@@ -1,29 +1,28 @@
1−{-# LANGUAGE CPP #-}
2−{-# LANGUAGE DataKinds #-}
3−{-# LANGUAGE DefaultSignatures #-}
4−{-# LANGUAGE FlexibleContexts #-}
5−{-# LANGUAGE FlexibleInstances #-}
6−{-# LANGUAGE GADTs #-}
1+{-# LANGUAGE CPP #-}
2+{-# LANGUAGE DataKinds #-}
3+{-# LANGUAGE DefaultSignatures #-}
4+{-# LANGUAGE FlexibleContexts #-}
5+{-# LANGUAGE FlexibleInstances #-}
6+{-# LANGUAGE GADTs #-}
77{-# LANGUAGE MultiParamTypeClasses #-}
8−{-# LANGUAGE NamedFieldPuns #-}
9−{-# LANGUAGE OverloadedStrings #-}
10−{-# LANGUAGE RecordWildCards #-}
11−{-# LANGUAGE ScopedTypeVariables #-}
12−{-# LANGUAGE TypeOperators #-}
13−{-# LANGUAGE TypeSynonymInstances #-}
14−{-# LANGUAGE UndecidableInstances #-}
15−{-# LANGUAGE ViewPatterns #-}
16−
17−#if __GLASGOW_HASKELL__ >= 706
18−{-# LANGUAGE PolyKinds #-}
19−#endif
20−
8+{-# LANGUAGE NoImplicitPrelude #-}
9+{-# LANGUAGE OverloadedStrings #-}
10+{-# LANGUAGE PolyKinds #-}
11+{-# LANGUAGE RecordWildCards #-}
12+{-# LANGUAGE ScopedTypeVariables #-}
13+{-# LANGUAGE TypeOperators #-}
14+{-# LANGUAGE TupleSections #-}
15+{-# LANGUAGE UndecidableInstances #-}
16+{-# LANGUAGE ViewPatterns #-}
17+
18+#include "incoherent-compat.h"
2119#include "overlapping-compat.h"
2220
2321-- TODO: Drop this when we remove support for Data.Attoparsec.Number
2422{-# OPTIONS_GHC -fno-warn-deprecations #-}
2523
26−module Data.Aeson.Types.FromJSON (
24+module Data.Aeson.Types.FromJSON
25+ (
2726 -- * Core JSON classes
2827 FromJSON(..)
2928 -- * Liftings to unary and binary type constructors
@@ -43,106 +42,121 @@ module Data.Aeson.Types.FromJSON (
4342 , coerceFromJSONKeyFunction
4443 , mapFromJSONKeyFunction
4544
45+ , GFromJSONKey()
46+ , genericFromJSONKey
47+
4648 -- * List functions
4749 , listParser
4850
49− -- * Inspecting @'Value's@
51+ -- * Inspecting @'Value's@
5052 , withObject
5153 , withText
5254 , withArray
53− , withNumber
5455 , withScientific
5556 , withBool
57+ , withEmbeddedJSON
5658
5759 -- * Functions
5860 , fromJSON
5961 , ifromJSON
62+ , typeMismatch
63+ , unexpected
64+ , parseField
65+ , parseFieldMaybe
66+ , parseFieldMaybe'
67+ , explicitParseField
68+ , explicitParseFieldMaybe
69+ , explicitParseFieldMaybe'
70+ , parseIndexedJSON
71+ -- ** Operators
6072 , (.:)
6173 , (.:?)
6274 , (.:!)
6375 , (.!=)
64− , typeMismatch
6576
6677 -- * Internal
6778 , parseOptionalFieldWith
6879 ) where
6980
70−import Prelude ()
71−import Prelude.Compat hiding (foldr)
81+import Prelude.Compat
7282
83+import Control.Applicative ((<|>), Const(..), liftA2)
84+import Control.Monad (zipWithM)
7385import Data.Aeson.Internal.Functions (mapKey)
86+import Data.Aeson.Parser.Internal (eitherDecodeWith, jsonEOF)
7487import Data.Aeson.Types.Generic
7588import Data.Aeson.Types.Internal
76−
77−import qualified Data.Aeson.Parser.Time as Time
78−import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly,
79− scientific)
80−
81−import Control.Applicative (Const (..), (<|>))
82−import Control.Monad ((<=<), zipWithM)
83−import Data.Attoparsec.Number (Number (..))
84−import Data.Bits (unsafeShiftR)
85−import Data.Fixed (Fixed, HasResolution)
86−import Data.Functor.Compose (Compose (..))
87−import Data.Functor.Identity (Identity (..))
88−import Data.Functor.Product (Product (..))
89−import Data.Functor.Sum (Sum (..))
90−import Data.Hashable (Hashable (..))
91−import Data.Int (Int16, Int32, Int64, Int8)
92−import Data.List.NonEmpty (NonEmpty (..))
93−import Data.Maybe (fromMaybe)
94−import Data.Monoid (Dual (..), First (..), Last (..), (<>))
95−import Data.Proxy (Proxy (..))
96−import Data.Ratio (Ratio, (%))
97−import Data.Scientific (Scientific)
98−import Data.Tagged (Tagged (..))
99−import Data.Text (Text, pack, unpack)
100−import Data.Time (Day, LocalTime, NominalDiffTime, TimeOfDay,
101− UTCTime, ZonedTime)
102−import Data.Time.Format (parseTime)
103−import Data.Time.Locale.Compat (defaultTimeLocale)
104−import Data.Traversable as Tr (sequence)
105−import Data.Vector (Vector)
106−import Data.Version (Version, parseVersion)
107−import Data.Word (Word16, Word32, Word64, Word8)
108−import Foreign.Storable (Storable)
89+import Data.Bits (unsafeShiftR)
90+import Data.Fixed (Fixed, HasResolution (resolution), Nano)
91+import Data.Functor.Compose (Compose(..))
92+import Data.Functor.Identity (Identity(..))
93+import Data.Functor.Product (Product(..))
94+import Data.Functor.Sum (Sum(..))
95+import Data.Hashable (Hashable(..))
96+import Data.Int (Int16, Int32, Int64, Int8)
97+import Data.List.NonEmpty (NonEmpty(..))
98+import Data.Maybe (fromMaybe)
99+import Data.Semigroup ((<>))
100+import Data.Proxy (Proxy(..))
101+import Data.Ratio ((%), Ratio)
102+import Data.Scientific (Scientific, base10Exponent)
103+import Data.Tagged (Tagged(..))
104+import Data.Text (Text, pack, unpack)
105+import Data.Time (Day, DiffTime, LocalTime, NominalDiffTime, TimeOfDay, UTCTime, ZonedTime)
106+import Data.Time.Calendar.Compat (CalendarDiffDays (..), DayOfWeek (..))
107+import Data.Time.LocalTime.Compat (CalendarDiffTime (..))
108+import Data.Time.Clock.System.Compat (SystemTime (..))
109+import Data.Time.Format.Compat (parseTimeM, defaultTimeLocale)
110+import Data.Traversable as Tr (sequence)
111+import Data.Vector (Vector)
112+import Data.Version (Version, parseVersion)
113+import Data.Void (Void)
114+import Data.Word (Word16, Word32, Word64, Word8)
115+import Foreign.Storable (Storable)
116+import Foreign.C.Types (CTime (..))
109117import GHC.Generics
110−import Numeric.Natural (Natural)
118+import Numeric.Natural (Natural)
111119import Text.ParserCombinators.ReadP (readP_to_S)
112−
113−import qualified Data.DList as DList
114−import qualified Data.HashMap.Strict as H
115−import qualified Data.HashSet as HashSet
116−import qualified Data.IntMap as IntMap
117−import qualified Data.IntSet as IntSet
118−import qualified Data.Map as M
119−import qualified Data.Scientific as Scientific
120−import qualified Data.Sequence as Seq
121−import qualified Data.Set as Set
122−import qualified Data.Text as T
123−import qualified Data.Text.Encoding as T
124−import qualified Data.Text.Lazy as LT
125−import qualified Data.Tree as Tree
126−import qualified Data.Vector as V
127−import qualified Data.Vector.Generic as VG
120+import Unsafe.Coerce (unsafeCoerce)
121+import qualified Data.Aeson.Parser.Time as Time
122+import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly, scientific)
123+import qualified Data.ByteString.Lazy as L
124+import qualified Data.DList as DList
125+import qualified Data.HashMap.Strict as H
126+import qualified Data.HashSet as HashSet
127+import qualified Data.IntMap as IntMap
128+import qualified Data.IntSet as IntSet
129+import qualified Data.Map as M
130+import qualified Data.Monoid as Monoid
131+import qualified Data.Scientific as Scientific
132+import qualified Data.Semigroup as Semigroup
133+import qualified Data.Sequence as Seq
134+import qualified Data.Set as Set
135+import qualified Data.Text as T
136+import qualified Data.Text.Encoding as T
137+import qualified Data.Text.Lazy as LT
138+import qualified Data.Tree as Tree
139+import qualified Data.UUID.Types as UUID
140+import qualified Data.Vector as V
141+import qualified Data.Vector.Generic as VG
128142import qualified Data.Vector.Primitive as VP
129−import qualified Data.Vector.Storable as VS
130−import qualified Data.Vector.Unboxed as VU
143+import qualified Data.Vector.Storable as VS
144+import qualified Data.Vector.Unboxed as VU
131145
132−import Unsafe.Coerce (unsafeCoerce)
146+import qualified GHC.Exts as Exts
147+import qualified Data.Primitive.Array as PM
148+import qualified Data.Primitive.SmallArray as PM
149+import qualified Data.Primitive.Types as PM
133150
134−#ifndef HAS_COERCIBLE
135−#define HAS_COERCIBLE (__GLASGOW_HASKELL__ >= 707)
151+#if MIN_VERSION_primitive(0,6,4)
152+#if !MIN_VERSION_primitive(0,7,0)
153+import qualified Data.Primitive.UnliftedArray as PM
136154#endif
155+import qualified Data.Primitive.PrimArray as PM
156+#endif
157+
137158
138−#if HAS_COERCIBLE
139159import Data.Coerce (Coercible, coerce)
140−coerce' :: Coercible a b => a -> b
141−coerce' = coerce
142−#else
143−coerce' :: a -> b
144−coerce' = unsafeCoerce
145−#endif
146160
147161parseIndexedJSON :: (Value -> Parser a) -> Int -> Value -> Parser a
148162parseIndexedJSON p idx value = p value <?> Index idx
@@ -151,7 +165,7 @@ parseIndexedJSON p idx value = p value <?> Index idx
151165parseIndexedJSONPair :: (Value -> Parser a) -> (Value -> Parser b) -> Int -> Value -> Parser (a, b)
152166parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
153167 where
154− p = withArray "(k,v)" $ \ab ->
168+ p = withArray "(k, v)" $ \ab ->
155169 let n = V.length ab
156170 in if n == 2
157171 then (,) <$> parseJSONElemAtIndex keyParser 0 ab
@@ -163,33 +177,57 @@ parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
163177parseJSONElemAtIndex :: (Value -> Parser a) -> Int -> V.Vector Value -> Parser a
164178parseJSONElemAtIndex p idx ary = p (V.unsafeIndex ary idx) <?> Index idx
165179
166−scientificToNumber :: Scientific -> Number
167−scientificToNumber s
168− | e < 0 = D $ Scientific.toRealFloat s
169− | otherwise = I $ c * 10 ^ e
170− where
171− e = Scientific.base10Exponent s
172− c = Scientific.coefficient s
173−{-# INLINE scientificToNumber #-}
