGUAGE MultiParamTypeClasses #-}
8−{-# LANGUAGE NamedFieldPuns #-}
9{-# LANGUAGE NoImplicitPrelude #-}
8{-# LANGUAGE NoImplicitPrelude #-}
10{-# LANGUAGE OverloadedStrings #-}
9{-# LANGUAGE OverloadedStrings #-}
10+{-# LANGUAGE PolyKinds #-}
11{-# LANGUAGE RecordWildCards #-}
11{-# LANGUAGE RecordWildCards #-}
12{-# LANGUAGE ScopedTypeVariables #-}
12{-# LANGUAGE ScopedTypeVariables #-}
13{-# LANGUAGE TypeOperators #-}
13{-# LANGUAGE TypeOperators #-}
14−{-# LANGUAGE TypeSynonymInstances #-}
14+{-# LANGUAGE TupleSections #-}
15{-# LANGUAGE UndecidableInstances #-}
15{-# LANGUAGE UndecidableInstances #-}
16{-# LANGUAGE ViewPatterns #-}
16{-# LANGUAGE ViewPatterns #-}
18−#if __GLASGOW_HASKELL__ >= 706
19−{-# LANGUAGE PolyKinds #-}
22#include "incoherent-compat.h"
18#include "incoherent-compat.h"
23#include "overlapping-compat.h"
19#include "overlapping-compat.h"
@@ -46,6 +42,9 @@ module Data.Aeson.Types.FromJSON
46 , coerceFromJSONKeyFunction
42 , coerceFromJSONKeyFunction
47 , mapFromJSONKeyFunction
43 , mapFromJSONKeyFunction
49 -- * List functions
48 -- * List functions
50 , listParser
49 , listParser
@@ -61,12 +60,14 @@ module Data.Aeson.Types.FromJSON
61 , fromJSON
60 , fromJSON
62 , ifromJSON
61 , ifromJSON
63 , typeMismatch
62 , typeMismatch
64 , parseField
64 , parseField
65 , parseFieldMaybe
65 , parseFieldMaybe
66 , parseFieldMaybe'
66 , parseFieldMaybe'
67 , explicitParseField
67 , explicitParseField
68 , explicitParseFieldMaybe
68 , explicitParseFieldMaybe
69 , explicitParseFieldMaybe'
69 , explicitParseFieldMaybe'
70 -- ** Operators
71 -- ** Operators
@@ -79,14 +80,14 @@ module Data.Aeson.Types.FromJSON
80import Prelude.Compat
81import Prelude.Compat
82−import Control.Applicative ((<|>), Const(..))
83+import Control.Applicative ((<|>), Const(..), liftA2)
83−import Control.Monad ((<=<), zipWithM)
84+import Control.Monad (zipWithM)
84import Data.Aeson.Internal.Functions (mapKey)
85import Data.Aeson.Internal.Functions (mapKey)
85import Data.Aeson.Parser.Internal (eitherDecodeWith, jsonEOF)
86import Data.Aeson.Parser.Internal (eitherDecodeWith, jsonEOF)
86import Data.Aeson.Types.Generic
87import Data.Aeson.Types.Generic
87import Data.Aeson.Types.Internal
88import Data.Aeson.Types.Internal
88import Data.Bits (unsafeShiftR)
89import Data.Bits (unsafeShiftR)
89−import Data.Fixed (Fixed, HasResolution)
90+import Data.Fixed (Fixed, HasResolution (resolution), Nano)
90import Data.Functor.Compose (Compose(..))
91import Data.Functor.Compose (Compose(..))
91import Data.Functor.Identity (Identity(..))
92import Data.Functor.Identity (Identity(..))
92import Data.Functor.Product (Product(..))
93import Data.Functor.Product (Product(..))
@@ -102,8 +103,10 @@ import Data.Scientific (Scientific, base10Exponent)
102import Data.Tagged (Tagged(..))
103import Data.Tagged (Tagged(..))
103import Data.Text (Text, pack, unpack)
104import Data.Text (Text, pack, unpack)
104import Data.Time (Day, DiffTime, LocalTime, NominalDiffTime, TimeOfDay, UTCTime, ZonedTime)
105import Data.Time (Day, DiffTime, LocalTime, NominalDiffTime, TimeOfDay, UTCTime, ZonedTime)
105−import Data.Time.Format (parseTime)
106+import Data.Time.Calendar.Compat (CalendarDiffDays (..), DayOfWeek (..))
107+import Data.Time.LocalTime.Compat (CalendarDiffTime (..))
108+import Data.Time.Clock.System.Compat (SystemTime (..))
106−import Data.Time.Locale.Compat (defaultTimeLocale)
109+import Data.Time.Format.Compat (parseTimeM, defaultTimeLocale)
107import Data.Traversable as Tr (sequence)
110import Data.Traversable as Tr (sequence)
108import Data.Vector (Vector)
111import Data.Vector (Vector)
109import Data.Version (Version, parseVersion)
112import Data.Version (Version, parseVersion)
@@ -115,9 +118,9 @@ import GHC.Generics
115import Numeric.Natural (Natural)
118import Numeric.Natural (Natural)
116import Text.ParserCombinators.ReadP (readP_to_S)
119import Text.ParserCombinators.ReadP (readP_to_S)
117import Unsafe.Coerce (unsafeCoerce)
120import Unsafe.Coerce (unsafeCoerce)
118−import qualified Data.Aeson.Compat as Compat
119import qualified Data.Aeson.Parser.Time as Time
121import qualified Data.Aeson.Parser.Time as Time
120import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly, scientific)
122import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly, scientific)
123+import qualified Data.ByteString.Lazy as L
121import qualified Data.DList as DList
124import qualified Data.DList as DList
122import qualified Data.HashMap.Strict as H
125import qualified Data.HashMap.Strict as H
123import qualified Data.HashSet as HashSet
126import qualified Data.HashSet as HashSet
@@ -140,18 +143,20 @@ import qualified Data.Vector.Primitive as VP
140import qualified Data.Vector.Storable as VS
143import qualified Data.Vector.Storable as VS
141import qualified Data.Vector.Unboxed as VU
144import qualified Data.Vector.Unboxed as VU
143−#ifndef HAS_COERCIBLE
146+import qualified GHC.Exts as Exts
144−#define HAS_COERCIBLE (__GLASGOW_HASKELL__ >= 707)
147+import qualified Data.Primitive.Array as PM
148+import qualified Data.Primitive.SmallArray as PM
149+import qualified Data.Primitive.Types as PM
151+#if MIN_VERSION_primitive(0,6,4)
152+#if !MIN_VERSION_primitive(0,7,0)
153+import qualified Data.Primitive.UnliftedArray as PM
155+import qualified Data.Primitive.PrimArray as PM
148import Data.Coerce (Coercible, coerce)
159import Data.Coerce (Coercible, coerce)
149−coerce' :: Coercible a b => a -> b
153−coerce' = unsafeCoerce
156parseIndexedJSON :: (Value -> Parser a) -> Int -> Value -> Parser a
161parseIndexedJSON :: (Value -> Parser a) -> Int -> Value -> Parser a
157parseIndexedJSON p idx value = p value <?> Index idx
162parseIndexedJSON p idx value = p value <?> Index idx
@@ -160,7 +165,7 @@ parseIndexedJSON p idx value = p value <?> Index idx
160parseIndexedJSONPair :: (Value -> Parser a) -> (Value -> Parser b) -> Int -> Value -> Parser (a, b)
165parseIndexedJSONPair :: (Value -> Parser a) -> (Value -> Parser b) -> Int -> Value -> Parser (a, b)
161parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
166parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
163− p = withArray "(k,v)" $ \ab ->
168+ p = withArray "(k, v)" $ \ab ->
164 let n = V.length ab
169 let n = V.length ab
165 in if n == 2
170 in if n == 2
166 then (,) <$> parseJSONElemAtIndex keyParser 0 ab
171 then (,) <$> parseJSONElemAtIndex keyParser 0 ab
@@ -173,33 +178,33 @@ parseJSONElemAtIndex :: (Value -> Parser a) -> Int -> V.Vector Value -> Parser a
173parseJSONElemAtIndex p idx ary = p (V.unsafeIndex ary idx) <?> Index idx
178parseJSONElemAtIndex p idx ary = p (V.unsafeIndex ary idx) <?> Index idx
175parseRealFloat :: RealFloat a => String -> Value -> Parser a
180parseRealFloat :: RealFloat a => String -> Value -> Parser a
176−parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
181+parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
177−parseRealFloat _ Null = pure (0/0)
182+parseRealFloat _ Null = pure (0/0)
178−parseRealFloat expected v = typeMismatch expected v
183+parseRealFloat name v = prependContext name (unexpected v)
179{-# INLINE parseRealFloat #-}
184{-# INLINE parseRealFloat #-}
181−parseIntegralFromScientific :: forall a. Integral a => String -> Scientific -> Parser a
186+parseIntegralFromScientific :: forall a. Integral a => Scientific -> Parser a
182−parseIntegralFromScientific expected s =
187+parseIntegralFromScientific s =
183 case Scientific.floatingOrInteger s :: Either Double a of
188 case Scientific.floatingOrInteger s :: Either Double a of
184 Right x -> pure x
189 Right x -> pure x
185− Left _ -> fail $ "expected " ++ expected ++ ", encountered floating number " ++ show s
190+ Left _ -> fail $ "unexpected floating number " ++ show s
186{-# INLINE parseIntegralFromScientific #-}
191{-# INLINE parseIntegralFromScientific #-}
188parseIntegral :: Integral a => String -> Value -> Parser a
193parseIntegral :: Integral a => String -> Value -> Parser a
189−parseIntegral expected =
194+parseIntegral name =
190− withBoundedScientific expected $ parseIntegralFromScientific expected
195+ prependContext name . withBoundedScientific' parseIntegralFromScientific
191{-# INLINE parseIntegral #-}
196{-# INLINE parseIntegral #-}
193−parseBoundedIntegralFromScientific :: (Bounded a, Integral a) => String -> Scientific -> Parser a
198+parseBoundedIntegralFromScientific :: (Bounded a, Integral a) => Scientific -> Parser a
194−parseBoundedIntegralFromScientific expected s = maybe
199+parseBoundedIntegralFromScientific s = maybe
195− (fail $ expected ++ " is either floating or will cause over or underflow: " ++ show s)
200+ (fail $ "value is either floating or will cause over or underflow " ++ show s)
197 (Scientific.toBoundedInteger s)
202 (Scientific.toBoundedInteger s)
198{-# INLINE parseBoundedIntegralFromScientific #-}
203{-# INLINE parseBoundedIntegralFromScientific #-}
200parseBoundedIntegral :: (Bounded a, Integral a) => String -> Value -> Parser a
205parseBoundedIntegral :: (Bounded a, Integral a) => String -> Value -> Parser a
201−parseBoundedIntegral expected =
206+parseBoundedIntegral name =
202− withScientific expected $ parseBoundedIntegralFromScientific expected
207+ prependContext name . withScientific' parseBoundedIntegralFromScientific
203{-# INLINE parseBoundedIntegral #-}
208{-# INLINE parseBoundedIntegral #-}
205parseScientificText :: Text -> Parser Scientific
210parseScientificText :: Text -> Parser Scientific
@@ -209,18 +214,20 @@ parseScientificText
209 . T.encodeUtf8
214 . T.encodeUtf8
211parseIntegralText :: Integral a => String -> Text -> Parser a
216parseIntegralText :: Integral a => String -> Text -> Parser a
212−parseIntegralText expected t
217+parseIntegralText name t =
218+ prependContext name $
213− = parseScientificText t
219+ parseScientificText t
214− >>= rejectLargeExponent
220+ >>= rejectLargeExponent
215− >>= parseIntegralFromScientific expected
221+ >>= parseIntegralFromScientific
217 rejectLargeExponent :: Scientific -> Parser Scientific
223 rejectLargeExponent :: Scientific -> Parser Scientific
218− rejectLargeExponent s = withBoundedScientific expected pure (Number s)
224+ rejectLargeExponent s = withBoundedScientific' pure (Number s)
219{-# INLINE parseIntegralText #-}
225{-# INLINE parseIntegralText #-}
221parseBoundedIntegralText :: (Bounded a, Integral a) => String -> Text -> Parser a
227parseBoundedIntegralText :: (Bounded a, Integral a) => String -> Text -> Parser a
222−parseBoundedIntegralText expected t =
228+parseBoundedIntegralText name t =
229+ prependContext name $
223− parseScientificText t >>= parseBoundedIntegralFromScientific expected
230+ parseScientificText t >>= parseBoundedIntegralFromScientific
225parseOptionalFieldWith :: (Value -> Parser (Maybe a))
232parseOptionalFieldWith :: (Value -> Parser (Maybe a))
226 -> Object -> Text -> Parser (Maybe a)
233 -> Object -> Text -> Parser (Maybe a)
@@ -280,14 +287,21 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
281-- The basic ways to signal a failed conversion are as follows:
288-- The basic ways to signal a failed conversion are as follows:
283−-- * 'empty' and 'mzero' work, but are terse and uninformative;
290+-- * 'fail' yields a custom error message: it is the recommended way of
291+-- reporting a failure;
285−-- * 'fail' yields a custom error message;
293+-- * 'Control.Applicative.empty' (or 'Control.Monad.mzero') is uninformative:
294+-- use it when the error is meant to be caught by some @('<|>')@;
287−-- * 'typeMismatch' produces an informative message for cases when the
296+-- * 'typeMismatch' can be used to report a failure when the encountered value
288−-- value encountered is not of the expected type.