174−
175180parseRealFloat :: RealFloat a => String -> Value -> Parser a
176−parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
177−parseRealFloat _ Null = pure (0/0)
178−parseRealFloat expected v = typeMismatch expected v
181+parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
182+parseRealFloat _ Null = pure (0/0)
183+parseRealFloat name v = prependContext name (unexpected v)
179184{-# INLINE parseRealFloat #-}
180185
186+parseIntegralFromScientific :: forall a. Integral a => Scientific -> Parser a
187+parseIntegralFromScientific s =
188+ case Scientific.floatingOrInteger s :: Either Double a of
189+ Right x -> pure x
190+ Left _ -> fail $ "unexpected floating number " ++ show s
191+{-# INLINE parseIntegralFromScientific #-}
192+
181193parseIntegral :: Integral a => String -> Value -> Parser a
182−parseIntegral expected = withScientific expected $ pure . truncate
194+parseIntegral name =
195+ prependContext name . withBoundedScientific' parseIntegralFromScientific
183196{-# INLINE parseIntegral #-}
184197
198+parseBoundedIntegralFromScientific :: (Bounded a, Integral a) => Scientific -> Parser a
199+parseBoundedIntegralFromScientific s = maybe
200+ (fail $ "value is either floating or will cause over or underflow " ++ show s)
201+ pure
202+ (Scientific.toBoundedInteger s)
203+{-# INLINE parseBoundedIntegralFromScientific #-}
204+
205+parseBoundedIntegral :: (Bounded a, Integral a) => String -> Value -> Parser a
206+parseBoundedIntegral name =
207+ prependContext name . withScientific' parseBoundedIntegralFromScientific
208+{-# INLINE parseBoundedIntegral #-}
209+
185210parseScientificText :: Text -> Parser Scientific
186211parseScientificText
187212 = either fail pure
188213 . A.parseOnly (A.scientific <* A.endOfInput)
189214 . T.encodeUtf8
190215
191−parseIntegralText :: Integral a => Text -> Parser a
192−parseIntegralText t = truncate <$> parseScientificText t
216+parseIntegralText :: Integral a => String -> Text -> Parser a
217+parseIntegralText name t =
218+ prependContext name $
219+ parseScientificText t
220+ >>= rejectLargeExponent
221+ >>= parseIntegralFromScientific
222+ where
223+ rejectLargeExponent :: Scientific -> Parser Scientific
224+ rejectLargeExponent s = withBoundedScientific' pure (Number s)
225+{-# INLINE parseIntegralText #-}
226+
227+parseBoundedIntegralText :: (Bounded a, Integral a) => String -> Text -> Parser a
228+parseBoundedIntegralText name t =
229+ prependContext name $
230+ parseScientificText t >>= parseBoundedIntegralFromScientific
193231
194232parseOptionalFieldWith :: (Value -> Parser (Maybe a))
195233 -> Object -> Text -> Parser (Maybe a)
@@ -249,14 +287,21 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
249287--
250288-- The basic ways to signal a failed conversion are as follows:
251289--
252−-- * '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;
292+--
293+-- * 'Control.Applicative.empty' (or 'Control.Monad.mzero') is uninformative:
294+-- use it when the error is meant to be caught by some @('<|>')@;
253295--
254−-- * 'fail' yields a custom error message
296+-- * 'typeMismatch' can be used to report a failure when the encountered value
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
299+-- implicit.
255300--
256−-- * 'typeMismatch' produces an informative message for cases when the
257−-- value encountered is not of the expected type
301+-- 'prependFailure' (or 'modifyFailure') add more information to a parser's
302+-- error messages.
258303--
259−-- An example type and instance:
304+-- An example type and instance using 'typeMismatch' and 'prependFailure':
260305--
261306-- @
262307-- \-- Allow ourselves to write 'Text' literals.
@@ -264,15 +309,30 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
264309--
265310-- data Coord = Coord { x :: Double, y :: Double }
266311--
267−-- instance FromJSON Coord where
268−-- parseJSON ('Object' v) = Coord '<$>'
269−-- v '.:' \"x\" '<*>'
270−-- v '.:' \"y\"
312+-- instance 'FromJSON' Coord where
313+-- 'parseJSON' ('Object' v) = Coord
314+-- '<$>' v '.:' \"x\"
315+-- '<*>' v '.:' \"y\"
271316--
272−-- \-- We do not expect a non-'Object' value here.
273−-- \-- We could use 'mzero' to fail, but 'typeMismatch'
274−-- \-- gives a much more informative error message.
275−-- parseJSON invalid = 'typeMismatch' \"Coord\" invalid
317+-- \-- We do not expect a non-'Object' value here.
318+-- \-- We could use 'Control.Applicative.empty' to fail, but 'typeMismatch'
319+-- \-- gives a much more informative error message.
320+-- 'parseJSON' invalid =
321+-- 'prependFailure' "parsing Coord failed, "
322+-- ('typeMismatch' \"Object\" invalid)
323+-- @
324+--
325+-- For this common case of only being concerned with a single
326+-- type of JSON value, the functions 'withObject', 'withScientific', etc.
327+-- are provided. Their use is to be preferred when possible, since
328+-- they are more terse. Using 'withObject', we can rewrite the above instance
329+-- (assuming the same language extension and data type) as:
330+--
331+-- @
332+-- instance 'FromJSON' Coord where
333+-- 'parseJSON' = 'withObject' \"Coord\" $ \\v -> Coord
334+-- '<$>' v '.:' \"x\"
335+-- '<*>' v '.:' \"y\"
276336-- @
277337--
278338-- Instead of manually writing your 'FromJSON' instance, there are two options
@@ -280,7 +340,7 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
280340--
281341-- * "Data.Aeson.TH" provides Template Haskell functions which will derive an
282342-- instance at compile time. The generated instance is optimized for your type
283−-- so will probably be more efficient than the following two options:
343+-- so it will probably be more efficient than the following option.
284344--
285345-- * The compiler can provide a default generic implementation for
286346-- 'parseJSON'.
@@ -298,18 +358,21 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
298358--
299359-- data Coord = Coord { x :: Double, y :: Double } deriving 'Generic'
300360--
301−-- instance FromJSON Coord
361+-- instance 'FromJSON' Coord
302362-- @
303363--
304−-- If @DefaultSignatures@ doesn't give exactly the results you want,
305−-- you can customize the generic decoding with only a tiny amount of
306−-- effort, using 'genericParseJSON' with your preferred 'Options':
364+-- The default implementation will be equivalent to
365+-- @parseJSON = 'genericParseJSON' 'defaultOptions'@; if you need different
366+-- options, you can customize the generic decoding by defining:
307367--
308368-- @
309−-- instance FromJSON Coord where
310−-- parseJSON = 'genericParseJSON' 'defaultOptions'
369+-- customOptions = 'defaultOptions'
370+-- { 'fieldLabelModifier' = 'map' 'Data.Char.toUpper'
371+-- }
372+--
373+-- instance 'FromJSON' Coord where
374+-- 'parseJSON' = 'genericParseJSON' customOptions
311375-- @
312−
313376class FromJSON a where
314377 parseJSON :: Value -> Parser a
315378
@@ -317,13 +380,11 @@ class FromJSON a where
317380 parseJSON = genericParseJSON defaultOptions
318381
319382 parseJSONList :: Value -> Parser [a]
320− parseJSONList (Array a)
321− = zipWithM (parseIndexedJSON parseJSON) [0..]
383+ parseJSONList = withArray "[]" $ \a ->
384+ zipWithM (parseIndexedJSON parseJSON) [0..]
322385 . V.toList
323386 $ a
324387
325− parseJSONList v = typeMismatch "[a]" v
326−
327388-------------------------------------------------------------------------------
328389-- Classes and types for map keys
329390-------------------------------------------------------------------------------
@@ -335,6 +396,16 @@ class FromJSON a where
335396-- > newtype SomeId = SomeId { getSomeId :: Text }
336397-- > deriving (Eq,Ord,Hashable,FromJSONKey)
337398--
399+-- If you have a sum of nullary constructors, you may use the generic
400+-- implementation:
401+--
402+-- @
403+-- data Color = Red | Green | Blue
404+-- deriving Generic
405+--
406+-- instance 'FromJSONKey' Color where
407+-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
408+-- @
338409class FromJSONKey a where
339410 -- | Strategy for parsing the key of a map-like container.
340411 fromJSONKey :: FromJSONKeyFunction a
@@ -357,11 +428,7 @@ class FromJSONKey a where
357428-- At the moment this type is intentionally not exported. 'FromJSONKeyFunction'
358429-- can be inspected, but cannot be constructed.
359430data CoerceText a where
360−#if HAS_COERCIBLE
361431 CoerceText :: Coercible Text a => CoerceText a
362−#else
363− CoerceText :: CoerceText a
364−#endif
365432
366433-- | This type is related to 'ToJSONKeyFunction'. If 'FromJSONKeyValue' is used in the
367434-- 'FromJSONKey' instance, then 'ToJSONKeyValue' should be used in the 'ToJSONKey'
@@ -381,7 +448,7 @@ data FromJSONKeyFunction a
381448
382449-- | Only law abiding up to interpretation
383450instance Functor FromJSONKeyFunction where
384− fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce')
451+ fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce)
385452 fmap h (FromJSONKeyText f) = FromJSONKeyText (h . f)
386453 fmap h (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap h . f)
387454 fmap h (FromJSONKeyValue f) = FromJSONKeyValue (fmap h . f)
@@ -395,9 +462,7 @@ instance Functor FromJSONKeyFunction where
395462--
396463-- On pre GHC 7.8 this is unconstrainted function.
397464fromJSONKeyCoerce ::
398−#if HAS_COERCIBLE
399465 Coercible Text a =>
400−#endif
401466 FromJSONKeyFunction a
402467fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
403468
@@ -405,60 +470,91 @@ fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
405470--
406471-- See note on 'fromJSONKeyCoerce'.
407472coerceFromJSONKeyFunction ::
408−#if HAS_COERCIBLE
409473 Coercible a b =>
410−#endif
411474 FromJSONKeyFunction a -> FromJSONKeyFunction b
412−#if HAS_COERCIBLE
413475coerceFromJSONKeyFunction = coerce
414−#else
415−coerceFromJSONKeyFunction (FromJSONKeyCoerce CoerceText) = FromJSONKeyCoerce CoerceText
416−coerceFromJSONKeyFunction (FromJSONKeyText f) = FromJSONKeyText (coerce' . f)
417−coerceFromJSONKeyFunction (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap coerce' . f)
418−coerceFromJSONKeyFunction (FromJSONKeyValue f) = FromJSONKeyValue (fmap coerce' . f)
419−#endif
420476
421477{-# RULES
422478 "FromJSONKeyCoerce: fmap id" forall (x :: FromJSONKeyFunction a).
423479 fmap id x = x
424480 #-}
425−#if HAS_COERCIBLE
426481{-# RULES
427482 "FromJSONKeyCoerce: fmap coerce" forall x .
428483 fmap coerce x = coerceFromJSONKeyFunction x
429484 #-}
430−#endif
431485
432486-- | Same as 'fmap'. Provided for the consistency with 'ToJSONKeyFunction'.
433487mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b
434488mapFromJSONKeyFunction = fmap
435489
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.
493+--
494+-- See also 'genericToJSONKey'.
495+--
496+-- === __Example__
497+--
498+-- @
499+-- data Color = Red | Green | Blue
500+-- deriving 'Generic'
501+--
502+-- instance 'FromJSONKey' Color where
503+-- 'fromJSONKey' = 'genericFromJSONKey' 'defaultJSONKeyOptions'
504+-- @
505+genericFromJSONKey :: forall a. (Generic a, GFromJSONKey (Rep a))
506+ => JSONKeyOptions
507+ -> FromJSONKeyFunction a
508+genericFromJSONKey opts = FromJSONKeyTextParser $ \t ->
509+ case parseSumFromString (keyModifier opts) t of
510+ Nothing -> fail $
511+ "invalid key " ++ show t ++ ", expected one of " ++ show cnames
512+ Just k -> pure (to k)
513+ where
514+ cnames = unTagged2 (constructorTags (keyModifier opts) :: Tagged2 (Rep a) [String])
515+
516+class (ConstructorNames f, SumFromString f) => GFromJSONKey f where
517+instance (ConstructorNames f, SumFromString f) => GFromJSONKey f where
518+
436519-------------------------------------------------------------------------------
437520-- Functions needed for documentation
438521-------------------------------------------------------------------------------
439522
440523-- | Fail parsing due to a type mismatch, with a descriptive message.
441524--
442−-- Example usage:
525+-- The following wrappers should generally be prefered:
526+-- 'withObject', 'withArray', 'withText', 'withBool'.
443527--
444−-- @
445−-- instance FromJSON Coord where
446−-- parseJSON ('Object' v) = {- type matches, life is good -}
447−-- parseJSON wat = 'typeMismatch' \"Coord\" wat
448−-- @
449−typeMismatch :: String -- ^ The name of the type you are trying to parse.
528+-- ==== Error message example
529+--
530+-- > typeMismatch "Object" (String "oops")
531+-- > -- Error: "expected Object, but encountered String"
532+typeMismatch :: String -- ^ The name of the JSON type being parsed
533+ -- (@\"Object\"@, @\"Array\"@, @\"String\"@, @\"Number\"@,
534+ -- @\"Boolean\"@, or @\"Null\"@).
450535 -> Value -- ^ The actual value encountered.
451536 -> Parser a
452537typeMismatch expected actual =
453− fail $ "expected " ++ expected ++ ", encountered " ++ name
454− where
455− name = case actual of
456− Object _ -> "Object"
457− Array _ -> "Array"
458− String _ -> "String"
459− Number _ -> "Number"
460− Bool _ -> "Boolean"
461− Null -> "Null"
538+ fail $ "expected " ++ expected ++ ", but encountered " ++ typeOf actual
539+
540+-- | Fail parsing due to a type mismatch, when the expected types are implicit.
541+--
542+-- ==== Error message example
543+--
544+-- > unexpected (String "oops")
545+-- > -- Error: "unexpected String"
546+unexpected :: Value -> Parser a
547+unexpected actual = fail $ "unexpected " ++ typeOf actual
548+
549+-- | JSON type of a value, name of the head constructor.
550+typeOf :: Value -> String
551+typeOf v = case v of
552+ Object _ -> "Object"
553+ Array _ -> "Array"
554+ String _ -> "String"
555+ Number _ -> "Number"
556+ Bool _ -> "Boolean"
557+ Null -> "Null"
462558
463559-------------------------------------------------------------------------------
464560-- Lifings of FromJSON and ToJSON to unary and binary type constructors
@@ -471,7 +567,7 @@ typeMismatch expected actual =
471567--
472568-- * "Data.Aeson.TH" provides Template Haskell functions which will derive an
473569-- instance at compile time. The generated instance is optimized for your type
474−-- so will probably be more efficient than the following two options:
570+-- so it will probably be more efficient than the following option.
475571--
476572-- * The compiler can provide a default generic implementation for
477573-- 'liftParseJSON'.
@@ -489,16 +585,20 @@ typeMismatch expected actual =
489585--
490586-- data Pair a b = Pair { pairFst :: a, pairSnd :: b } deriving 'Generic1'
491587--
492−-- instance FromJSON a => FromJSON1 (Pair a)
588+-- instance 'FromJSON' a => 'FromJSON1' (Pair a)
493589-- @
494590--
495−-- If @DefaultSignatures@ doesn't give exactly the results you want,
591+-- If the default implementation doesn't give exactly the results you want,
496592-- you can customize the generic decoding with only a tiny amount of
497593-- effort, using 'genericLiftParseJSON' with your preferred 'Options':
498594--
499595-- @
500−-- instance FromJSON a => FromJSON1 (Pair a) where
501−-- liftParseJSON = 'genericLiftParseJSON' 'defaultOptions'
596+-- customOptions = 'defaultOptions'
597+-- { 'fieldLabelModifier' = 'map' 'Data.Char.toUpper'
598+-- }
599+--
600+-- instance 'FromJSON' a => 'FromJSON1' (Pair a) where
601+-- 'liftParseJSON' = 'genericLiftParseJSON' customOptions
502602-- @
503603class FromJSON1 f where
504604 liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
@@ -535,9 +635,8 @@ class FromJSON2 f where
535635 -> (Value -> Parser b)
536636 -> (Value -> Parser [b])
537637 -> Value -> Parser [f a b]
538− liftParseJSONList2 fa ga fb gb v = case v of
539− Array vals -> fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
540− _ -> typeMismatch "[a]" v
638+ liftParseJSONList2 fa ga fb gb = withArray "[]" $ \vals ->
639+ fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
541640
542641-- | Lift the standard 'parseJSON' function through the type constructor.
543642parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
@@ -551,7 +650,7 @@ parseJSON2 = liftParseJSON2 parseJSON parseJSONList parseJSON parseJSONList
551650-- | Helper function to use with 'liftParseJSON'. See 'Data.Aeson.ToJSON.listEncoding'.
552651listParser :: (Value -> Parser a) -> Value -> Parser [a]
553652listParser f (Array xs) = fmap V.toList (V.mapM f xs)
554−listParser _ v = typeMismatch "[a]" v
653+listParser _ v = typeMismatch "Array" v
555654{-# INLINE listParser #-}
556655
557656-------------------------------------------------------------------------------
@@ -569,48 +668,139 @@ instance (FromJSON a) => FromJSON [a] where
569668-- Functions
570669-------------------------------------------------------------------------------
571670
572−-- | @withObject expected f value@ applies @f@ to the 'Object' when @value@ is an @Object@
573−-- and fails using @'typeMismatch' expected@ otherwise.
671+-- | Add context to a failure message, indicating the name of the structure
672+-- being parsed.
673+--
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, ")
678+
679+-- | @'withObject' name f value@ applies @f@ to the 'Object' when @value@
680+-- is an 'Data.Aeson.Object' and fails otherwise.
681+--
682+-- ==== Error message example
683+--
684+-- > withObject "MyType" f (String "oops")
685+-- > -- Error: "parsing MyType failed, expected Object, but encountered String"
574686withObject :: String -> (Object -> Parser a) -> Value -> Parser a
575−withObject _ f (Object obj) = f obj
576−withObject expected _ v = typeMismatch expected v
687+withObject _ f (Object obj) = f obj
688+withObject name _ v = prependContext name (typeMismatch "Object" v)
577689{-# INLINE withObject #-}
578690
579−-- | @withText expected f value@ applies @f@ to the 'Text' when @value@ is a @String@
580−-- and fails using @'typeMismatch' expected@ otherwise.
691+-- | @'withText' name f value@ applies @f@ to the 'Text' when @value@ is a
692+-- 'Data.Aeson.String' and fails otherwise.
693+--
694+-- ==== Error message example
695+--
696+-- > withText "MyType" f Null
697+-- > -- Error: "parsing MyType failed, expected String, but encountered Null"
581698withText :: String -> (Text -> Parser a) -> Value -> Parser a
582−withText _ f (String txt) = f txt
583−withText expected _ v = typeMismatch expected v
699+withText _ f (String txt) = f txt
700+withText name _ v = prependContext name (typeMismatch "String" v)
584701{-# INLINE withText #-}
585702
586−-- | @withArray expected f value@ applies @f@ to the 'Array' when @value@ is an @Array@
587−-- and fails using @'typeMismatch' expected@ otherwise.
703+-- | @'withArray' expected f value@ applies @f@ to the 'Array' when @value@ is
704+-- an 'Data.Aeson.Array' and fails otherwise.
705+--
706+-- ==== Error message example
707+--
708+-- > withArray "MyType" f (String "oops")
709+-- > -- Error: "parsing MyType failed, expected Array, but encountered String"
588710withArray :: String -> (Array -> Parser a) -> Value -> Parser a
589−withArray _ f (Array arr) = f arr
590−withArray expected _ v = typeMismatch expected v
711+withArray _ f (Array arr) = f arr
712+withArray name _ v = prependContext name (typeMismatch "Array" v)
591713{-# INLINE withArray #-}
592714
593−-- | @withNumber expected f value@ applies @f@ to the 'Number' when @value@ is a 'Number'.