297+-- is not of the expected JSON type; 'unexpected' is an appropriate alternative
298+-- when more than one type may be expected, or to keep the expected type
301+-- 'prependFailure' (or 'modifyFailure') add more information to a parser's
290−-- An example type and instance using 'typeMismatch':
304+-- An example type and instance using 'typeMismatch' and 'prependFailure':
293-- \-- Allow ourselves to write 'Text' literals.
307-- \-- Allow ourselves to write 'Text' literals.
@@ -301,13 +315,15 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
301-- '<*>' v '.:' \"y\"
315-- '<*>' v '.:' \"y\"
303-- \-- We do not expect a non-'Object' value here.
317-- \-- We do not expect a non-'Object' value here.
304−-- \-- We could use 'mzero' to fail, but 'typeMismatch'
318+-- \-- We could use 'Control.Applicative.empty' to fail, but 'typeMismatch'
305-- \-- gives a much more informative error message.
319-- \-- gives a much more informative error message.
320+-- 'parseJSON' invalid =
321+-- 'prependFailure' "parsing Coord failed, "
306−-- 'parseJSON' invalid = 'typeMismatch' \"Coord\" invalid
322+-- ('typeMismatch' \"Object\" invalid)
309-- For this common case of only being concerned with a single
325-- For this common case of only being concerned with a single
310−-- type of JSON value, the functions 'withObject', 'withNumber', etc.
326+-- type of JSON value, the functions 'withObject', 'withScientific', etc.
311-- are provided. Their use is to be preferred when possible, since
327-- are provided. Their use is to be preferred when possible, since
312-- they are more terse. Using 'withObject', we can rewrite the above instance
328-- they are more terse. Using 'withObject', we can rewrite the above instance
313-- (assuming the same language extension and data type) as:
329-- (assuming the same language extension and data type) as:
@@ -346,7 +362,7 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
348-- The default implementation will be equivalent to
364-- The default implementation will be equivalent to
349−-- @parseJSON = 'genericParseJSON' 'defaultOptions'@; If you need different
365+-- @parseJSON = 'genericParseJSON' 'defaultOptions'@; if you need different
350-- options, you can customize the generic decoding by defining:
366-- options, you can customize the generic decoding by defining:
@@ -364,13 +380,11 @@ class FromJSON a where
364 parseJSON = genericParseJSON defaultOptions
380 parseJSON = genericParseJSON defaultOptions
366 parseJSONList :: Value -> Parser [a]
382 parseJSONList :: Value -> Parser [a]
367− parseJSONList (Array a)
383+ parseJSONList = withArray "[]" $ \a ->
368− = zipWithM (parseIndexedJSON parseJSON) [0..]
384+ zipWithM (parseIndexedJSON parseJSON) [0..]
369 . V.toList
385 . V.toList
372− parseJSONList v = typeMismatch "[a]" v
374-------------------------------------------------------------------------------
388-------------------------------------------------------------------------------
375-- Classes and types for map keys
389-- Classes and types for map keys
376-------------------------------------------------------------------------------
390-------------------------------------------------------------------------------
@@ -382,6 +396,16 @@ class FromJSON a where
382-- > newtype SomeId = SomeId { getSomeId :: Text }
396-- > newtype SomeId = SomeId { getSomeId :: Text }
383-- > deriving (Eq,Ord,Hashable,FromJSONKey)
397-- > deriving (Eq,Ord,Hashable,FromJSONKey)
399+-- If you have a sum of nullary constructors, you may use the generic
403+-- data Color = Red | Green | Blue
406+-- instance 'FromJSONKey' Color where
407+-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
385class FromJSONKey a where
409class FromJSONKey a where
386 -- | Strategy for parsing the key of a map-like container.
410 -- | Strategy for parsing the key of a map-like container.
387 fromJSONKey :: FromJSONKeyFunction a
411 fromJSONKey :: FromJSONKeyFunction a
@@ -404,11 +428,7 @@ class FromJSONKey a where
404-- At the moment this type is intentionally not exported. 'FromJSONKeyFunction'
428-- At the moment this type is intentionally not exported. 'FromJSONKeyFunction'
405-- can be inspected, but cannot be constructed.
429-- can be inspected, but cannot be constructed.
406data CoerceText a where
430data CoerceText a where
408 CoerceText :: Coercible Text a => CoerceText a
431 CoerceText :: Coercible Text a => CoerceText a
410− CoerceText :: CoerceText a
413-- | This type is related to 'ToJSONKeyFunction'. If 'FromJSONKeyValue' is used in the
433-- | This type is related to 'ToJSONKeyFunction'. If 'FromJSONKeyValue' is used in the
414-- 'FromJSONKey' instance, then 'ToJSONKeyValue' should be used in the 'ToJSONKey'
434-- 'FromJSONKey' instance, then 'ToJSONKeyValue' should be used in the 'ToJSONKey'
@@ -428,7 +448,7 @@ data FromJSONKeyFunction a
429-- | Only law abiding up to interpretation
449-- | Only law abiding up to interpretation
430instance Functor FromJSONKeyFunction where
450instance Functor FromJSONKeyFunction where
431− fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce')
451+ fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce)
432 fmap h (FromJSONKeyText f) = FromJSONKeyText (h . f)
452 fmap h (FromJSONKeyText f) = FromJSONKeyText (h . f)
433 fmap h (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap h . f)
453 fmap h (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap h . f)
434 fmap h (FromJSONKeyValue f) = FromJSONKeyValue (fmap h . f)
454 fmap h (FromJSONKeyValue f) = FromJSONKeyValue (fmap h . f)
@@ -442,9 +462,7 @@ instance Functor FromJSONKeyFunction where
443-- On pre GHC 7.8 this is unconstrainted function.
463-- On pre GHC 7.8 this is unconstrainted function.
444fromJSONKeyCoerce ::
464fromJSONKeyCoerce ::
446 Coercible Text a =>
465 Coercible Text a =>
448 FromJSONKeyFunction a
466 FromJSONKeyFunction a
449fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
467fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
@@ -452,60 +470,91 @@ fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
453-- See note on 'fromJSONKeyCoerce'.
471-- See note on 'fromJSONKeyCoerce'.
454coerceFromJSONKeyFunction ::
472coerceFromJSONKeyFunction ::
456 Coercible a b =>
473 Coercible a b =>
458 FromJSONKeyFunction a -> FromJSONKeyFunction b
474 FromJSONKeyFunction a -> FromJSONKeyFunction b
460coerceFromJSONKeyFunction = coerce
475coerceFromJSONKeyFunction = coerce
462−coerceFromJSONKeyFunction (FromJSONKeyCoerce CoerceText) = FromJSONKeyCoerce CoerceText
463−coerceFromJSONKeyFunction (FromJSONKeyText f) = FromJSONKeyText (coerce' . f)
464−coerceFromJSONKeyFunction (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap coerce' . f)
465−coerceFromJSONKeyFunction (FromJSONKeyValue f) = FromJSONKeyValue (fmap coerce' . f)
469 "FromJSONKeyCoerce: fmap id" forall (x :: FromJSONKeyFunction a).
478 "FromJSONKeyCoerce: fmap id" forall (x :: FromJSONKeyFunction a).
470 fmap id x = x
479 fmap id x = x
474 "FromJSONKeyCoerce: fmap coerce" forall x .
482 "FromJSONKeyCoerce: fmap coerce" forall x .
475 fmap coerce x = coerceFromJSONKeyFunction x
483 fmap coerce x = coerceFromJSONKeyFunction x
479-- | Same as 'fmap'. Provided for the consistency with 'ToJSONKeyFunction'.
486-- | Same as 'fmap'. Provided for the consistency with 'ToJSONKeyFunction'.
480mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b
487mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b
481mapFromJSONKeyFunction = fmap
488mapFromJSONKeyFunction = fmap
490+-- | 'fromJSONKey' for 'Generic' types.
491+-- These types must be sums of nullary constructors, whose names will be used
492+-- as keys for JSON objects.
494+-- See also 'genericToJSONKey'.
499+-- data Color = Red | Green | Blue
500+-- deriving 'Generic'
502+-- instance 'FromJSONKey' Color where
503+-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
505+genericFromJSONKey :: forall a. (Generic a, GFromJSONKey (Rep a))
507+ -> FromJSONKeyFunction a
508+genericFromJSONKey opts = FromJSONKeyTextParser $ \t ->
509+ case parseSumFromString (keyModifier opts) t of
511+ "invalid key " ++ show t ++ ", expected one of " ++ show cnames
512+ Just k -> pure (to k)
514+ cnames = unTagged2 (constructorTags (keyModifier opts) :: Tagged2 (Rep a) [String])
516+class (ConstructorNames f, SumFromString f) => GFromJSONKey f where
517+instance (ConstructorNames f, SumFromString f) => GFromJSONKey f where
483-------------------------------------------------------------------------------
519-------------------------------------------------------------------------------
484-- Functions needed for documentation
520-- Functions needed for documentation
485-------------------------------------------------------------------------------
521-------------------------------------------------------------------------------
487-- | Fail parsing due to a type mismatch, with a descriptive message.
523-- | Fail parsing due to a type mismatch, with a descriptive message.
489−-- Example usage:
525+-- The following wrappers should generally be prefered:
526+-- 'withObject', 'withArray', 'withText', 'withBool'.
491−-- @
528+-- ==== Error message example
492−-- instance FromJSON Coord where
529+--
493−-- parseJSON ('Object' v) = {- type matches, life is good -}
530+-- > typeMismatch "Object" (String "oops")
494−-- parseJSON wat = 'typeMismatch' \"Coord\" wat
531+-- > -- Error: "expected Object, but encountered String"
496−typeMismatch :: String -- ^ The name of the type you are trying to parse.
532+typeMismatch :: String -- ^ The name of the JSON type being parsed
533+ -- (@\"Object\"@, @\"Array\"@, @\"String\"@, @\"Number\"@,
534+ -- @\"Boolean\"@, or @\"Null\"@).
497 -> Value -- ^ The actual value encountered.
535 -> Value -- ^ The actual value encountered.
498 -> Parser a
536 -> Parser a
499typeMismatch expected actual =
537typeMismatch expected actual =
500− fail $ "expected " ++ expected ++ ", encountered " ++ name
538+ fail $ "expected " ++ expected ++ ", but encountered " ++ typeOf actual
540+-- | Fail parsing due to a type mismatch, when the expected types are implicit.
542+-- ==== Error message example
544+-- > unexpected (String "oops")
545+-- > -- Error: "unexpected String"
546+unexpected :: Value -> Parser a
547+unexpected actual = fail $ "unexpected " ++ typeOf actual
549+-- | JSON type of a value, name of the head constructor.