594−-- and fails using @'typeMismatch' expected@ otherwise.
595−withNumber :: String -> (Number -> Parser a) -> Value -> Parser a
596−withNumber expected f = withScientific expected (f . scientificToNumber)
597−{-# INLINE withNumber #-}
598−{-# DEPRECATED withNumber "Use withScientific instead" #-}
599−
600−-- | @withScientific expected f value@ applies @f@ to the 'Scientific' number when @value@ is a 'Number'.
601−-- and fails using @'typeMismatch' expected@ otherwise.
715+-- | @'withScientific' name f value@ applies @f@ to the 'Scientific' number
716+-- when @value@ is a 'Data.Aeson.Number' and fails using 'typeMismatch'
717+-- otherwise.
718+--
719+-- /Warning/: If you are converting from a scientific to an unbounded
720+-- type such as 'Integer' you may want to add a restriction on the
721+-- size of the exponent (see 'withBoundedScientific') to prevent
722+-- malicious input from filling up the memory of the target system.
723+--
724+-- ==== Error message example
725+--
726+-- > withScientific "MyType" f (String "oops")
727+-- > -- Error: "parsing MyType failed, expected Number, but encountered String"
602728withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
603−withScientific _ f (Number scientific) = f scientific
604−withScientific expected _ v = typeMismatch expected v
729+withScientific _ f (Number scientific) = f scientific
730+withScientific name _ v = prependContext name (typeMismatch "Number" v)
605731{-# INLINE withScientific #-}
606732
607−-- | @withBool expected f value@ applies @f@ to the 'Bool' when @value@ is a @Bool@
608−-- and fails using @'typeMismatch' expected@ otherwise.
733+-- | A variant of 'withScientific' which doesn't use 'prependContext', so that
734+-- such context can be added separately in a way that also applies when the
735+-- continuation @f :: Scientific -> Parser a@ fails.
736+--
737+-- /Warning/: If you are converting from a scientific to an unbounded
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.
741+--
742+-- ==== Error message examples
743+--
744+-- > withScientific' f (String "oops")
745+-- > -- Error: "unexpected String"
746+-- >
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
751+ Number n -> f n
752+ _ -> typeMismatch "Number" v
753+{-# INLINE withScientific' #-}
754+
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.
757+withBoundedScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
758+withBoundedScientific name f v = withBoundedScientific_ (prependContext name) f v
759+{-# INLINE withBoundedScientific #-}
760+
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' #-}
767+
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) =
772+ if exp10 > 1024
773+ then whenFail (fail msg)
774+ else f scientific
775+ where
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_ #-}
781+
782+-- | @'withBool' expected f value@ applies @f@ to the 'Bool' when @value@ is a
783+-- 'Boolean' and fails otherwise.
784+--
785+-- ==== Error message example
786+--
787+-- > withBool "MyType" f (String "oops")
788+-- > -- Error: "parsing MyType failed, expected Boolean, but encountered String"
609789withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
610−withBool _ f (Bool arr) = f arr
611−withBool expected _ v = typeMismatch expected v
790+withBool _ f (Bool arr) = f arr
791+withBool name _ v = prependContext name (typeMismatch "Boolean" v)
612792{-# INLINE withBool #-}
613793
794+-- | Decode a nested JSON-encoded string.
795+withEmbeddedJSON :: String -> (Value -> Parser a) -> Value -> Parser a
796+withEmbeddedJSON _ innerParser (String txt) =
797+ either fail innerParser $ eitherDecode (L.fromStrict $ T.encodeUtf8 txt)
798+ where
799+ eitherDecode = eitherFormatError . eitherDecodeWith jsonEOF ifromJSON
800+ eitherFormatError = either (Left . uncurry formatError) Right
801+withEmbeddedJSON name _ v = prependContext name (typeMismatch "String" v)
802+{-# INLINE withEmbeddedJSON #-}
803+
614804-- | Convert a value from JSON, failing if the types do not match.
615805fromJSON :: (FromJSON a) => Value -> Result a
616806fromJSON = parse parseJSON
@@ -629,32 +819,68 @@ ifromJSON = iparse parseJSON
629819-- in an object for it to be valid. If the key and value are
630820-- optional, use '.:?' instead.
631821(.:) :: (FromJSON a) => Object -> Text -> Parser a
632−obj .: key = case H.lookup key obj of
633− Nothing -> fail $ "key " ++ show key ++ " not present"
634− Just v -> parseJSON v <?> Key key
822+(.:) = explicitParseField parseJSON
635823{-# INLINE (.:) #-}
636824
637−-- | Retrieve the value associated with the given key of an 'Object'.
638−-- The result is 'Nothing' if the key is not present, or 'empty' if
639−-- the value cannot be converted to the desired type.
825+-- | Retrieve the value associated with the given key of an 'Object'. The
826+-- result is 'Nothing' if the key is not present or if its value is 'Null',
827+-- or 'empty' if the value cannot be converted to the desired type.
640828--
641829-- This accessor is most useful if the key and value can be absent
642830-- from an object without affecting its validity. If the key and
643831-- value are mandatory, use '.:' instead.
644832(.:?) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
645−obj .:? key = case H.lookup key obj of
646− Nothing -> pure Nothing
647− Just v -> parseJSON v <?> Key key
833+(.:?) = explicitParseFieldMaybe parseJSON
648834{-# INLINE (.:?) #-}
649835
650−-- | Like '.:?', but the resulting parser will fail,
651−-- if the key is present but is 'Null'.
836+-- | Retrieve the value associated with the given key of an 'Object'.
837+-- The result is 'Nothing' if the key is not present or 'empty' if the
838+-- value cannot be converted to the desired type.
839+--
840+-- This differs from '.:?' by attempting to parse 'Null' the same as any
841+-- other JSON value, instead of interpreting it as 'Nothing'.
652842(.:!) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
653−obj .:! key = case H.lookup key obj of
654− Nothing -> pure Nothing
655− Just v -> Just <$> parseJSON v <?> Key key
843+(.:!) = explicitParseFieldMaybe' parseJSON
656844{-# INLINE (.:!) #-}
657845
846+-- | Function variant of '.:'.
847+parseField :: (FromJSON a) => Object -> Text -> Parser a
848+parseField = (.:)
849+{-# INLINE parseField #-}
850+
851+-- | Function variant of '.:?'.
852+parseFieldMaybe :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
853+parseFieldMaybe = (.:?)
854+{-# INLINE parseFieldMaybe #-}
855+
856+-- | Function variant of '.:!'.
857+parseFieldMaybe' :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
858+parseFieldMaybe' = (.:!)
859+{-# INLINE parseFieldMaybe' #-}
860+
861+-- | Variant of '.:' with explicit parser function.
862+--
863+-- E.g. @'explicitParseField' 'parseJSON1' :: ('FromJSON1' f, 'FromJSON' a) -> 'Object' -> 'Text' -> 'Parser' (f a)@
864+explicitParseField :: (Value -> Parser a) -> Object -> Text -> Parser a
865+explicitParseField p obj key = case H.lookup key obj of
866+ Nothing -> fail $ "key " ++ show key ++ " not found"
867+ Just v -> p v <?> Key key
868+{-# INLINE explicitParseField #-}
869+
870+-- | Variant of '.:?' with explicit parser function.
871+explicitParseFieldMaybe :: (Value -> Parser a) -> Object -> Text -> Parser (Maybe a)
872+explicitParseFieldMaybe p obj key = case H.lookup key obj of
873+ Nothing -> pure Nothing
874+ Just v -> liftParseJSON p (listParser p) v <?> Key key -- listParser isn't used by maybe instance.
875+{-# INLINE explicitParseFieldMaybe #-}
876+
877+-- | Variant of '.:!' with explicit parser function.
878+explicitParseFieldMaybe' :: (Value -> Parser a) -> Object -> Text -> Parser (Maybe a)
879+explicitParseFieldMaybe' p obj key = case H.lookup key obj of
880+ Nothing -> pure Nothing
881+ Just v -> Just <$> p v <?> Key key
882+{-# INLINE explicitParseFieldMaybe' #-}
883+
658884-- | Helper for use in combination with '.:?' to provide default
659885-- values for optional JSON object fields.
660886--
@@ -677,11 +903,47 @@ pmval .!= val = fromMaybe val <$> pmval
677903-- Generic parseJSON
678904-------------------------------------------------------------------------------
679905
906+instance GFromJSON arity V1 where
907+ -- Whereof we cannot format, thereof we cannot parse:
908+ gParseJSON _ _ _ = fail "Attempted to parse empty type"
909+
910+
680911instance OVERLAPPABLE_ (GFromJSON arity a) => GFromJSON arity (M1 i c a) where
681912 -- Meta-information, which is not handled elsewhere, is just added to the
682913 -- parsed value:
683914 gParseJSON opts fargs = fmap M1 . gParseJSON opts fargs
684915
916+-- Information for error messages
917+
918+type TypeName = String
919+type ConName = String
920+
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
924+
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 ++ ", ")
934+
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)
938+
939+-- | Render a constructor as @\"MyType(MyConstructor)\"@.
940+showCons :: ConName -> TypeName -> String
941+showCons cname tname = tname ++ "(" ++ cname ++ ")"
942+
943+--------------------------------------------------------------------------------
944+
945+-- Parsing single fields
946+
685947instance (FromJSON a) => GFromJSON arity (K1 i a) where
686948 -- Constant values are decoded using their FromJSON instance:
687949 gParseJSON _opts _ = fmap K1 . parseJSON
@@ -696,327 +958,499 @@ instance (FromJSON1 f) => GFromJSON One (Rec1 f) where
696958 -- FromJSON1 instance:
697959 gParseJSON _opts (From1Args pj pjl) = fmap Rec1 . liftParseJSON pj pjl
698960
699−instance GFromJSON arity U1 where
700− -- Empty constructors are expected to be encoded as an empty array:
701− gParseJSON _opts _ v
702− | isEmptyArray v = pure U1
703− | otherwise = typeMismatch "unit constructor (U1)" v
704−
705−instance (ConsFromJSON arity a) => GFromJSON arity (C1 c a) where
706− -- Constructors need to be decoded differently depending on whether they're
707− -- a record or not. This distinction is made by consParseJSON:
708− gParseJSON opts fargs = fmap M1 . consParseJSON opts fargs
709−
710−instance ( FromProduct arity a, FromProduct arity b
711− , ProductSize a, ProductSize b
712− ) => GFromJSON arity (a :*: b) where
713− -- Products are expected to be encoded to an array. Here we check whether we
714− -- got an array of the same size as the product, then parse each of the
715− -- product's elements using parseProduct:
716− gParseJSON opts fargs = withArray "product (:*:)" $ \arr ->
717− let lenArray = V.length arr
718− lenProduct = (unTagged2 :: Tagged2 (a :*: b) Int -> Int)
719− productSize in
720− if lenArray == lenProduct
721− then parseProduct opts fargs arr 0 lenProduct
722− else fail $ "When expecting a product of " ++ show lenProduct ++
723− " values, encountered an Array of " ++ show lenArray ++
724− " elements instead"
725−
726−instance ( AllNullary (a :+: b) allNullary
727− , ParseSum arity (a :+: b) allNullary
728− ) => GFromJSON arity (a :+: b) where
729− -- If all constructors of a sum datatype are nullary and the
730− -- 'allNullaryToStringTag' option is set they are expected to be
731− -- encoded as strings. This distinction is made by 'parseSum':
732− gParseJSON opts fargs =
733− (unTagged :: Tagged allNullary (Parser ((a :+: b) d)) ->
734− Parser ((a :+: b) d))
735− . parseSum opts fargs
736−
737961instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
738962 -- If an occurrence of the last type parameter is nested inside two
739963 -- composed types, it is decoded by using the outermost type's FromJSON1
740964 -- instance to generically decode the innermost type:
741965 gParseJSON opts fargs =
742− let gpj = gParseJSON opts fargs in
743− fmap Comp1 . liftParseJSON gpj (listParser gpj)
966+ let gpj = gParseJSON opts fargs in
967+ fmap Comp1 . liftParseJSON gpj (listParser gpj)
968+
969+--------------------------------------------------------------------------------
970+
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
973+ -- parsed value:
974+ gParseJSON opts fargs = fmap M1 . gParseJSON' (tname :* opts :* fargs)
975+ where
976+ tname = moduleName proxy ++ "." ++ datatypeName proxy
977+ proxy = undefined :: M1 _i d _f _p
978+
979+-- | 'GFromJSON', after unwrapping the 'D1' constructor, now carrying the data
980+-- type's name.
981+class GFromJSON' arity f where
982+ gParseJSON' :: TypeName :* Options :* FromArgs arity a
983+ -> Value
984+ -> Parser (f a)
985+
986+-- | Single constructor.
987+instance ( ConsFromJSON arity a
988+ , AllNullary (C1 c a) allNullary
989+ , ParseSum arity (C1 c a) allNullary
990+ , Constructor c
991+ ) => GFromJSON' arity (C1 c a) where
992+ -- The option 'tagSingleConstructors' determines whether to wrap
993+ -- a single-constructor type.
994+ gParseJSON' p@(_ :* opts :* _)
995+ | tagSingleConstructors opts
996+ = (unTagged :: Tagged allNullary (Parser (C1 c a p)) -> Parser (C1 c a p))
997+ . parseSum p
998+ | otherwise = fmap M1 . consParseJSON (cname :* p)
999+ where
1000+ cname = conName (undefined :: M1 _i c _f _p)
1001+
1002+-- | Multiple constructors.
1003+instance ( AllNullary (a :+: b) allNullary
1004+ , ParseSum arity (a :+: b) allNullary
1005+ ) => GFromJSON' arity (a :+: b) where
1006+ -- If all constructors of a sum datatype are nullary and the
1007+ -- 'allNullaryToStringTag' option is set they are expected to be
1008+ -- encoded as strings. This distinction is made by 'parseSum':
1009+ gParseJSON' p =
1010+ (unTagged :: Tagged allNullary (Parser ((a :+: b) _d)) ->
1011+ Parser ((a :+: b) _d))
1012+ . parseSum p
7441013
7451014--------------------------------------------------------------------------------
7461015
7471016class ParseSum arity f allNullary where
748− parseSum :: Options -> FromArgs arity a
749− -> Value -> Tagged allNullary (Parser (f a))
750−
751−instance ( SumFromString (a :+: b)
752− , FromPair arity (a :+: b)
753− , FromTaggedObject arity (a :+: b)
754− , FromUntaggedValue arity (a :+: b)
755− ) => ParseSum arity (a :+: b) True where
756− parseSum opts fargs
757− | allNullaryToStringTag opts = Tagged . parseAllNullarySum opts
758− | otherwise = Tagged . parseNonAllNullarySum opts fargs
759−
760−instance ( FromPair arity (a :+: b)
761− , FromTaggedObject arity (a :+: b)
762− , FromUntaggedValue arity (a :+: b)
763− ) => ParseSum arity (a :+: b) False where
764− parseSum opts fargs = Tagged . parseNonAllNullarySum opts fargs
1017+ parseSum :: TypeName :* Options :* FromArgs arity a
1018+ -> Value
1019+ -> Tagged allNullary (Parser (f a))
1020+
1021+instance ( ConstructorNames f
1022+ , SumFromString f
1023+ , FromPair arity f
1024+ , FromTaggedObject arity f
1025+ , FromUntaggedValue arity f
1026+ ) => ParseSum arity f True where
1027+ parseSum p@(tname :* opts :* _)
1028+ | allNullaryToStringTag opts = Tagged . parseAllNullarySum tname opts
1029+ | otherwise = Tagged . parseNonAllNullarySum p
1030+
1031+instance ( ConstructorNames f
1032+ , FromPair arity f
1033+ , FromTaggedObject arity f
1034+ , FromUntaggedValue arity f
1035+ ) => ParseSum arity f False where
1036+ parseSum p = Tagged . parseNonAllNullarySum p
7651037
7661038--------------------------------------------------------------------------------
7671039
768−parseAllNullarySum :: SumFromString f => Options -> Value -> Parser (f a)
769−parseAllNullarySum opts = withText "Text" $ \key ->
770− maybe (notFound key) return $
771− parseSumFromString opts key
1040+parseAllNullarySum :: (SumFromString f, ConstructorNames f)
1041+ => TypeName -> Options -> Value -> Parser (f a)
1042+parseAllNullarySum tname opts =
1043+ withText tname $ \tag ->
1044+ maybe (badTag tag) return $
1045+ parseSumFromString modifier tag
1046+ where
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
1051+
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.
1055+failWithCTags
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
1060+ where
1061+ cnames = unTagged2 (constructorTags modifier :: Tagged2 f [t])
7721062
7731063class SumFromString f where
774− parseSumFromString :: Options -> Text -> Maybe (f a)
1064+ parseSumFromString :: (String -> String) -> Text -> Maybe (f a)
7751065
7761066instance (SumFromString a, SumFromString b) => SumFromString (a :+: b) where
7771067 parseSumFromString opts key = (L1 <$> parseSumFromString opts key) <|>
7781068 (R1 <$> parseSumFromString opts key)
7791069
7801070instance (Constructor c) => SumFromString (C1 c U1) where
781− parseSumFromString opts key | key == name = Just $ M1 U1
782− | otherwise = Nothing
783− where
784− name = pack $ constructorTagModifier opts $
785− conName (undefined :: t c U1 p)
1071+ parseSumFromString modifier key
1072+ | key == name = Just $ M1 U1
1073+ | otherwise = Nothing
1074+ where
1075+ name = pack $ modifier $ conName (undefined :: M1 _i c _f _p)
7861076
787−--------------------------------------------------------------------------------
1077+-- For genericFromJSONKey
1078+instance SumFromString a => SumFromString (D1 d a) where
1079+ parseSumFromString modifier key = M1 <$> parseSumFromString modifier key
7881080
789−parseNonAllNullarySum :: ( FromPair arity (a :+: b)
790− , FromTaggedObject arity (a :+: b)
791− , FromUntaggedValue arity (a :+: b)
792− ) => Options -> FromArgs arity c
793− -> Value -> Parser ((a :+: b) c)
794−parseNonAllNullarySum opts fargs =
1081+-- | List of all constructor tags.
1082+constructorTags :: ConstructorNames a => (String -> t) -> Tagged2 a [t]
1083+constructorTags modifier =
1084+ fmap DList.toList (constructorNames' modifier)
1085+
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)
1090+
1091+instance (ConstructorNames a, ConstructorNames b) => ConstructorNames (a :+: b) where
1092+ constructorNames' = liftA2 append constructorNames' constructorNames'
1093+ where
1094+ append
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)
1099+
1100+instance Constructor c => ConstructorNames (C1 c a) where
1101+ constructorNames' f = Tagged2 (pure (f cname))
1102+ where
1103+ cname = conName (undefined :: M1 _i c _f _p)
1104+
1105+-- For genericFromJSONKey
1106+instance ConstructorNames a => ConstructorNames (D1 d a) where
1107+ constructorNames' = retag . constructorNames'
1108+ where
1109+ retag :: Tagged2 a u -> Tagged2 (D1 d a) u
1110+ retag (Tagged2 x) = Tagged2 x
1111+
1112+--------------------------------------------------------------------------------
1113+parseNonAllNullarySum :: forall f c arity.
1114+ ( FromPair arity f
1115+ , FromTaggedObject arity f
1116+ , FromUntaggedValue arity f
1117+ , ConstructorNames f
1118+ ) => TypeName :* Options :* FromArgs arity c
1119+ -> Value -> Parser (f c)
1120+parseNonAllNullarySum p@(tname :* opts :* _) =
7951121 case sumEncoding opts of
7961122 TaggedObject{..} ->
797− withObject "Object" $ \obj -> do
798− tag <- obj .: pack tagFieldName
799− fromMaybe (notFound tag) $
800− parseFromTaggedObject opts fargs contentsFieldName obj tag
1123+ withObject tname $ \obj -> do
1124+ tag <- contextType tname . contextTag tagKey cnames_ $ obj .: tagKey
1125+ fromMaybe (badTag tag <?> Key tagKey) $
1126+ parseFromTaggedObject (tag :* contentsFieldName :* p) obj
1127+ where
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])
8011133
8021134 ObjectWithSingleField ->
803− withObject "Object" $ \obj ->
804− case H.toList obj of
805− [pair@(tag, _)] -> fromMaybe (notFound tag) $
806− parsePair opts fargs pair
807− _ -> fail "Object doesn't have a single field"
1135+ withObject tname $ \obj -> case H.toList obj of
1136+ [(tag, v)] -> maybe (badTag tag) (<?> Key tag) $
1137+ parsePair (tag :* p) v
1138+ _ -> contextType tname . fail $
1139+ "expected an Object with a single pair, but found " ++
1140+ show (H.size obj) ++ " pairs"
1141+ where
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
8081145
8091146 TwoElemArray ->
810− withArray "Array" $ \arr ->
811− if V.length arr == 2
812− then case V.unsafeIndex arr 0 of
813− String tag -> fromMaybe (notFound tag) $
814− parsePair opts fargs (tag, V.unsafeIndex arr 1)
815− _ -> fail "First element is not a String"
816− else fail "Array doesn't have 2 elements"
1147+ withArray tname $ \arr -> case V.length arr of
1148+ 2 | String tag <- V.unsafeIndex arr 0 ->
1149+ maybe (badTag tag <?> Index 0) (<?> Index 1) $
1150+ parsePair (tag :* p) (V.unsafeIndex arr 1)
1151+ | otherwise ->
1152+ contextType tname $
1153+ fail "tag element is not a String" <?> Index 0
1154+ len -> contextType tname . fail $
1155+ "expected a 2-element Array, but encountered an Array of length " ++
1156+ show len
1157+ where
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
8171161
818− UntaggedValue -> parseUntaggedValue opts fargs
1162+ UntaggedValue -> parseUntaggedValue p
1163+ where
1164+ failWith_ = failWithCTags tname (constructorTagModifier opts)
8191165
8201166--------------------------------------------------------------------------------
8211167
8221168class FromTaggedObject arity f where
823− parseFromTaggedObject :: Options -> FromArgs arity a
824− -> String -> Object
825− -> Text -> Maybe (Parser (f a))
1169+ -- The first two components of the parameter tuple are: the constructor tag
1170+ -- to match against, and the contents field name.