550+typeOf :: Value -> String
502− name = case actual of
551+typeOf v = case v of
503− Object _ -> "Object"
552+ Object _ -> "Object"
504− Array _ -> "Array"
553+ Array _ -> "Array"
505− String _ -> "String"
554+ String _ -> "String"
506− Number _ -> "Number"
555+ Number _ -> "Number"
507− Bool _ -> "Boolean"
556+ Bool _ -> "Boolean"
508− Null -> "Null"
557+ Null -> "Null"
510-------------------------------------------------------------------------------
559-------------------------------------------------------------------------------
511-- Lifings of FromJSON and ToJSON to unary and binary type constructors
560-- Lifings of FromJSON and ToJSON to unary and binary type constructors
@@ -586,9 +635,8 @@ class FromJSON2 f where
586 -> (Value -> Parser b)
635 -> (Value -> Parser b)
587 -> (Value -> Parser [b])
636 -> (Value -> Parser [b])
588 -> Value -> Parser [f a b]
637 -> Value -> Parser [f a b]
589− liftParseJSONList2 fa ga fb gb v = case v of
638+ liftParseJSONList2 fa ga fb gb = withArray "[]" $ \vals ->
590− Array vals -> fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
639+ fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
591− _ -> typeMismatch "[a]" v
593-- | Lift the standard 'parseJSON' function through the type constructor.
641-- | Lift the standard 'parseJSON' function through the type constructor.
594parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
642parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
@@ -602,7 +650,7 @@ parseJSON2 = liftParseJSON2 parseJSON parseJSONList parseJSON parseJSONList
602-- | Helper function to use with 'liftParseJSON'. See 'Data.Aeson.ToJSON.listEncoding'.
650-- | Helper function to use with 'liftParseJSON'. See 'Data.Aeson.ToJSON.listEncoding'.
603listParser :: (Value -> Parser a) -> Value -> Parser [a]
651listParser :: (Value -> Parser a) -> Value -> Parser [a]
604listParser f (Array xs) = fmap V.toList (V.mapM f xs)
652listParser f (Array xs) = fmap V.toList (V.mapM f xs)
605−listParser _ v = typeMismatch "[a]" v
653+listParser _ v = typeMismatch "Array" v
606{-# INLINE listParser #-}
654{-# INLINE listParser #-}
608-------------------------------------------------------------------------------
656-------------------------------------------------------------------------------
@@ -620,69 +668,137 @@ instance (FromJSON a) => FromJSON [a] where
620-- Functions
668-- Functions
621-------------------------------------------------------------------------------
669-------------------------------------------------------------------------------
671+-- | Add context to a failure message, indicating the name of the structure
674+-- > prependContext "MyType" (fail "[error message]")
675+-- > -- Error: "parsing MyType failed, [error message]"
676+prependContext :: String -> Parser a -> Parser a
677+prependContext name = prependFailure ("parsing " ++ name ++ " failed, ")
623−-- | @'withObject' expected f value@ applies @f@ to the 'Object' when @value@
679+-- | @'withObject' name f value@ applies @f@ to the 'Object' when @value@
624−-- is an 'Object' and fails using @'typeMismatch' expected@ otherwise.
680+-- is an 'Data.Aeson.Object' and fails otherwise.
682+-- ==== Error message example
684+-- > withObject "MyType" f (String "oops")
685+-- > -- Error: "parsing MyType failed, expected Object, but encountered String"
625withObject :: String -> (Object -> Parser a) -> Value -> Parser a
686withObject :: String -> (Object -> Parser a) -> Value -> Parser a
626−withObject _ f (Object obj) = f obj
687+withObject _ f (Object obj) = f obj
627−withObject expected _ v = typeMismatch expected v
688+withObject name _ v = prependContext name (typeMismatch "Object" v)
628{-# INLINE withObject #-}
689{-# INLINE withObject #-}
630−-- | @'withText' expected f value@ applies @f@ to the 'Text' when @value@ is a
691+-- | @'withText' name f value@ applies @f@ to the 'Text' when @value@ is a
631−-- 'String' and fails using @'typeMismatch' expected@ otherwise.
692+-- 'Data.Aeson.String' and fails otherwise.
694+-- ==== Error message example
696+-- > withText "MyType" f Null
697+-- > -- Error: "parsing MyType failed, expected String, but encountered Null"
632withText :: String -> (Text -> Parser a) -> Value -> Parser a
698withText :: String -> (Text -> Parser a) -> Value -> Parser a
633−withText _ f (String txt) = f txt
699+withText _ f (String txt) = f txt
634−withText expected _ v = typeMismatch expected v
700+withText name _ v = prependContext name (typeMismatch "String" v)
635{-# INLINE withText #-}
701{-# INLINE withText #-}
637-- | @'withArray' expected f value@ applies @f@ to the 'Array' when @value@ is
703-- | @'withArray' expected f value@ applies @f@ to the 'Array' when @value@ is
638−-- an 'Array' and fails using @'typeMismatch' expected@ otherwise.
704+-- an 'Data.Aeson.Array' and fails otherwise.
706+-- ==== Error message example
708+-- > withArray "MyType" f (String "oops")
709+-- > -- Error: "parsing MyType failed, expected Array, but encountered String"
639withArray :: String -> (Array -> Parser a) -> Value -> Parser a
710withArray :: String -> (Array -> Parser a) -> Value -> Parser a
640−withArray _ f (Array arr) = f arr
711+withArray _ f (Array arr) = f arr
641−withArray expected _ v = typeMismatch expected v
712+withArray name _ v = prependContext name (typeMismatch "Array" v)
642{-# INLINE withArray #-}
713{-# INLINE withArray #-}
644−-- | @'withScientific' expected f value@ applies @f@ to the 'Scientific' number
715+-- | @'withScientific' name f value@ applies @f@ to the 'Scientific' number
645−-- when @value@ is a 'Number' and fails using @'typeMismatch' expected@
716+-- when @value@ is a 'Data.Aeson.Number' and fails using 'typeMismatch'
646-- otherwise.
717-- otherwise.
648-- /Warning/: If you are converting from a scientific to an unbounded
719-- /Warning/: If you are converting from a scientific to an unbounded
649-- type such as 'Integer' you may want to add a restriction on the
720-- type such as 'Integer' you may want to add a restriction on the
650-- size of the exponent (see 'withBoundedScientific') to prevent
721-- size of the exponent (see 'withBoundedScientific') to prevent
651-- malicious input from filling up the memory of the target system.
722-- malicious input from filling up the memory of the target system.
724+-- ==== Error message example
726+-- > withScientific "MyType" f (String "oops")
727+-- > -- Error: "parsing MyType failed, expected Number, but encountered String"
652withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
728withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
653−withScientific _ f (Number scientific) = f scientific
729+withScientific _ f (Number scientific) = f scientific
654−withScientific expected _ v = typeMismatch expected v
730+withScientific name _ v = prependContext name (typeMismatch "Number" v)
655{-# INLINE withScientific #-}
731{-# INLINE withScientific #-}
657−-- | @'withBoundedScientific' expected f value@ applies @f@ to the 'Scientific' number
733+-- | A variant of 'withScientific' which doesn't use 'prependContext', so that
658−-- when @value@ is a 'Number' and fails using @'typeMismatch' expected@
734+-- such context can be added separately in a way that also applies when the
659−-- otherwise.
735+-- continuation @f :: Scientific -> Parser a@ fails.
661−-- The conversion will also fail wyth a @'typeMismatch' if the
737+-- /Warning/: If you are converting from a scientific to an unbounded
662−-- 'Scientific' exponent is larger than 1024.
738+-- type such as 'Integer' you may want to add a restriction on the
739+-- size of the exponent (see 'withBoundedScientific') to prevent
740+-- malicious input from filling up the memory of the target system.
742+-- ==== Error message examples
744+-- > withScientific' f (String "oops")
745+-- > -- Error: "unexpected String"
747+-- > prependContext "MyType" (withScientific' f (String "oops"))
748+-- > -- Error: "parsing MyType failed, unexpected String"
749+withScientific' :: (Scientific -> Parser a) -> Value -> Parser a
750+withScientific' f v = case v of
752+ _ -> typeMismatch "Number" v
753+{-# INLINE withScientific' #-}
755+-- | @'withBoundedScientific' name f value@ applies @f@ to the 'Scientific' number
756+-- when @value@ is a 'Number' with exponent less than or equal to 1024.
663withBoundedScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
757withBoundedScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
664−withBoundedScientific _ f v@(Number scientific) =
758+withBoundedScientific name f v = withBoundedScientific_ (prependContext name) f v
665− if base10Exponent scientific > 1024
666− then typeMismatch "a number with exponent <= 1024" v
668−withBoundedScientific expected _ v = typeMismatch expected v
669{-# INLINE withBoundedScientific #-}
759{-# INLINE withBoundedScientific #-}
761+-- | A variant of 'withBoundedScientific' which doesn't use 'prependContext',
762+-- so that such context can be added separately in a way that also applies
763+-- when the continuation @f :: Scientific -> Parser a@ fails.
764+withBoundedScientific' :: (Scientific -> Parser a) -> Value -> Parser a
765+withBoundedScientific' f v = withBoundedScientific_ id f v
766+{-# INLINE withBoundedScientific' #-}
768+-- | A variant of 'withBoundedScientific_' parameterized by a function to apply
769+-- to the 'Parser' in case of failure.
770+withBoundedScientific_ :: (Parser a -> Parser a) -> (Scientific -> Parser a) -> Value -> Parser a
771+withBoundedScientific_ whenFail f (Number scientific) =
773+ then whenFail (fail msg)
776+ exp10 = base10Exponent scientific
777+ msg = "found a number with exponent " ++ show exp10 ++ ", but it must not be greater than 1024"
778+withBoundedScientific_ whenFail _ v =
779+ whenFail (typeMismatch "Number" v)
780+{-# INLINE withBoundedScientific_ #-}
671-- | @'withBool' expected f value@ applies @f@ to the 'Bool' when @value@ is a
782-- | @'withBool' expected f value@ applies @f@ to the 'Bool' when @value@ is a
672−-- 'Bool' and fails using @'typeMismatch' expected@ otherwise.
783+-- 'Boolean' and fails otherwise.
785+-- ==== Error message example
787+-- > withBool "MyType" f (String "oops")
788+-- > -- Error: "parsing MyType failed, expected Boolean, but encountered String"
673withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
789withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
674−withBool _ f (Bool arr) = f arr
790+withBool _ f (Bool arr) = f arr
675−withBool expected _ v = typeMismatch expected v
791+withBool name _ v = prependContext name (typeMismatch "Boolean" v)
676{-# INLINE withBool #-}
792{-# INLINE withBool #-}
678-- | Decode a nested JSON-encoded string.
794-- | Decode a nested JSON-encoded string.
679withEmbeddedJSON :: String -> (Value -> Parser a) -> Value -> Parser a
795withEmbeddedJSON :: String -> (Value -> Parser a) -> Value -> Parser a
680withEmbeddedJSON _ innerParser (String txt) =
796withEmbeddedJSON _ innerParser (String txt) =
681− either fail innerParser $ eitherDecode (Compat.fromStrict $ T.encodeUtf8 txt)
797+ either fail innerParser $ eitherDecode (L.fromStrict $ T.encodeUtf8 txt)
683 eitherDecode = eitherFormatError . eitherDecodeWith jsonEOF ifromJSON
799 eitherDecode = eitherFormatError . eitherDecodeWith jsonEOF ifromJSON
684 eitherFormatError = either (Left . uncurry formatError) Right
800 eitherFormatError = either (Left . uncurry formatError) Right
685−withEmbeddedJSON name _ v = typeMismatch name v
801+withEmbeddedJSON name _ v = prependContext name (typeMismatch "String" v)
686{-# INLINE withEmbeddedJSON #-}
802{-# INLINE withEmbeddedJSON #-}
688-- | Convert a value from JSON, failing if the types do not match.
804-- | Convert a value from JSON, failing if the types do not match.
@@ -747,7 +863,7 @@ parseFieldMaybe' = (.:!)