1171+ parseFromTaggedObject
1172+ :: Text :* String :* TypeName :* Options :* FromArgs arity a
1173+ -> Object
1174+ -> Maybe (Parser (f a))
8261175
8271176instance ( FromTaggedObject arity a, FromTaggedObject arity b) =>
8281177 FromTaggedObject arity (a :+: b) where
829− parseFromTaggedObject opts fargs contentsFieldName obj tag =
830− (fmap L1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag) <|>
831− (fmap R1 <$> parseFromTaggedObject opts fargs contentsFieldName obj tag)
1178+ parseFromTaggedObject p obj =
1179+ (fmap L1 <$> parseFromTaggedObject p obj) <|>
1180+ (fmap R1 <$> parseFromTaggedObject p obj)
8321181
833−instance ( FromTaggedObject' arity f
1182+instance ( IsRecord f isRecord
1183+ , FromTaggedObject' arity f isRecord
8341184 , Constructor c
8351185 ) => FromTaggedObject arity (C1 c f) where
836− parseFromTaggedObject opts fargs contentsFieldName obj tag
837− | tag == name = Just $ M1 <$> parseFromTaggedObject'
838− opts fargs contentsFieldName obj
839− | otherwise = Nothing
840− where
841− name = pack $ constructorTagModifier opts $
842− conName (undefined :: t c f p)
1186+ parseFromTaggedObject (tag :* contentsFieldName :* p@(_ :* opts :* _))
1187+ | tag == tag'
1188+ = Just . fmap M1 .
1189+ (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
1190+ parseFromTaggedObject' (contentsFieldName :* cname :* p)
1191+ | otherwise = const Nothing
1192+ where
1193+ tag' = pack $ constructorTagModifier opts cname
1194+ cname = conName (undefined :: M1 _i c _f _p)
8431195
8441196--------------------------------------------------------------------------------
8451197
846−class FromTaggedObject' arity f where
847− parseFromTaggedObject' :: Options -> FromArgs arity a -> String
848− -> Object -> Parser (f a)
849−
850−class FromTaggedObject'' arity f isRecord where
851− parseFromTaggedObject'' :: Options -> FromArgs arity a -> String
852− -> Object -> Tagged isRecord (Parser (f a))
853−
854−instance ( IsRecord f isRecord
855− , FromTaggedObject'' arity f isRecord
856− ) => FromTaggedObject' arity f where
857− parseFromTaggedObject' opts fargs contentsFieldName =
858− (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
859− parseFromTaggedObject'' opts fargs contentsFieldName
860−
861−instance (FromRecord arity f) => FromTaggedObject'' arity f True where
862− parseFromTaggedObject'' opts fargs _ =
863− Tagged . parseRecord opts fargs Nothing
864−
865−instance (GFromJSON arity f) => FromTaggedObject'' arity f False where
866− parseFromTaggedObject'' opts fargs contentsFieldName = Tagged .
867− (gParseJSON opts fargs <=< (.: pack contentsFieldName))
1198+class FromTaggedObject' arity f isRecord where
1199+ -- The first component of the parameter tuple is the contents field name.
1200+ parseFromTaggedObject'
1201+ :: String :* ConName :* TypeName :* Options :* FromArgs arity a
1202+ -> Object -> Tagged isRecord (Parser (f a))
1203+
1204+instance (RecordFromJSON arity f, FieldNames f) => FromTaggedObject' arity f True where
1205+ -- Records are unpacked in the tagged object
1206+ parseFromTaggedObject' (_ :* p) = Tagged . recordParseJSON (True :* p)
1207+
1208+instance (ConsFromJSON arity f) => FromTaggedObject' arity f False where
1209+ -- Nonnullary nonrecords are encoded in the contents field
1210+ parseFromTaggedObject' p obj = Tagged $ do
1211+ contents <- contextCons cname tname (obj .: key)
1212+ consParseJSON p' contents <?> Key key
1213+ where
1214+ key = pack contentsFieldName
1215+ contentsFieldName :* p'@(cname :* tname :* _) = p
8681216
869−instance OVERLAPPING_ FromTaggedObject'' arity U1 False where
870− parseFromTaggedObject'' _ _ _ _ = Tagged (pure U1)
1217+instance OVERLAPPING_ FromTaggedObject' arity U1 False where
1218+ -- Nullary constructors don't need a contents field
1219+ parseFromTaggedObject' _ _ = Tagged (pure U1)
8711220
8721221--------------------------------------------------------------------------------
8731222
1223+-- | Constructors need to be decoded differently depending on whether they're
1224+-- a record or not. This distinction is made by 'ConsParseJSON'.
8741225class ConsFromJSON arity f where
875− consParseJSON :: Options -> FromArgs arity a
876− -> Value -> Parser (f a)
1226+ consParseJSON
1227+ :: ConName :* TypeName :* Options :* FromArgs arity a
1228+ -> Value -> Parser (f a)
8771229
8781230class ConsFromJSON' arity f isRecord where
879− consParseJSON' :: Options -> FromArgs arity a
880− -> Maybe Text -- ^ A dummy label
881− -- (Nothing to use proper label)
882− -> Value -> Tagged isRecord (Parser (f a))
1231+ consParseJSON'
1232+ :: ConName :* TypeName :* Options :* FromArgs arity a
1233+ -> Value -> Tagged isRecord (Parser (f a))
8831234
8841235instance ( IsRecord f isRecord
8851236 , ConsFromJSON' arity f isRecord
8861237 ) => ConsFromJSON arity f where
887− consParseJSON opts fargs v = let
888− (v2,lab) = case (unwrapUnaryRecords opts,isUnary (undefined :: f a)) of
889− -- use a dummy object with a dummy label
890− (True,True) -> (object [(pack "dummy",v)], Just $ pack "dummy")
891− _ ->(v,Nothing)
892− in (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
893− $ consParseJSON' opts fargs lab v2
1238+ consParseJSON p =
1239+ (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
1240+ . consParseJSON' p
8941241
1242+instance OVERLAPPING_
1243+ ( GFromJSON arity a, RecordFromJSON arity (S1 s a)
1244+ ) => ConsFromJSON' arity (S1 s a) True where
1245+ consParseJSON' p@(cname :* tname :* opts :* fargs)
1246+ | unwrapUnaryRecords opts = Tagged . fmap M1 . gParseJSON opts fargs
1247+ | otherwise = Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
8951248
896−instance (FromRecord arity f) => ConsFromJSON' arity f True where
897− consParseJSON' opts fargs mlab = Tagged . withObject "record (:*:)"
898− (parseRecord opts fargs mlab)
1249+instance RecordFromJSON arity f => ConsFromJSON' arity f True where
1250+ consParseJSON' p@(cname :* tname :* _) =
1251+ Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
8991252
900−instance (GFromJSON arity f) => ConsFromJSON' arity f False where
901− consParseJSON' opts fargs _ = Tagged . gParseJSON opts fargs
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
1261+ where
1262+ fail_ a = fail $
1263+ "expected an empty Array, but encountered an Array of length " ++
1264+ show (V.length a)
1265+
1266+instance OVERLAPPING_
1267+ GFromJSON arity f => ConsFromJSON' arity (S1 s f) False where
1268+ consParseJSON' (_ :* _ :* opts :* fargs) =
1269+ Tagged . fmap M1 . gParseJSON opts fargs
1270+
1271+instance (ProductFromJSON arity f, ProductSize f
1272+ ) => ConsFromJSON' arity f False where
1273+ consParseJSON' p = Tagged . productParseJSON0 p
9021274
9031275--------------------------------------------------------------------------------
9041276
905−class FromRecord arity f where
906− parseRecord :: Options -> FromArgs arity a
907− -> Maybe Text -- ^ A dummy label
908− -- (Nothing to use proper label)
909− -> Object -> Parser (f a)
910−
911−instance ( FromRecord arity a
912− , FromRecord arity b
913− ) => FromRecord arity (a :*: b) where
914− parseRecord opts fargs _ obj =
915− (:*:) <$> parseRecord opts fargs Nothing obj
916− <*> parseRecord opts fargs Nothing obj
917−
918−instance ( Selector s
919− , GFromJSON arity a
920− ) => FromRecord arity (S1 s a) where
921− parseRecord opts fargs lab =
922− (<?> Key label) . gParseJSON opts fargs <=< (.: label)
923− where
924− label = fromMaybe defLabel lab
925− defLabel = pack . fieldLabelModifier opts $
926− selName (undefined :: t s a p)
927−
928−instance OVERLAPPING_ (Selector s, FromJSON a) =>
929− FromRecord arity (S1 s (K1 i (Maybe a))) where
930− parseRecord _ _ (Just lab) obj = (M1 . K1) <$> obj .:? lab
931− parseRecord opts _ Nothing obj = (M1 . K1) <$> obj .:? pack label
1277+class FieldNames f where
1278+ fieldNames :: f a -> [Text] -> [Text]
1279+
1280+instance (FieldNames a, FieldNames b) => FieldNames (a :*: b) where
1281+ fieldNames _ =
1282+ fieldNames (undefined :: a x) .