747-- E.g. @'explicitParseField' 'parseJSON1' :: ('FromJSON1' f, 'FromJSON' a) -> 'Object' -> 'Text' -> 'Parser' (f a)@
863-- E.g. @'explicitParseField' 'parseJSON1' :: ('FromJSON1' f, 'FromJSON' a) -> 'Object' -> 'Text' -> 'Parser' (f a)@
748explicitParseField :: (Value -> Parser a) -> Object -> Text -> Parser a
864explicitParseField :: (Value -> Parser a) -> Object -> Text -> Parser a
749explicitParseField p obj key = case H.lookup key obj of
865explicitParseField p obj key = case H.lookup key obj of
750− Nothing -> fail $ "key " ++ show key ++ " not present"
866+ Nothing -> fail $ "key " ++ show key ++ " not found"
751 Just v -> p v <?> Key key
867 Just v -> p v <?> Key key
752{-# INLINE explicitParseField #-}
868{-# INLINE explicitParseField #-}
@@ -797,6 +913,37 @@ instance OVERLAPPABLE_ (GFromJSON arity a) => GFromJSON arity (M1 i c a) where
797 -- parsed value:
913 -- parsed value:
798 gParseJSON opts fargs = fmap M1 . gParseJSON opts fargs
914 gParseJSON opts fargs = fmap M1 . gParseJSON opts fargs
916+-- Information for error messages
918+type TypeName = String
919+type ConName = String
921+-- | Add the name of the type being parsed to a parser's error messages.
922+contextType :: TypeName -> Parser a -> Parser a
923+contextType = prependContext
925+-- | Add the tagKey that will be looked up while building an ADT
926+-- | Produce the error equivalent to
927+-- | Left "Error in $: parsing T failed, expected an object with keys "tag" and
928+-- | "contents", where "tag" i-- |s associated to one of ["Foo", "Bar"],
929+-- | The parser returned error was: could not find key "tag"
930+contextTag :: Text -> [String] -> Parser a -> Parser a
931+contextTag tagKey cnames = prependFailure
932+ ("expected Object with key \"" ++ unpack tagKey ++ "\"" ++
933+ " containing one of " ++ show cnames ++ ", ")
935+-- | Add the name of the constructor being parsed to a parser's error messages.
936+contextCons :: ConName -> TypeName -> Parser a -> Parser a
937+contextCons cname tname = prependContext (showCons cname tname)
939+-- | Render a constructor as @\"MyType(MyConstructor)\"@.
940+showCons :: ConName -> TypeName -> String
941+showCons cname tname = tname ++ "(" ++ cname ++ ")"
943+--------------------------------------------------------------------------------
945+-- Parsing single fields
800instance (FromJSON a) => GFromJSON arity (K1 i a) where
947instance (FromJSON a) => GFromJSON arity (K1 i a) where
801 -- Constant values are decoded using their FromJSON instance:
948 -- Constant values are decoded using their FromJSON instance:
802 gParseJSON _opts _ = fmap K1 . parseJSON
949 gParseJSON _opts _ = fmap K1 . parseJSON
@@ -811,342 +958,499 @@ instance (FromJSON1 f) => GFromJSON One (Rec1 f) where
811 -- FromJSON1 instance:
958 -- FromJSON1 instance:
812 gParseJSON _opts (From1Args pj pjl) = fmap Rec1 . liftParseJSON pj pjl
959 gParseJSON _opts (From1Args pj pjl) = fmap Rec1 . liftParseJSON pj pjl
814−instance GFromJSON arity U1 where
961+instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
815− -- Empty constructors are expected to be encoded as an empty array:
962+ -- If an occurrence of the last type parameter is nested inside two
963+ -- composed types, it is decoded by using the outermost type's FromJSON1
964+ -- instance to generically decode the innermost type:
816− gParseJSON _opts _ v
965+ gParseJSON opts fargs =
817− | isEmptyArray v = pure U1
966+ let gpj = gParseJSON opts fargs in
818− | otherwise = typeMismatch "unit constructor (U1)" v
967+ fmap Comp1 . liftParseJSON gpj (listParser gpj)
969+--------------------------------------------------------------------------------
971+instance (GFromJSON' arity a, Datatype d) => GFromJSON arity (D1 d a) where
972+ -- Meta-information, which is not handled elsewhere, is just added to the
974+ gParseJSON opts fargs = fmap M1 . gParseJSON' (tname :* opts :* fargs)
976+ tname = moduleName proxy ++ "." ++ datatypeName proxy
977+ proxy = undefined :: M1 _i d _f _p
979+-- | 'GFromJSON', after unwrapping the 'D1' constructor, now carrying the data
981+class GFromJSON' arity f where
982+ gParseJSON' :: TypeName :* Options :* FromArgs arity a
986+-- | Single constructor.
820instance ( ConsFromJSON arity a
987instance ( ConsFromJSON arity a
821 , AllNullary (C1 c a) allNullary
988 , AllNullary (C1 c a) allNullary
822 , ParseSum arity (C1 c a) allNullary
989 , ParseSum arity (C1 c a) allNullary
823− ) => GFromJSON arity (D1 d (C1 c a)) where
991+ ) => GFromJSON' arity (C1 c a) where
824 -- The option 'tagSingleConstructors' determines whether to wrap
992 -- The option 'tagSingleConstructors' determines whether to wrap
825 -- a single-constructor type.
993 -- a single-constructor type.
826− gParseJSON opts fargs
994+ gParseJSON' p@(_ :* opts :* _)
827 | tagSingleConstructors opts
995 | tagSingleConstructors opts
829− . (unTagged :: Tagged allNullary (Parser (C1 c a p)) -> Parser (C1 c a p))
996+ = (unTagged :: Tagged allNullary (Parser (C1 c a p)) -> Parser (C1 c a p))
830− . parseSum opts fargs
997+ . parseSum p
831− | otherwise = fmap M1 . fmap M1 . consParseJSON opts fargs
998+ | otherwise = fmap M1 . consParseJSON (cname :* p)
833−instance (ConsFromJSON arity a) => GFromJSON arity (C1 c a) where
1000+ cname = conName (undefined :: M1 _i c _f _p)
834− -- Constructors need to be decoded differently depending on whether they're
1001+
835− -- a record or not. This distinction is made by consParseJSON:
1002+-- | Multiple constructors.
836− gParseJSON opts fargs = fmap M1 . consParseJSON opts fargs
838−instance ( FromProduct arity a, FromProduct arity b
839− , ProductSize a, ProductSize b
840− ) => GFromJSON arity (a :*: b) where
841− -- Products are expected to be encoded to an array. Here we check whether we
842− -- got an array of the same size as the product, then parse each of the
843− -- product's elements using parseProduct:
844− gParseJSON opts fargs = withArray "product (:*:)" $ \arr ->
845− let lenArray = V.length arr
846− lenProduct = (unTagged2 :: Tagged2 (a :*: b) Int -> Int)
848− if lenArray == lenProduct
849− then parseProduct opts fargs arr 0 lenProduct
850− else fail $ "When expecting a product of " ++ show lenProduct ++
851− " values, encountered an Array of " ++ show lenArray ++
854−instance ( AllNullary (a :+: b) allNullary
1003+instance ( AllNullary (a :+: b) allNullary
855− , ParseSum arity (a :+: b) allNullary
1004+ , ParseSum arity (a :+: b) allNullary
856− ) => GFromJSON arity (a :+: b) where
1005+ ) => GFromJSON' arity (a :+: b) where
857 -- If all constructors of a sum datatype are nullary and the
1006 -- If all constructors of a sum datatype are nullary and the
858 -- 'allNullaryToStringTag' option is set they are expected to be
1007 -- 'allNullaryToStringTag' option is set they are expected to be
859 -- encoded as strings. This distinction is made by 'parseSum':
1008 -- encoded as strings. This distinction is made by 'parseSum':
860− gParseJSON opts fargs =
1009+ gParseJSON' p =
861− (unTagged :: Tagged allNullary (Parser ((a :+: b) d)) ->
1010+ (unTagged :: Tagged allNullary (Parser ((a :+: b) _d)) ->
862− Parser ((a :+: b) d))
1011+ Parser ((a :+: b) _d))
863− . parseSum opts fargs
1012+ . parseSum p
865−instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
866− -- If an occurrence of the last type parameter is nested inside two
867− -- composed types, it is decoded by using the outermost type's FromJSON1
868− -- instance to generically decode the innermost type:
869− gParseJSON opts fargs =
870− let gpj = gParseJSON opts fargs in
871− fmap Comp1 . liftParseJSON gpj (listParser gpj)
873--------------------------------------------------------------------------------
1014--------------------------------------------------------------------------------
875class ParseSum arity f allNullary where
1016class ParseSum arity f allNullary where
876− parseSum :: Options -> FromArgs arity a
1017+ parseSum :: TypeName :* Options :* FromArgs arity a
877− -> Value -> Tagged allNullary (Parser (f a))
1019+ -> Tagged allNullary (Parser (f a))
1021+instance ( ConstructorNames f
879−instance ( SumFromString f
1022+ , SumFromString f
880 , FromPair arity f
1023 , FromPair arity f
881 , FromTaggedObject arity f
1024 , FromTaggedObject arity f
882 , FromUntaggedValue arity f
1025 , FromUntaggedValue arity f
883 ) => ParseSum arity f True where
1026 ) => ParseSum arity f True where
884− parseSum opts fargs
1027+ parseSum p@(tname :* opts :* _)
885− | allNullaryToStringTag opts = Tagged . parseAllNullarySum opts
1028+ | allNullaryToStringTag opts = Tagged . parseAllNullarySum tname opts
886− | otherwise = Tagged . parseNonAllNullarySum opts fargs
1029+ | otherwise = Tagged . parseNonAllNullarySum p
1031+instance ( ConstructorNames f
888−instance ( FromPair arity f
1032+ , FromPair arity f
889 , FromTaggedObject arity f
1033 , FromTaggedObject arity f
890 , FromUntaggedValue arity f
1034 , FromUntaggedValue arity f
891 ) => ParseSum arity f False where
1035 ) => ParseSum arity f False where
892− parseSum opts fargs = Tagged . parseNonAllNullarySum opts fargs
1036+ parseSum p = Tagged . parseNonAllNullarySum p
894--------------------------------------------------------------------------------
1038--------------------------------------------------------------------------------
896−parseAllNullarySum :: SumFromString f => Options -> Value -> Parser (f a)
1040+parseAllNullarySum :: (SumFromString f, ConstructorNames f)
1041+ => TypeName -> Options -> Value -> Parser (f a)
897−parseAllNullarySum opts = withText "Text" $ \key ->
1042+parseAllNullarySum tname opts =
1043+ withText tname $ \tag ->
898− maybe (notFound key) return $
1044+ maybe (badTag tag) return $
899− parseSumFromString opts key
1045+ parseSumFromString modifier tag
1047+ badTag tag = failWithCTags tname modifier $ \cnames ->
1048+ "expected one of the tags " ++ show cnames ++
1049+ ", but found tag " ++ show tag
1050+ modifier = constructorTagModifier opts
1052+-- | Fail with an informative error message about a mismatched tag.
1053+-- The error message is parameterized by the list of expected tags,
1054+-- to be inferred from the result type of the parser.
1056+ :: forall f a t. ConstructorNames f
1057+ => TypeName -> (String -> t) -> ([t] -> String) -> Parser (f a)
1058+failWithCTags tname modifier f =
1059+ contextType tname . fail $ f cnames
1061+ cnames = unTagged2 (constructorTags modifier :: Tagged2 f [t])
901class SumFromString f where
1063class SumFromString f where
902− parseSumFromString :: Options -> Text -> Maybe (f a)
1064+ parseSumFromString :: (String -> String) -> Text -> Maybe (f a)
904instance (SumFromString a, SumFromString b) => SumFromString (a :+: b) where
1066instance (SumFromString a, SumFromString b) => SumFromString (a :+: b) where
905 parseSumFromString opts key = (L1 <$> parseSumFromString opts key) <|>
1067 parseSumFromString opts key = (L1 <$> parseSumFromString opts key) <|>
906 (R1 <$> parseSumFromString opts key)
1068 (R1 <$> parseSumFromString opts key)
908instance (Constructor c) => SumFromString (C1 c U1) where
1070instance (Constructor c) => SumFromString (C1 c U1) where
909− parseSumFromString opts key | key == name = Just $ M1 U1
1071+ parseSumFromString modifier key
1072+ | key == name = Just $ M1 U1
910− | otherwise = Nothing
1073+ | otherwise = Nothing
912− name = pack $ constructorTagModifier opts $
913− conName (undefined :: t c U1 p)
1075+ name = pack $ modifier $ conName (undefined :: M1 _i c _f _p)
915−--------------------------------------------------------------------------------
1077+-- For genericFromJSONKey
1078+instance SumFromString a => SumFromString (D1 d a) where
1079+ parseSumFromString modifier key = M1 <$> parseSumFromString modifier key
1081+-- | List of all constructor tags.
1082+constructorTags :: ConstructorNames a => (String -> t) -> Tagged2 a [t]
1083+constructorTags modifier =
1084+ fmap DList.toList (constructorNames' modifier)
1086+-- | List of all constructor names of an ADT, after a given conversion
1087+-- function. (Better inlining.)
1088+class ConstructorNames a where
1089+ constructorNames' :: (String -> t) -> Tagged2 a (DList.DList t)
1091+instance (ConstructorNames a, ConstructorNames b) => ConstructorNames (a :+: b) where
1092+ constructorNames' = liftA2 append constructorNames' constructorNames'
1095+ :: Tagged2 a (DList.DList t)
1096+ -> Tagged2 b (DList.DList t)
1097+ -> Tagged2 (a :+: b) (DList.DList t)
1098+ append (Tagged2 xs) (Tagged2 ys) = Tagged2 (DList.append xs ys)
1100+instance Constructor c => ConstructorNames (C1 c a) where
1101+ constructorNames' f = Tagged2 (pure (f cname))
1103+ cname = conName (undefined :: M1 _i c _f _p)
1105+-- For genericFromJSONKey
1106+instance ConstructorNames a => ConstructorNames (D1 d a) where
1107+ constructorNames' = retag . constructorNames'
1109+ retag :: Tagged2 a u -> Tagged2 (D1 d a) u
1110+ retag (Tagged2 x) = Tagged2 x
1112+--------------------------------------------------------------------------------
917−parseNonAllNullarySum :: ( FromPair arity f
1113+parseNonAllNullarySum :: forall f c arity.
918 , FromTaggedObject arity f
1115 , FromTaggedObject arity f
919 , FromUntaggedValue arity f
1116 , FromUntaggedValue arity f
1117+ , ConstructorNames f
920− ) => Options -> FromArgs arity c
1118+ ) => TypeName :* Options :* FromArgs arity c
921 -> Value -> Parser (f c)
1119 -> Value -> Parser (f c)
922−parseNonAllNullarySum opts fargs =
1120+parseNonAllNullarySum p@(tname :* opts :* _) =
923 case sumEncoding opts of
1121 case sumEncoding opts of
924 TaggedObject{..} ->
1122 TaggedObject{..} ->
925− withObject "Object" $ \obj -> do
1123+ withObject tname $ \obj -> do
926− tag <- obj .: pack tagFieldName
1124+ tag <- contextType tname . contextTag tagKey cnames_ $ obj .: tagKey
927− fromMaybe (notFound tag) $
1125+ fromMaybe (badTag tag <?> Key tagKey) $
928− parseFromTaggedObject opts fargs contentsFieldName obj tag
1126+ parseFromTaggedObject (tag :* contentsFieldName :* p) obj
1128+ tagKey = pack tagFieldName
1129+ badTag tag = failWith_ $ \cnames ->
1130+ "expected tag field to be one of " ++ show cnames ++
1131+ ", but found tag " ++ show tag
1132+ cnames_ = unTagged2 (constructorTags (constructorTagModifier opts) :: Tagged2 f [String])
930 ObjectWithSingleField ->
1134 ObjectWithSingleField ->
931− withObject "Object" $ \obj ->
932− case H.toList obj of
1135+ withObject tname $ \obj -> case H.toList obj of
933− [pair@(tag, _)] -> fromMaybe (notFound tag) $
1136+ [(tag, v)] -> maybe (badTag tag) (<?> Key tag) $
934− parsePair opts fargs pair
1137+ parsePair (tag :* p) v
935− _ -> fail "Object doesn't have a single field"
1138+ _ -> contextType tname . fail $
1139+ "expected an Object with a single pair, but found " ++
1140+ show (H.size obj) ++ " pairs"
1142+ badTag tag = failWith_ $ \cnames ->
1143+ "expected an Object with a single pair where the tag is one of " ++
1144+ show cnames ++ ", but found tag " ++ show tag
937 TwoElemArray ->
1146 TwoElemArray ->
938− withArray "Array" $ \arr ->
1147+ withArray tname $ \arr -> case V.length arr of
939− if V.length arr == 2
1148+ 2 | String tag <- V.unsafeIndex arr 0 ->
940− then case V.unsafeIndex arr 0 of
1149+ maybe (badTag tag <?> Index 0) (<?> Index 1) $
941− String tag -> fromMaybe (notFound tag) $
942− parsePair opts fargs (tag, V.unsafeIndex arr 1)
1150+ parsePair (tag :* p) (V.unsafeIndex arr 1)
1152+ contextType tname $
943− _ -> fail "First element is not a String"
1153+ fail "tag element is not a String" <?> Index 0
944− else fail "Array doesn't have 2 elements"
1154+ len -> contextType tname . fail $
1155+ "expected a 2-element Array, but encountered an Array of length " ++
1158+ badTag tag = failWith_ $ \cnames ->
1159+ "expected tag of the 2-element Array to be one of " ++
1160+ show cnames ++ ", but found tag " ++ show tag
946− UntaggedValue -> parseUntaggedValue opts fargs
1162+ UntaggedValue -> parseUntaggedValue p
1164+ failWith_ = failWithCTags tname (constructorTagModifier opts)
948--------------------------------------------------------------------------------
1166--------------------------------------------------------------------------------
950class FromTaggedObject arity f where
1168class FromTaggedObject arity f where
1169+ -- The first two components of the parameter tuple are: the constructor tag
1170+ -- to match against, and the contents field name.
951− parseFromTaggedObject :: Options -> FromArgs arity a
1171+ parseFromTaggedObject
1172+ :: Text :* String :* TypeName :* Options :* FromArgs arity a
952− -> String -> Object
1173+ -> Object
953− -> Text -> Maybe (Parser (f a))
1174+ -> Maybe (Parser (f a))
955instance ( FromTaggedObject arity a, FromTaggedObject arity b) =>
1176instance ( FromTaggedObject arity a, FromTaggedObject arity b) =>
956 FromTaggedObject arity (a :+: b) where
1177 FromTaggedObject arity (a :+: b) where
957− parseFromTaggedObject opts fargs contentsFieldName obj tag =
1178+ parseFromTaggedObject p obj =
958− (fmap L1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag) <|>
1179+ (fmap L1 <$> parseFromTaggedObject p obj) <|>
959− (fmap R1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag)
1180+ (fmap R1 <$> parseFromTaggedObject p obj)
1182+instance ( IsRecord f isRecord
961−instance ( FromTaggedObject' arity f
1183+ , FromTaggedObject' arity f isRecord
962 , Constructor c
1184 , Constructor c
963 ) => FromTaggedObject arity (C1 c f) where
1185 ) => FromTaggedObject arity (C1 c f) where
964− parseFromTaggedObject opts fargs contentsFieldName obj tag
1186+ parseFromTaggedObject (tag :* contentsFieldName :* p@(_ :* opts :* _))
1189+ (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
965− | tag == name = Just $ M1 <$> parseFromTaggedObject'
1190+ parseFromTaggedObject' (contentsFieldName :* cname :* p)
966− opts fargs contentsFieldName obj
967− | otherwise = Nothing
1191+ | otherwise = const Nothing
969− name = pack $ constructorTagModifier opts $
1193+ tag' = pack $ constructorTagModifier opts cname
970− conName (undefined :: t c f p)
1194+ cname = conName (undefined :: M1 _i c _f _p)
972--------------------------------------------------------------------------------
1196--------------------------------------------------------------------------------
974−class FromTaggedObject' arity f where
1198+class FromTaggedObject' arity f isRecord where
975− parseFromTaggedObject' :: Options -> FromArgs arity a -> String
1199+ -- The first component of the parameter tuple is the contents field name.
976− -> Object -> Parser (f a)
1200+ parseFromTaggedObject'
978−class FromTaggedObject'' arity f isRecord where
979− parseFromTaggedObject'' :: Options -> FromArgs arity a -> String
1201+ :: String :* ConName :* TypeName :* Options :* FromArgs arity a
980− -> Object -> Tagged isRecord (Parser (f a))
1202+ -> Object -> Tagged isRecord (Parser (f a))
982−instance ( IsRecord f isRecord
983− , FromTaggedObject'' arity f isRecord
984− ) => FromTaggedObject' arity f where
1204+instance (RecordFromJSON arity f, FieldNames f) => FromTaggedObject' arity f True where
985− parseFromTaggedObject' opts fargs contentsFieldName =
1205+ -- Records are unpacked in the tagged object
986− (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
987− parseFromTaggedObject'' opts fargs contentsFieldName
1206+ parseFromTaggedObject' (_ :* p) = Tagged . recordParseJSON (True :* p)
989−instance (FromRecord arity f) => FromTaggedObject'' arity f True where
990− parseFromTaggedObject'' opts fargs _ =
991− Tagged . parseRecord opts fargs
993−instance (GFromJSON arity f) => FromTaggedObject'' arity f False where
1208+instance (ConsFromJSON arity f) => FromTaggedObject' arity f False where
1209+ -- Nonnullary nonrecords are encoded in the contents field
994− parseFromTaggedObject'' opts fargs contentsFieldName = Tagged .
1210+ parseFromTaggedObject' p obj = Tagged $ do
1211+ contents <- contextCons cname tname (obj .: key)
1212+ consParseJSON p' contents <?> Key key
995− (gParseJSON opts fargs <=< (.: pack contentsFieldName))
1214+ key = pack contentsFieldName
1215+ contentsFieldName :* p'@(cname :* tname :* _) = p
997−instance OVERLAPPING_ FromTaggedObject'' arity U1 False where
1217+instance OVERLAPPING_ FromTaggedObject' arity U1 False where
1218+ -- Nullary constructors don't need a contents field
998− parseFromTaggedObject'' _ _ _ _ = Tagged (pure U1)
1219+ parseFromTaggedObject' _ _ = Tagged (pure U1)
1000--------------------------------------------------------------------------------
1221--------------------------------------------------------------------------------
1223+-- | Constructors need to be decoded differently depending on whether they're
1224+-- a record or not. This distinction is made by 'ConsParseJSON'.