1283+ fieldNames (undefined :: b y)
1284+
1285+instance (Selector s) => FieldNames (S1 s f) where
1286+ fieldNames _ = (pack (selName (undefined :: M1 _i s _f _p)) :)
1287+
1288+class RecordFromJSON arity f where
1289+ recordParseJSON
1290+ :: Bool :* ConName :* TypeName :* Options :* FromArgs arity a
1291+ -> Object -> Parser (f a)
1292+
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
9321298 where
933− label = fieldLabelModifier opts $
934− selName (undefined :: t s (K1 i (Maybe a)) p)
1299+ knownFields :: H.HashMap Text ()
1300+ knownFields = H.fromList $ map (,()) $
1301+ fieldNames (undefined :: f a)
1302+ [pack (tagFieldName (sumEncoding opts)) | fromTaggedSum]
1303+ checkUnknown =
1304+ if not (rejectUnknownFields opts)
1305+ then \_ -> return ()
1306+ else \obj -> case H.keys (H.difference obj knownFields) of
1307+ [] -> return ()
1308+ unknownFields -> contextCons cname tname $
1309+ fail ("unknown fields: " ++ show unknownFields)
1310+
1311+class RecordFromJSON' arity f where
1312+ recordParseJSON'
1313+ :: ConName :* TypeName :* Options :* FromArgs arity a
1314+ -> Object -> Parser (f a)
1315+
1316+instance ( RecordFromJSON' arity a
1317+ , RecordFromJSON' arity b
1318+ ) => RecordFromJSON' arity (a :*: b) where
1319+ recordParseJSON' p obj =
1320+ (:*:) <$> recordParseJSON' p obj
1321+ <*> recordParseJSON' p obj
1322+
1323+instance OVERLAPPABLE_ (Selector s, GFromJSON arity a) =>
1324+ RecordFromJSON' arity (S1 s a) where
1325+ recordParseJSON' (cname :* tname :* opts :* fargs) obj = do
1326+ fv <- contextCons cname tname (obj .: label)
1327+ M1 <$> gParseJSON opts fargs fv <?> Key label
1328+ where
1329+ label = pack $ fieldLabelModifier opts sname
1330+ sname = selName (undefined :: M1 _i s _f _p)
1331+
1332+instance INCOHERENT_ (Selector s, FromJSON a) =>
1333+ RecordFromJSON' arity (S1 s (K1 i (Maybe a))) where
1334+ recordParseJSON' (_ :* _ :* opts :* _) obj = M1 . K1 <$> obj .:? pack label
1335+ where
1336+ label = fieldLabelModifier opts sname
1337+ sname = selName (undefined :: M1 _i s _f _p)
1338+
1339+-- Parse an Option like a Maybe.
1340+instance INCOHERENT_ (Selector s, FromJSON a) =>
1341+ RecordFromJSON' arity (S1 s (K1 i (Semigroup.Option a))) where
1342+ recordParseJSON' p obj = wrap <$> recordParseJSON' p obj
1343+ where
1344+ wrap :: S1 s (K1 i (Maybe a)) p -> S1 s (K1 i (Semigroup.Option a)) p
1345+ wrap (M1 (K1 a)) = M1 (K1 (Semigroup.Option a))
9351346
9361347--------------------------------------------------------------------------------
9371348
938−class FromProduct arity f where
939− parseProduct :: Options -> FromArgs arity a
1349+productParseJSON0
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)
1360+ productSize in
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
1366+
1367+--
1368+
1369+class ProductFromJSON arity f where
1370+ productParseJSON :: ConName :* TypeName :* Options :* FromArgs arity a
9401371 -> Array -> Int -> Int
9411372 -> Parser (f a)
9421373
943−instance ( FromProduct arity a
944− , FromProduct arity b
945− ) => FromProduct arity (a :*: b) where
946− parseProduct opts fargs arr ix len =
947− (:*:) <$> parseProduct opts fargs arr ix lenL
948− <*> parseProduct opts fargs arr ixR lenR
1374+instance ( ProductFromJSON arity a
1375+ , ProductFromJSON arity b
1376+ ) => ProductFromJSON arity (a :*: b) where
1377+ productParseJSON p arr ix len =
1378+ (:*:) <$> productParseJSON p arr ix lenL
1379+ <*> productParseJSON p arr ixR lenR
9491380 where
9501381 lenL = len `unsafeShiftR` 1
9511382 ixR = ix + lenL
9521383 lenR = len - lenL
9531384
954−instance (GFromJSON arity a) => FromProduct arity (S1 s a) where
955− parseProduct opts fargs arr ix _ =
956− gParseJSON opts fargs $ V.unsafeIndex arr ix
1385+instance (GFromJSON arity a) => ProductFromJSON arity (S1 s a) where
1386+ productParseJSON (_ :* _ :* opts :* fargs) arr ix _ =
1387+ M1 <$> gParseJSON opts fargs (V.unsafeIndex arr ix) <?> Index ix
9571388
9581389--------------------------------------------------------------------------------
9591390
9601391class FromPair arity f where
961− parsePair :: Options -> FromArgs arity a
962− -> Pair -> Maybe (Parser (f a))
1392+ -- The first component of the parameter tuple is the tag to match.
1393+ parsePair :: Text :* TypeName :* Options :* FromArgs arity a
1394+ -> Value
1395+ -> Maybe (Parser (f a))
9631396
9641397instance ( FromPair arity a
9651398 , FromPair arity b
9661399 ) => FromPair arity (a :+: b) where
967− parsePair opts fargs pair = (fmap L1 <$> parsePair opts fargs pair) <|>
968− (fmap R1 <$> parsePair opts fargs pair)
1400+ parsePair p pair =
1401+ (fmap L1 <$> parsePair p pair) <|>
1402+ (fmap R1 <$> parsePair p pair)
9691403
9701404instance ( Constructor c
971− , GFromJSON arity a
9721405 , ConsFromJSON arity a
9731406 ) => FromPair arity (C1 c a) where
974− parsePair opts fargs (tag, value)
975− | tag == tag' = Just $ gParseJSON opts fargs value
1407+ parsePair (tag :* p@(_ :* opts :* _)) v
1408+ | tag == tag' = Just $ M1 <$> consParseJSON (cname :* p) v
9761409 | otherwise = Nothing
977− where
978− tag' = pack $ constructorTagModifier opts $
979− conName (undefined :: t c a p)
1410+ where
1411+ tag' = pack $ constructorTagModifier opts cname
1412+ cname = conName (undefined :: M1 _i c _a _p)
9801413
9811414--------------------------------------------------------------------------------
9821415
9831416class FromUntaggedValue arity f where
984− parseUntaggedValue :: Options -> FromArgs arity a
985− -> Value -> Parser (f a)
1417+ parseUntaggedValue :: TypeName :* Options :* FromArgs arity a
1418+ -> Value
1419+ -> Parser (f a)
9861420
9871421instance
9881422 ( FromUntaggedValue arity a
9891423 , FromUntaggedValue arity b
9901424 ) => FromUntaggedValue arity (a :+: b)
9911425 where
992− parseUntaggedValue opts fargs value =
993− L1 <$> parseUntaggedValue opts fargs value <|>
994− R1 <$> parseUntaggedValue opts fargs value
1426+ parseUntaggedValue p value =
1427+ L1 <$> parseUntaggedValue p value <|>
1428+ R1 <$> parseUntaggedValue p value
9951429
9961430instance OVERLAPPABLE_
997− ( GFromJSON arity a
998− , ConsFromJSON arity a
1431+ ( ConsFromJSON arity a
1432+ , Constructor c
9991433 ) => FromUntaggedValue arity (C1 c a)
10001434 where
1001− parseUntaggedValue = gParseJSON
1435+ parseUntaggedValue p = fmap M1 . consParseJSON (cname :* p)
1436+ where
1437+ cname = conName (undefined :: M1 _i c _f _p)
10021438
10031439instance OVERLAPPING_
10041440 ( Constructor c )
10051441 => FromUntaggedValue arity (C1 c U1)
10061442 where
1007− parseUntaggedValue opts _ (String s)
1008− | s == pack (constructorTagModifier opts (conName (undefined :: t c U1 p))) =
1009− pure $ M1 U1
1010− | otherwise =
1011− fail $ "Invalid tag: " ++ unpack s
1012− parseUntaggedValue _ _ v = typeMismatch (conName (undefined :: t c U1 p)) v
1013−
1014−
1015−--------------------------------------------------------------------------------
1016−
1017−notFound :: Text -> Parser a
1018−notFound key = fail $ "The key \"" ++ unpack key ++ "\" was not found"
1019−{-# INLINE notFound #-}
1443+ parseUntaggedValue (tname :* opts :* _) v =
1444+ contextCons cname tname $ case v of
1445+ String tag
1446+ | tag == tag' -> pure $ M1 U1
1447+ | otherwise -> fail_ tag
1448+ _ -> typeMismatch "String" v
1449+ where
1450+ tag' = pack $ constructorTagModifier opts cname
1451+ cname = conName (undefined :: M1 _i c _f _p)
1452+ fail_ tag = fail $
1453+ "expected tag " ++ show tag' ++ ", but found tag " ++ show tag
10201454
10211455-------------------------------------------------------------------------------
10221456-- Instances
@@ -1074,17 +1508,20 @@ instance (FromJSON a, FromJSON b) => FromJSON (Either a b) where
10741508 parseJSON = parseJSON2
10751509 {-# INLINE parseJSON #-}
10761510
1077−
1511+instance FromJSON Void where
1512+ parseJSON _ = fail "Cannot parse Void"
1513+ {-# INLINE parseJSON #-}
10781514
10791515instance FromJSON Bool where
1080− parseJSON = withBool "Bool" pure
1516+ parseJSON (Bool b) = pure b
1517+ parseJSON v = typeMismatch "Bool" v
10811518 {-# INLINE parseJSON #-}
10821519
10831520instance FromJSONKey Bool where
10841521 fromJSONKey = FromJSONKeyTextParser $ \t -> case t of
10851522 "true" -> pure True
10861523 "false" -> pure False
1087− _ -> fail $ "Cannot parse key into Bool: " ++ T.unpack t
1524+ _ -> fail $ "cannot parse key " ++ show t ++ " into Bool"
10881525
10891526instance FromJSON Ordering where
10901527 parseJSON = withText "Ordering" $ \s ->
@@ -1092,25 +1529,30 @@ instance FromJSON Ordering where
10921529 "LT" -> return LT
10931530 "EQ" -> return EQ
10941531 "GT" -> return GT
1095− _ -> fail "Parsing Ordering value failed: expected \"LT\", \"EQ\", or \"GT\""
1532+ _ -> fail $ "parsing Ordering failed, unexpected " ++ show s ++
1533+ " (expected \"LT\", \"EQ\", or \"GT\")"
10961534
10971535instance FromJSON () where
10981536 parseJSON = withArray "()" $ \v ->
10991537 if V.null v
11001538 then pure ()
1101− else fail "Expected an empty array"
1539+ else prependContext "()" $ fail "expected an empty array"
11021540 {-# INLINE parseJSON #-}
11031541
11041542instance FromJSON Char where
1105− parseJSON = withText "Char" $ \t ->
1106− if T.compareLength t 1 == EQ
1107− then pure $ T.head t
1108− else fail "Expected a string of length 1"
1543+ parseJSON = withText "Char" parseChar
11091544 {-# INLINE parseJSON #-}
11101545
1111− parseJSONList = withText "String" $ pure . T.unpack
1546+ parseJSONList (String s) = pure (T.unpack s)
1547+ parseJSONList v = typeMismatch "String" v
11121548 {-# INLINE parseJSONList #-}
11131549
1550+parseChar :: Text -> Parser Char
1551+parseChar t =
1552+ if T.compareLength t 1 == EQ
1553+ then pure $ T.head t
1554+ else prependContext "Char" $ fail "expected a string of length 1"
1555+
11141556instance FromJSON Double where
11151557 parseJSON = parseRealFloat "Double"
11161558 {-# INLINE parseJSON #-}
@@ -1122,12 +1564,6 @@ instance FromJSONKey Double where
11221564 "-Infinity" -> pure (negate 1/0)
11231565 _ -> Scientific.toRealFloat <$> parseScientificText t
11241566
1125−instance FromJSON Number where
1126− parseJSON (Number s) = pure $ scientificToNumber s
1127− parseJSON Null = pure (D (0/0))
1128− parseJSON v = typeMismatch "Number" v
1129− {-# INLINE parseJSON #-}
1130−
11311567instance FromJSON Float where
11321568 parseJSON = parseRealFloat "Float"
11331569 {-# INLINE parseJSON #-}
@@ -1140,112 +1576,133 @@ instance FromJSONKey Float where
11401576 _ -> Scientific.toRealFloat <$> parseScientificText t
11411577
11421578instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
1143− parseJSON = withObject "Rational" $ \obj ->
1144− (%) <$> obj .: "numerator"
1145− <*> obj .: "denominator"
1146− {-# INLINE parseJSON #-}
1147−
1148−-- | /WARNING:/ Only parse fixed-precision numbers from trusted input
1149−-- since an attacker could easily fill up the memory of the target
1150−-- system by specifying a scientific number with a big exponent like
1151−-- @1e1000000000@.