1002class ConsFromJSON arity f where
1225class ConsFromJSON arity f where
1003− consParseJSON :: Options -> FromArgs arity a
1227+ :: ConName :* TypeName :* Options :* FromArgs arity a
1004− -> Value -> Parser (f a)
1228+ -> Value -> Parser (f a)
1006class ConsFromJSON' arity f isRecord where
1230class ConsFromJSON' arity f isRecord where
1007− consParseJSON' :: Options -> FromArgs arity a
1232+ :: ConName :* TypeName :* Options :* FromArgs arity a
1008− -> Value -> Tagged isRecord (Parser (f a))
1233+ -> Value -> Tagged isRecord (Parser (f a))
1010instance ( IsRecord f isRecord
1235instance ( IsRecord f isRecord
1011 , ConsFromJSON' arity f isRecord
1236 , ConsFromJSON' arity f isRecord
1012 ) => ConsFromJSON arity f where
1237 ) => ConsFromJSON arity f where
1013− consParseJSON opts fargs =
1238+ consParseJSON p =
1014 (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
1239 (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
1015− . consParseJSON' opts fargs
1240+ . consParseJSON' p
1017instance OVERLAPPING_
1242instance OVERLAPPING_
1018− ( GFromJSON arity a, FromRecord arity (S1 s a)
1243+ ( GFromJSON arity a, RecordFromJSON arity (S1 s a)
1019 ) => ConsFromJSON' arity (S1 s a) True where
1244 ) => ConsFromJSON' arity (S1 s a) True where
1020− consParseJSON' opts fargs
1245+ consParseJSON' p@(cname :* tname :* opts :* fargs)
1021− | unwrapUnaryRecords opts = Tagged . gParseJSON opts fargs
1246+ | unwrapUnaryRecords opts = Tagged . fmap M1 . gParseJSON opts fargs
1022− | otherwise = Tagged . withObject "unary record" (parseRecord opts fargs)
1247+ | otherwise = Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
1024−instance FromRecord arity f => ConsFromJSON' arity f True where
1249+instance RecordFromJSON arity f => ConsFromJSON' arity f True where
1025− consParseJSON' opts fargs =
1250+ consParseJSON' p@(cname :* tname :* _) =
1026− Tagged . withObject "record (:*:)" (parseRecord opts fargs)
1251+ Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
1253+instance OVERLAPPING_
1254+ ConsFromJSON' arity U1 False where
1255+ -- Empty constructors are expected to be encoded as an empty array:
1256+ consParseJSON' (cname :* tname :* _) v =
1257+ Tagged . contextCons cname tname $ case v of
1258+ Array a | V.null a -> pure U1
1259+ | otherwise -> fail_ a
1260+ _ -> typeMismatch "Array" v
1263+ "expected an empty Array, but encountered an Array of length " ++
1266+instance OVERLAPPING_
1028−instance GFromJSON arity f => ConsFromJSON' arity f False where
1267+ GFromJSON arity f => ConsFromJSON' arity (S1 s f) False where
1268+ consParseJSON' (_ :* _ :* opts :* fargs) =
1029− consParseJSON' opts fargs = Tagged . gParseJSON opts fargs
1269+ Tagged . fmap M1 . gParseJSON opts fargs
1271+instance (ProductFromJSON arity f, ProductSize f
1272+ ) => ConsFromJSON' arity f False where
1273+ consParseJSON' p = Tagged . productParseJSON0 p
1031--------------------------------------------------------------------------------
1275--------------------------------------------------------------------------------
1033−class FromRecord arity f where
1277+class FieldNames f where
1034− parseRecord :: Options -> FromArgs arity a
1278+ fieldNames :: f a -> [Text] -> [Text]
1035− -> Object -> Parser (f a)
1037−instance ( FromRecord arity a
1280+instance (FieldNames a, FieldNames b) => FieldNames (a :*: b) where
1038− , FromRecord arity b
1281+ fieldNames _ =
1039− ) => FromRecord arity (a :*: b) where
1282+ fieldNames (undefined :: a x) .
1040− parseRecord opts fargs obj =
1283+ fieldNames (undefined :: b y)
1041− (:*:) <$> parseRecord opts fargs obj
1042− <*> parseRecord opts fargs obj
1044−instance OVERLAPPABLE_ (Selector s, GFromJSON arity a) =>
1285+instance (Selector s) => FieldNames (S1 s f) where
1045− FromRecord arity (S1 s a) where
1286+ fieldNames _ = (pack (selName (undefined :: M1 _i s _f _p)) :)
1046− parseRecord opts fargs =
1287+
1047− (<?> Key label) . gParseJSON opts fargs <=< (.: label)
1288+class RecordFromJSON arity f where
1290+ :: Bool :* ConName :* TypeName :* Options :* FromArgs arity a
1291+ -> Object -> Parser (f a)
1293+instance ( FieldNames f
1294+ , RecordFromJSON' arity f
1295+ ) => RecordFromJSON arity f where
1296+ recordParseJSON (fromTaggedSum :* p@(cname :* tname :* opts :* _)) =
1297+ \obj -> checkUnknown obj >> recordParseJSON' p obj
1299+ knownFields :: H.HashMap Text ()
1300+ knownFields = H.fromList $ map (,()) $
1301+ fieldNames (undefined :: f a)
1302+ [pack (tagFieldName (sumEncoding opts)) | fromTaggedSum]
1304+ if not (rejectUnknownFields opts)
1305+ then \_ -> return ()
1306+ else \obj -> case H.keys (H.difference obj knownFields) of
1308+ unknownFields -> contextCons cname tname $
1309+ fail ("unknown fields: " ++ show unknownFields)
1311+class RecordFromJSON' arity f where
1313+ :: ConName :* TypeName :* Options :* FromArgs arity a
1314+ -> Object -> Parser (f a)
1316+instance ( RecordFromJSON' arity a
1317+ , RecordFromJSON' arity b
1318+ ) => RecordFromJSON' arity (a :*: b) where
1319+ recordParseJSON' p obj =
1320+ (:*:) <$> recordParseJSON' p obj
1321+ <*> recordParseJSON' p obj
1323+instance OVERLAPPABLE_ (Selector s, GFromJSON arity a) =>
1324+ RecordFromJSON' arity (S1 s a) where
1325+ recordParseJSON' (cname :* tname :* opts :* fargs) obj = do
1326+ fv <- contextCons cname tname (obj .: label)
1327+ M1 <$> gParseJSON opts fargs fv <?> Key label
1049− label = pack . fieldLabelModifier opts $ selName (undefined :: t s a p)
1329+ label = pack $ fieldLabelModifier opts sname
1330+ sname = selName (undefined :: M1 _i s _f _p)
1051instance INCOHERENT_ (Selector s, FromJSON a) =>
1332instance INCOHERENT_ (Selector s, FromJSON a) =>
1052− FromRecord arity (S1 s (K1 i (Maybe a))) where
1333+ RecordFromJSON' arity (S1 s (K1 i (Maybe a))) where
1053− parseRecord opts _ obj = M1 . K1 <$> obj .:? pack label
1334+ recordParseJSON' (_ :* _ :* opts :* _) obj = M1 . K1 <$> obj .:? pack label
1055− label = fieldLabelModifier opts $
1336+ label = fieldLabelModifier opts sname
1056− selName (undefined :: t s (K1 i (Maybe a)) p)
1337+ sname = selName (undefined :: M1 _i s _f _p)
1058-- Parse an Option like a Maybe.
1339-- Parse an Option like a Maybe.
1059instance INCOHERENT_ (Selector s, FromJSON a) =>
1340instance INCOHERENT_ (Selector s, FromJSON a) =>
1060− FromRecord arity (S1 s (K1 i (Semigroup.Option a))) where
1341+ RecordFromJSON' arity (S1 s (K1 i (Semigroup.Option a))) where
1061− parseRecord opts fargs obj = wrap <$> parseRecord opts fargs obj
1342+ recordParseJSON' p obj = wrap <$> recordParseJSON' p obj
1063 wrap :: S1 s (K1 i (Maybe a)) p -> S1 s (K1 i (Semigroup.Option a)) p
1344 wrap :: S1 s (K1 i (Maybe a)) p -> S1 s (K1 i (Semigroup.Option a)) p
1064 wrap (M1 (K1 a)) = M1 (K1 (Semigroup.Option a))
1345 wrap (M1 (K1 a)) = M1 (K1 (Semigroup.Option a))
1066--------------------------------------------------------------------------------
1347--------------------------------------------------------------------------------
1350+ :: forall f arity a. (ProductFromJSON arity f, ProductSize f)
1351+ => ConName :* TypeName :* Options :* FromArgs arity a
1352+ -> Value -> Parser (f a)
1353+ -- Products are expected to be encoded to an array. Here we check whether we
1354+ -- got an array of the same size as the product, then parse each of the
1355+ -- product's elements using productParseJSON:
1356+productParseJSON0 p@(cname :* tname :* _ :* _) =
1357+ withArray (showCons cname tname) $ \arr ->
1358+ let lenArray = V.length arr
1359+ lenProduct = (unTagged2 :: Tagged2 f Int -> Int)
1361+ if lenArray == lenProduct
1362+ then productParseJSON p arr 0 lenProduct
1363+ else contextCons cname tname $
1364+ fail $ "expected an Array of length " ++ show lenProduct ++
1365+ ", but encountered an Array of length " ++ show lenArray
1068−class FromProduct arity f where
1369+class ProductFromJSON arity f where
1069− parseProduct :: Options -> FromArgs arity a
1370+ productParseJSON :: ConName :* TypeName :* Options :* FromArgs arity a
1070 -> Array -> Int -> Int
1371 -> Array -> Int -> Int
1071 -> Parser (f a)
1372 -> Parser (f a)
1073−instance ( FromProduct arity a
1374+instance ( ProductFromJSON arity a
1074− , FromProduct arity b
1375+ , ProductFromJSON arity b
1075− ) => FromProduct arity (a :*: b) where
1376+ ) => ProductFromJSON arity (a :*: b) where
1076− parseProduct opts fargs arr ix len =
1377+ productParseJSON p arr ix len =
1077− (:*:) <$> parseProduct opts fargs arr ix lenL
1378+ (:*:) <$> productParseJSON p arr ix lenL
1078− <*> parseProduct opts fargs arr ixR lenR
1379+ <*> productParseJSON p arr ixR lenR
1080 lenL = len `unsafeShiftR` 1
1381 lenL = len `unsafeShiftR` 1
1081 ixR = ix + lenL
1382 ixR = ix + lenL
1082 lenR = len - lenL
1383 lenR = len - lenL
1084−instance (GFromJSON arity a) => FromProduct arity (S1 s a) where
1385+instance (GFromJSON arity a) => ProductFromJSON arity (S1 s a) where
1085− parseProduct opts fargs arr ix _ =
1386+ productParseJSON (_ :* _ :* opts :* fargs) arr ix _ =
1086− gParseJSON opts fargs $ V.unsafeIndex arr ix
1387+ M1 <$> gParseJSON opts fargs (V.unsafeIndex arr ix) <?> Index ix
1088--------------------------------------------------------------------------------
1389--------------------------------------------------------------------------------
1090class FromPair arity f where
1391class FromPair arity f where
1392+ -- The first component of the parameter tuple is the tag to match.
1091− parsePair :: Options -> FromArgs arity a
1393+ parsePair :: Text :* TypeName :* Options :* FromArgs arity a
1092− -> Pair -> Maybe (Parser (f a))
1395+ -> Maybe (Parser (f a))
1094instance ( FromPair arity a
1397instance ( FromPair arity a
1095 , FromPair arity b
1398 , FromPair arity b
1096 ) => FromPair arity (a :+: b) where
1399 ) => FromPair arity (a :+: b) where
1097− parsePair opts fargs pair = (fmap L1 <$> parsePair opts fargs pair) <|>
1401+ (fmap L1 <$> parsePair p pair) <|>
1098− (fmap R1 <$> parsePair opts fargs pair)
1402+ (fmap R1 <$> parsePair p pair)
1100instance ( Constructor c
1404instance ( Constructor c
1101− , GFromJSON arity a
1102 , ConsFromJSON arity a
1405 , ConsFromJSON arity a
1103 ) => FromPair arity (C1 c a) where
1406 ) => FromPair arity (C1 c a) where
1104− parsePair opts fargs (tag, value)
1407+ parsePair (tag :* p@(_ :* opts :* _)) v
1105− | tag == tag' = Just $ gParseJSON opts fargs value
1408+ | tag == tag' = Just $ M1 <$> consParseJSON (cname :* p) v
1106 | otherwise = Nothing
1409 | otherwise = Nothing
1108− tag' = pack $ constructorTagModifier opts $
1411+ tag' = pack $ constructorTagModifier opts cname
1109− conName (undefined :: t c a p)
1412+ cname = conName (undefined :: M1 _i c _a _p)
1111--------------------------------------------------------------------------------
1414--------------------------------------------------------------------------------
1113class FromUntaggedValue arity f where
1416class FromUntaggedValue arity f where
1114− parseUntaggedValue :: Options -> FromArgs arity a
1417+ parseUntaggedValue :: TypeName :* Options :* FromArgs arity a
1115− -> Value -> Parser (f a)
1419+ -> Parser (f a)
1118 ( FromUntaggedValue arity a
1422 ( FromUntaggedValue arity a
1119 , FromUntaggedValue arity b
1423 , FromUntaggedValue arity b
1120 ) => FromUntaggedValue arity (a :+: b)
1424 ) => FromUntaggedValue arity (a :+: b)
1122− parseUntaggedValue opts fargs value =
1426+ parseUntaggedValue p value =
1123− L1 <$> parseUntaggedValue opts fargs value <|>
1427+ L1 <$> parseUntaggedValue p value <|>
1124− R1 <$> parseUntaggedValue opts fargs value
1428+ R1 <$> parseUntaggedValue p value
1126instance OVERLAPPABLE_
1430instance OVERLAPPABLE_
1127− ( GFromJSON arity a
1431+ ( ConsFromJSON arity a
1128− , ConsFromJSON arity a
1432+ , Constructor c
1129 ) => FromUntaggedValue arity (C1 c a)
1433 ) => FromUntaggedValue arity (C1 c a)
1131− parseUntaggedValue = gParseJSON
1435+ parseUntaggedValue p = fmap M1 . consParseJSON (cname :* p)
1437+ cname = conName (undefined :: M1 _i c _f _p)
1133instance OVERLAPPING_
1439instance OVERLAPPING_
1134 ( Constructor c )
1440 ( Constructor c )
1135 => FromUntaggedValue arity (C1 c U1)
1441 => FromUntaggedValue arity (C1 c U1)
1137− parseUntaggedValue opts _ (String s)
1443+ parseUntaggedValue (tname :* opts :* _) v =
1138− | s == pack (constructorTagModifier opts (conName (undefined :: t c U1 p))) =
1444+ contextCons cname tname $ case v of
1139− pure $ M1 U1
1446+ | tag == tag' -> pure $ M1 U1
1140− | otherwise =
1447+ | otherwise -> fail_ tag
1141− fail $ "Invalid tag: " ++ unpack s
1448+ _ -> typeMismatch "String" v
1142− parseUntaggedValue _ _ v = typeMismatch (conName (undefined :: t c U1 p)) v
1449+ where
1143−
1450+ tag' = pack $ constructorTagModifier opts cname
1144−
1451+ cname = conName (undefined :: M1 _i c _f _p)
1145−--------------------------------------------------------------------------------
1452+ fail_ tag = fail $
1146−
1453+ "expected tag " ++ show tag' ++ ", but found tag " ++ show tag
1147−notFound :: Text -> Parser a
1148−notFound key = fail $ "The key \"" ++ unpack key ++ "\" was not found"
1149−{-# INLINE notFound #-}
1151-------------------------------------------------------------------------------
1455-------------------------------------------------------------------------------
1152-- Instances
1456-- Instances
@@ -1209,14 +1513,15 @@ instance FromJSON Void where
1209 {-# INLINE parseJSON #-}
1513 {-# INLINE parseJSON #-}
1211instance FromJSON Bool where
1515instance FromJSON Bool where
1212− parseJSON = withBool "Bool" pure
1516+ parseJSON (Bool b) = pure b
1517+ parseJSON v = typeMismatch "Bool" v
1213 {-# INLINE parseJSON #-}
1518 {-# INLINE parseJSON #-}
1215instance FromJSONKey Bool where
1520instance FromJSONKey Bool where
1216 fromJSONKey = FromJSONKeyTextParser $ \t -> case t of
1521 fromJSONKey = FromJSONKeyTextParser $ \t -> case t of
1217 "true" -> pure True
1522 "true" -> pure True
1218 "false" -> pure False
1523 "false" -> pure False
1219− _ -> fail $ "Cannot parse key into Bool: " ++ T.unpack t
1524+ _ -> fail $ "cannot parse key " ++ show t ++ " into Bool"
1221instance FromJSON Ordering where
1526instance FromJSON Ordering where
1222 parseJSON = withText "Ordering" $ \s ->
1527 parseJSON = withText "Ordering" $ \s ->
@@ -1224,25 +1529,30 @@ instance FromJSON Ordering where
1224 "LT" -> return LT
1529 "LT" -> return LT
1225 "EQ" -> return EQ
1530 "EQ" -> return EQ
1226 "GT" -> return GT
1531 "GT" -> return GT
1532+ _ -> fail $ "parsing Ordering failed, unexpected " ++ show s ++
1227− _ -> fail "Parsing Ordering value failed: expected \"LT\", \"EQ\", or \"GT\""
1533+ " (expected \"LT\", \"EQ\", or \"GT\")"
1229instance FromJSON () where
1535instance FromJSON () where
1230 parseJSON = withArray "()" $ \v ->
1536 parseJSON = withArray "()" $ \v ->
1231 if V.null v
1537 if V.null v
1232 then pure ()
1538 then pure ()
1233− else fail "Expected an empty array"
1539+ else prependContext "()" $ fail "expected an empty array"
1234 {-# INLINE parseJSON #-}
1540 {-# INLINE parseJSON #-}
1236instance FromJSON Char where
1542instance FromJSON Char where
1237− parseJSON = withText "Char" $ \t ->
1543+ parseJSON = withText "Char" parseChar
1238− if T.compareLength t 1 == EQ
1239− then pure $ T.head t
1240− else fail "Expected a string of length 1"
1241 {-# INLINE parseJSON #-}
1544 {-# INLINE parseJSON #-}
1243− parseJSONList = withText "String" $ pure . T.unpack
1546+ parseJSONList (String s) = pure (T.unpack s)
1547+ parseJSONList v = typeMismatch "String" v
1244 {-# INLINE parseJSONList #-}
1548 {-# INLINE parseJSONList #-}
1550+parseChar :: Text -> Parser Char
1552+ if T.compareLength t 1 == EQ
1553+ then pure $ T.head t
1554+ else prependContext "Char" $ fail "expected a string of length 1"
1246instance FromJSON Double where
1556instance FromJSON Double where
1247 parseJSON = parseRealFloat "Double"
1557 parseJSON = parseRealFloat "Double"
1248 {-# INLINE parseJSON #-}
1558 {-# INLINE parseJSON #-}
@@ -1266,12 +1576,22 @@ instance FromJSONKey Float where
1266 _ -> Scientific.toRealFloat <$> parseScientificText t
1576 _ -> Scientific.toRealFloat <$> parseScientificText t
1268instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1578instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1579+ parseJSON (Number x)
1581+ , exp10 >= -1024 = return $! realToFrac x
1582+ | otherwise = prependContext "Ratio" $ fail msg
1584+ exp10 = base10Exponent x
1585+ msg = "found a number with exponent " ++ show exp10
1586+ ++ ", but it must not be greater than 1024 or less than -1024"
1587+ parseJSON o = objParser o
1269− parseJSON = withObject "Rational" $ \obj -> do
1589+ objParser = withObject "Rational" $ \obj -> do
1270− numerator <- obj .: "numerator"
1590+ numerator <- obj .: "numerator"
1271− denominator <- obj .: "denominator"
1591+ denominator <- obj .: "denominator"
1272− if denominator == 0
1592+ if denominator == 0
1273− then fail "Ratio denominator was 0"
1593+ then fail "Ratio denominator was 0"
1274− else pure $ numerator % denominator
1594+ else pure $ numerator % denominator
1275 {-# INLINE parseJSON #-}
1595 {-# INLINE parseJSON #-}
1277-- | This instance includes a bounds check to prevent maliciously
1597-- | This instance includes a bounds check to prevent maliciously
@@ -1279,7 +1599,7 @@ instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1279-- newtype 'Scientific' and provide your own instance using
1599-- newtype 'Scientific' and provide your own instance using
1280-- 'withScientific' if you want to allow larger inputs.
1600-- 'withScientific' if you want to allow larger inputs.
1281instance HasResolution a => FromJSON (Fixed a) where
1601instance HasResolution a => FromJSON (Fixed a) where
1282− parseJSON = withBoundedScientific "Fixed" $ pure . realToFrac
1602+ parseJSON = prependContext "Fixed" . withBoundedScientific' (pure . realToFrac)
1283 {-# INLINE parseJSON #-}
1603 {-# INLINE parseJSON #-}
1285instance FromJSON Int where
1605instance FromJSON Int where
@@ -1302,19 +1622,20 @@ instance FromJSONKey Integer where
1303instance FromJSON Natural where
1623instance FromJSON Natural where
1304 parseJSON value = do
1624 parseJSON value = do
1305− integer :: Integer <- parseIntegral "Natural" value
1625+ integer <- parseIntegral "Natural" value
1306− if integer < 0 then
1626+ parseNatural integer
1307− fail $ "expected Natural, encountered negative number " <> show integer
1309− pure $ fromIntegral integer
1311instance FromJSONKey Natural where
1628instance FromJSONKey Natural where
1312 fromJSONKey = FromJSONKeyTextParser $ \text -> do
1629 fromJSONKey = FromJSONKeyTextParser $ \text -> do
1313− integer :: Integer <- parseIntegralText "Natural" text
1630+ integer <- parseIntegralText "Natural" text
1631+ parseNatural integer
1633+parseNatural :: Integer -> Parser Natural
1634+parseNatural integer =
1314− if integer < 0 then
1635+ if integer < 0 then
1315− fail $ "expected Natural, encountered negative number " <> show integer
1636+ fail $ "parsing Natural failed, unexpected negative number " <> show integer
1317− pure $ fromIntegral integer
1638+ pure $ fromIntegral integer
1319instance FromJSON Int8 where
1640instance FromJSON Int8 where
1320 parseJSON = parseBoundedIntegral "Int8"
1641 parseJSON = parseBoundedIntegral "Int8"
@@ -1411,17 +1732,17 @@ parseVersionText = go . readP_to_S parseVersion . unpack
1412 go [(v,[])] = return v
1733 go [(v,[])] = return v
1413 go (_ : xs) = go xs
1734 go (_ : xs) = go xs
1414− go _ = fail "could not parse Version"
1735+ go _ = fail "parsing Version failed"
1416-------------------------------------------------------------------------------
1737-------------------------------------------------------------------------------
1417-- semigroups NonEmpty
1738-- semigroups NonEmpty
1418-------------------------------------------------------------------------------
1739-------------------------------------------------------------------------------
1420instance FromJSON1 NonEmpty where
1741instance FromJSON1 NonEmpty where
1421− liftParseJSON p _ = withArray "NonEmpty a" $
1742+ liftParseJSON p _ = withArray "NonEmpty" $
1422 (>>= ne) . Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1743 (>>= ne) . Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1424− ne [] = fail "Expected a NonEmpty but got an empty list"
1745+ ne [] = fail "parsing NonEmpty failed, unexpected empty list"
1425 ne (x:xs) = pure (x :| xs)
1746 ne (x:xs) = pure (x :| xs)
1426 {-# INLINE liftParseJSON #-}
1747 {-# INLINE liftParseJSON #-}
@@ -1442,7 +1763,7 @@ instance FromJSON Scientific where
1442-------------------------------------------------------------------------------
1763-------------------------------------------------------------------------------
1444instance FromJSON1 DList.DList where
1765instance FromJSON1 DList.DList where
1445− liftParseJSON p _ = withArray "DList a" $
1766+ liftParseJSON p _ = withArray "DList" $
1446 fmap DList.fromList .
1767 fmap DList.fromList .
1447 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1768 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1448 {-# INLINE liftParseJSON #-}
1769 {-# INLINE liftParseJSON #-}
@@ -1519,7 +1840,7 @@ instance (FromJSON1 f, FromJSON1 g) => FromJSON1 (Sum f g) where
1519 inr = "InR"
1840 inr = "InR"
1521 liftParseJSON _ _ _ = fail $
1842 liftParseJSON _ _ _ = fail $
1522− "expected an object with a single property " ++
1843+ "parsing Sum failed, expected an object with a single property " ++
1523 "where the property key should be either " ++
1844 "where the property key should be either " ++
1524 "\"InL\" or \"InR\""
1845 "\"InL\" or \"InR\""
1525 {-# INLINE liftParseJSON #-}
1846 {-# INLINE liftParseJSON #-}
@@ -1533,7 +1854,7 @@ instance (FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum f g a) where
1533-------------------------------------------------------------------------------
1854-------------------------------------------------------------------------------
1535instance FromJSON1 Seq.Seq where
1856instance FromJSON1 Seq.Seq where
1536− liftParseJSON p _ = withArray "Seq a" $
1857+ liftParseJSON p _ = withArray "Seq" $
1537 fmap Seq.fromList .
1858 fmap Seq.fromList .
1538 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1859 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
1539 {-# INLINE liftParseJSON #-}
1860 {-# INLINE liftParseJSON #-}
@@ -1567,13 +1888,13 @@ instance FromJSON a => FromJSON (IntMap.IntMap a) where
1568instance (FromJSONKey k, Ord k) => FromJSON1 (M.Map k) where
1889instance (FromJSONKey k, Ord k) => FromJSON1 (M.Map k) where
1569 liftParseJSON p _ = case fromJSONKey of
1890 liftParseJSON p _ = case fromJSONKey of
1570− FromJSONKeyCoerce _-> withObject "Map k v" $
1891+ FromJSONKeyCoerce _ -> withObject "Map" $
1571 fmap (H.foldrWithKey (M.insert . unsafeCoerce) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1892 fmap (H.foldrWithKey (M.insert . unsafeCoerce) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1572− FromJSONKeyText f -> withObject "Map k v" $
1893+ FromJSONKeyText f -> withObject "Map" $
1573 fmap (H.foldrWithKey (M.insert . f) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1894 fmap (H.foldrWithKey (M.insert . f) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1574− FromJSONKeyTextParser f -> withObject "Map k v" $
1895+ FromJSONKeyTextParser f -> withObject "Map" $
1575 H.foldrWithKey (\k v m -> M.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure M.empty)
1896 H.foldrWithKey (\k v m -> M.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure M.empty)
1576− FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1897+ FromJSONKeyValue f -> withArray "Map" $ \arr ->
1577 fmap M.fromList . Tr.sequence .
1898 fmap M.fromList . Tr.sequence .
1578 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
1899 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
1579 {-# INLINE liftParseJSON #-}
1900 {-# INLINE liftParseJSON #-}
@@ -1601,18 +1922,18 @@ instance (FromJSON v) => FromJSON (Tree.Tree v) where
1602instance FromJSON UUID.UUID where
1923instance FromJSON UUID.UUID where
1603 parseJSON = withText "UUID" $
1924 parseJSON = withText "UUID" $
1604− maybe (fail "Invalid UUID") pure . UUID.fromText
1925+ maybe (fail "invalid UUID") pure . UUID.fromText
1606instance FromJSONKey UUID.UUID where
1927instance FromJSONKey UUID.UUID where
1607 fromJSONKey = FromJSONKeyTextParser $
1928 fromJSONKey = FromJSONKeyTextParser $
1608− maybe (fail "Invalid UUID") pure . UUID.fromText
1929+ maybe (fail "invalid UUID") pure . UUID.fromText
1610-------------------------------------------------------------------------------
1931-------------------------------------------------------------------------------
1611-- vector
1932-- vector
1612-------------------------------------------------------------------------------
1933-------------------------------------------------------------------------------
1614instance FromJSON1 Vector where
1935instance FromJSON1 Vector where
1615− liftParseJSON p _ = withArray "Vector a" $
1936+ liftParseJSON p _ = withArray "Vector" $
1616 V.mapM (uncurry $ parseIndexedJSON p) . V.indexed
1937 V.mapM (uncurry $ parseIndexedJSON p) . V.indexed
1617 {-# INLINE liftParseJSON #-}
1938 {-# INLINE liftParseJSON #-}
@@ -1626,14 +1947,14 @@ vectorParseJSON s = withArray s $ fmap V.convert . V.mapM (uncurry $ parseIndexe
1626{-# INLINE vectorParseJSON #-}
1947{-# INLINE vectorParseJSON #-}
1628instance (Storable a, FromJSON a) => FromJSON (VS.Vector a) where
1949instance (Storable a, FromJSON a) => FromJSON (VS.Vector a) where
1629− parseJSON = vectorParseJSON "Data.Vector.Storable.Vector a"
1950+ parseJSON = vectorParseJSON "Data.Vector.Storable.Vector"
1631instance (VP.Prim a, FromJSON a) => FromJSON (VP.Vector a) where
1952instance (VP.Prim a, FromJSON a) => FromJSON (VP.Vector a) where
1632− parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector a"
1953+ parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector"
1633 {-# INLINE parseJSON #-}
1954 {-# INLINE parseJSON #-}
1635instance (VG.Vector VU.Vector a, FromJSON a) => FromJSON (VU.Vector a) where
1956instance (VG.Vector VU.Vector a, FromJSON a) => FromJSON (VU.Vector a) where
1636− parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector a"
1957+ parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector"
1637 {-# INLINE parseJSON #-}
1958 {-# INLINE parseJSON #-}
1639-------------------------------------------------------------------------------
1960-------------------------------------------------------------------------------
@@ -1647,13 +1968,13 @@ instance (Eq a, Hashable a, FromJSON a) => FromJSON (HashSet.HashSet a) where
1648instance (FromJSONKey k, Eq k, Hashable k) => FromJSON1 (H.HashMap k) where
1969instance (FromJSONKey k, Eq k, Hashable k) => FromJSON1 (H.HashMap k) where
1649 liftParseJSON p _ = case fromJSONKey of
1970 liftParseJSON p _ = case fromJSONKey of
1650− FromJSONKeyCoerce _ -> withObject "HashMap ~Text v" $
1971+ FromJSONKeyCoerce _ -> withObject "HashMap ~Text" $
1651 uc . H.traverseWithKey (\k v -> p v <?> Key k)
1972 uc . H.traverseWithKey (\k v -> p v <?> Key k)
1652− FromJSONKeyText f -> withObject "HashMap k v" $
1973+ FromJSONKeyText f -> withObject "HashMap" $
1653 fmap (mapKey f) . H.traverseWithKey (\k v -> p v <?> Key k)
1974 fmap (mapKey f) . H.traverseWithKey (\k v -> p v <?> Key k)
1654− FromJSONKeyTextParser f -> withObject "HashMap k v" $
1975+ FromJSONKeyTextParser f -> withObject "HashMap" $
1655 H.foldrWithKey (\k v m -> H.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure H.empty)
1976 H.foldrWithKey (\k v m -> H.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure H.empty)
1656− FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1977+ FromJSONKeyValue f -> withArray "Map" $ \arr ->
1657 fmap H.fromList . Tr.sequence .
1978 fmap H.fromList . Tr.sequence .
1658 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
1979 zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
@@ -1676,11 +1997,33 @@ instance FromJSON DotNetTime where
1676 parseJSON = withText "DotNetTime" $ \t ->
1997 parseJSON = withText "DotNetTime" $ \t ->
1677 let (s,m) = T.splitAt (T.length t - 5) t
1998 let (s,m) = T.splitAt (T.length t - 5) t
1678 t' = T.concat [s,".",m]
1999 t' = T.concat [s,".",m]
1679− in case parseTime defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
2000+ in case parseTimeM True defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
1680 Just d -> pure (DotNetTime d)
2001 Just d -> pure (DotNetTime d)
1681 _ -> fail "could not parse .NET time"
2002 _ -> fail "could not parse .NET time"
1682 {-# INLINE parseJSON #-}
2003 {-# INLINE parseJSON #-}
2005+-------------------------------------------------------------------------------
2007+-------------------------------------------------------------------------------
2009+instance FromJSON a => FromJSON (PM.Array a) where
2010+ -- note: we could do better than this if vector exposed the data
2011+ -- constructor in Data.Vector.
2012+ parseJSON = fmap Exts.fromList . parseJSON
2014+instance FromJSON a => FromJSON (PM.SmallArray a) where
2015+ parseJSON = fmap Exts.fromList . parseJSON
2017+#if MIN_VERSION_primitive(0,6,4)
2018+instance (PM.Prim a,FromJSON a) => FromJSON (PM.PrimArray a) where
2019+ parseJSON = fmap Exts.fromList . parseJSON
2021+#if !MIN_VERSION_primitive(0,7,0)
2022+instance (PM.PrimUnlifted a,FromJSON a) => FromJSON (PM.UnliftedArray a) where
2023+ parseJSON = fmap Exts.fromList . parseJSON
1684-------------------------------------------------------------------------------
2027-------------------------------------------------------------------------------
1686-------------------------------------------------------------------------------
2029-------------------------------------------------------------------------------
@@ -1748,6 +2091,40 @@ instance FromJSON DiffTime where
1748 parseJSON = withBoundedScientific "DiffTime" $ pure . realToFrac
2091 parseJSON = withBoundedScientific "DiffTime" $ pure . realToFrac
1749 {-# INLINE parseJSON #-}
2092 {-# INLINE parseJSON #-}
2094+instance FromJSON SystemTime where
2095+ parseJSON v = prependContext "SystemTime" $ do
2097+ let n' = floor (n * fromInteger (resolution n) :: Nano)
2098+ let (secs, nano) = n' `divMod` resolution n
2099+ return (MkSystemTime (fromInteger secs) (fromInteger nano))
2101+instance FromJSON CalendarDiffTime where
2102+ parseJSON = withObject "CalendarDiffTime" $ \obj -> CalendarDiffTime
2103+ <$> obj .: "months"
2106+instance FromJSON CalendarDiffDays where
2107+ parseJSON = withObject "CalendarDiffDays" $ \obj -> CalendarDiffDays
2108+ <$> obj .: "months"
2111+instance FromJSON DayOfWeek where
2112+ parseJSON = withText "DaysOfWeek" parseDayOfWeek
2114+parseDayOfWeek :: T.Text -> Parser DayOfWeek
2115+parseDayOfWeek t = case T.toLower t of
2116+ "monday" -> return Monday
2117+ "tuesday" -> return Tuesday
2118+ "wednesday" -> return Wednesday
2119+ "thursday" -> return Thursday
2120+ "friday" -> return Friday
2121+ "saturday" -> return Saturday
2122+ "sunday" -> return Sunday
2123+ _ -> fail "Invalid week day"
2125+instance FromJSONKey DayOfWeek where
2126+ fromJSONKey = FromJSONKeyTextParser parseDayOfWeek
1751-------------------------------------------------------------------------------
2128-------------------------------------------------------------------------------
1752-- base Monoid/Semigroup
2129-- base Monoid/Semigroup
1753-------------------------------------------------------------------------------
2130-------------------------------------------------------------------------------
@@ -1868,14 +2245,15 @@ instance FromJSON a => FromJSON (Semigroup.Option a) where
1869instance FromJSON1 Proxy where
2246instance FromJSON1 Proxy where
1870 {-# INLINE liftParseJSON #-}
2247 {-# INLINE liftParseJSON #-}
1871− liftParseJSON _ _ Null = pure Proxy
2248+ liftParseJSON _ _ = fromNull "Proxy" Proxy
1872− liftParseJSON _ _ v = typeMismatch "Proxy" v
1874instance FromJSON (Proxy a) where
2250instance FromJSON (Proxy a) where
1875 {-# INLINE parseJSON #-}
2251 {-# INLINE parseJSON #-}
1876− parseJSON Null = pure Proxy
2252+ parseJSON = fromNull "Proxy" Proxy
1877− parseJSON v = typeMismatch "Proxy" v
2254+fromNull :: String -> a -> Value -> Parser a
2255+fromNull _ a Null = pure a
2256+fromNull c _ v = prependContext c (typeMismatch "Null" v)
1880instance FromJSON2 Tagged where
2258instance FromJSON2 Tagged where
1881 liftParseJSON2 _ _ p _ = fmap Tagged . p
2259 liftParseJSON2 _ _ p _ = fmap Tagged . p
@@ -1902,10 +2280,7 @@ instance (FromJSON a, FromJSON b, FromJSON c) => FromJSONKey (a,b,c)
1902instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a,b,c,d)
2280instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a,b,c,d)
1904instance FromJSONKey Char where
2282instance FromJSONKey Char where
1905− fromJSONKey = FromJSONKeyTextParser $ \t ->
2283+ fromJSONKey = FromJSONKeyTextParser parseChar
1907− then return (T.index t 0)
1908− else typeMismatch "Expected Char but String didn't contain exactly one character" (String t)
1909 fromJSONKeyList = FromJSONKeyText T.unpack
2284 fromJSONKeyList = FromJSONKeyText T.unpack
1911instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where
2286instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where