1579+ parseJSON (Number x)
1580+ | exp10 <= 1024
1581+ , exp10 >= -1024 = return $! realToFrac x
1582+ | otherwise = prependContext "Ratio" $ fail msg
1583+ where
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
1588+ where
1589+ objParser = withObject "Rational" $ \obj -> do
1590+ numerator <- obj .: "numerator"
1591+ denominator <- obj .: "denominator"
1592+ if denominator == 0
1593+ then fail "Ratio denominator was 0"
1594+ else pure $ numerator % denominator
1595+ {-# INLINE parseJSON #-}
1596+
1597+-- | This instance includes a bounds check to prevent maliciously
1598+-- large inputs to fill up the memory of the target system. You can
1599+-- newtype 'Scientific' and provide your own instance using
1600+-- 'withScientific' if you want to allow larger inputs.
11521601instance HasResolution a => FromJSON (Fixed a) where
1153− parseJSON = withScientific "Fixed" $ pure . realToFrac
1602+ parseJSON = prependContext "Fixed" . withBoundedScientific' (pure . realToFrac)
11541603 {-# INLINE parseJSON #-}
11551604
11561605instance FromJSON Int where
1157− parseJSON = parseIntegral "Int"
1606+ parseJSON = parseBoundedIntegral "Int"
11581607 {-# INLINE parseJSON #-}
11591608
11601609instance FromJSONKey Int where
1161− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1610+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int"
11621611
1163−-- | /WARNING:/ Only parse Integers from trusted input since an
1164−-- attacker could easily fill up the memory of the target system by
1165−-- specifying a scientific number with a big exponent like
1166−-- @1e1000000000@.
1612+-- | This instance includes a bounds check to prevent maliciously
1613+-- large inputs to fill up the memory of the target system. You can
1614+-- newtype 'Scientific' and provide your own instance using
1615+-- 'withScientific' if you want to allow larger inputs.
11671616instance FromJSON Integer where
1168− parseJSON = withScientific "Integral" $ pure . truncate
1617+ parseJSON = parseIntegral "Integer"
11691618 {-# INLINE parseJSON #-}
11701619
11711620instance FromJSONKey Integer where
1172− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1621+ fromJSONKey = FromJSONKeyTextParser $ parseIntegralText "Integer"
11731622
11741623instance FromJSON Natural where
1175− parseJSON = withScientific "Natural" $ \s ->
1176− if Scientific.coefficient s < 0
1177− then fail $ "Expected a Natural number but got the negative number: " <> show s
1178− else pure $ truncate s
1624+ parseJSON value = do
1625+ integer <- parseIntegral "Natural" value
1626+ parseNatural integer
11791627
11801628instance FromJSONKey Natural where
1181− fromJSONKey = FromJSONKeyTextParser $ \t -> parseScientificText t >>= \s ->
1182− if Scientific.coefficient s < 0
1183− then fail $ "Expected a Natural number but got the negative number: " <> show s
1184− else pure $ truncate s
1629+ fromJSONKey = FromJSONKeyTextParser $ \text -> do
1630+ integer <- parseIntegralText "Natural" text
1631+ parseNatural integer
1632+
1633+parseNatural :: Integer -> Parser Natural
1634+parseNatural integer =
1635+ if integer < 0 then
1636+ fail $ "parsing Natural failed, unexpected negative number " <> show integer
1637+ else
1638+ pure $ fromIntegral integer
11851639
11861640instance FromJSON Int8 where
1187− parseJSON = parseIntegral "Int8"
1641+ parseJSON = parseBoundedIntegral "Int8"
11881642 {-# INLINE parseJSON #-}
11891643
11901644instance FromJSONKey Int8 where
1191− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1645+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int8"
11921646
11931647instance FromJSON Int16 where
1194− parseJSON = parseIntegral "Int16"
1648+ parseJSON = parseBoundedIntegral "Int16"
11951649 {-# INLINE parseJSON #-}
11961650
11971651instance FromJSONKey Int16 where
1198− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1652+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int16"
11991653
12001654instance FromJSON Int32 where
1201− parseJSON = parseIntegral "Int32"
1655+ parseJSON = parseBoundedIntegral "Int32"
12021656 {-# INLINE parseJSON #-}
12031657
12041658instance FromJSONKey Int32 where
1205− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1659+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int32"
12061660
12071661instance FromJSON Int64 where
1208− parseJSON = parseIntegral "Int64"
1662+ parseJSON = parseBoundedIntegral "Int64"
12091663 {-# INLINE parseJSON #-}
12101664
12111665instance FromJSONKey Int64 where
1212− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1666+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int64"
12131667
12141668instance FromJSON Word where
1215− parseJSON = parseIntegral "Word"
1669+ parseJSON = parseBoundedIntegral "Word"
12161670 {-# INLINE parseJSON #-}
12171671
12181672instance FromJSONKey Word where
1219− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1673+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word"
12201674
12211675instance FromJSON Word8 where
1222− parseJSON = parseIntegral "Word8"
1676+ parseJSON = parseBoundedIntegral "Word8"
12231677 {-# INLINE parseJSON #-}
12241678
12251679instance FromJSONKey Word8 where
1226− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1680+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word8"
12271681
12281682instance FromJSON Word16 where
1229− parseJSON = parseIntegral "Word16"
1683+ parseJSON = parseBoundedIntegral "Word16"
12301684 {-# INLINE parseJSON #-}
12311685
12321686instance FromJSONKey Word16 where
1233− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1687+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word16"
12341688
12351689instance FromJSON Word32 where
1236− parseJSON = parseIntegral "Word32"
1690+ parseJSON = parseBoundedIntegral "Word32"
12371691 {-# INLINE parseJSON #-}
12381692
12391693instance FromJSONKey Word32 where
1240− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1694+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word32"
12411695
12421696instance FromJSON Word64 where
1243− parseJSON = parseIntegral "Word64"
1697+ parseJSON = parseBoundedIntegral "Word64"
12441698 {-# INLINE parseJSON #-}
12451699
12461700instance FromJSONKey Word64 where
1247− fromJSONKey = FromJSONKeyTextParser parseIntegralText
1701+ fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word64"
12481702
1703+instance FromJSON CTime where
1704+ parseJSON = fmap CTime . parseJSON
1705+ {-# INLINE parseJSON #-}
12491706
12501707instance FromJSON Text where
12511708 parseJSON = withText "Text" pure
@@ -1275,17 +1732,17 @@ parseVersionText = go . readP_to_S parseVersion . unpack
12751732 where
12761733 go [(v,[])] = return v
12771734 go (_ : xs) = go xs
1278− go _ = fail "could not parse Version"
1735+ go _ = fail "parsing Version failed"
12791736
12801737-------------------------------------------------------------------------------
12811738-- semigroups NonEmpty
12821739-------------------------------------------------------------------------------
12831740
12841741instance FromJSON1 NonEmpty where
1285− liftParseJSON p _ = withArray "NonEmpty a" $
1742+ liftParseJSON p _ = withArray "NonEmpty" $
12861743 (>>= ne) . Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
12871744 where
1288− ne [] = fail "Expected a NonEmpty but got an empty list"
1745+ ne [] = fail "parsing NonEmpty failed, unexpected empty list"
12891746 ne (x:xs) = pure (x :| xs)
12901747 {-# INLINE liftParseJSON #-}
12911748
@@ -1306,7 +1763,7 @@ instance FromJSON Scientific where
13061763-------------------------------------------------------------------------------
13071764
13081765instance FromJSON1 DList.DList where
1309− liftParseJSON p _ = withArray "DList a" $
1766+ liftParseJSON p _ = withArray "DList" $
13101767 fmap DList.fromList .
13111768 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
13121769 {-# INLINE liftParseJSON #-}
@@ -1333,7 +1790,7 @@ instance (FromJSON a) => FromJSON (Identity a) where
13331790 parseJSONList = liftParseJSONList parseJSON parseJSONList
13341791 {-# INLINE parseJSONList #-}
13351792
1336−instance (FromJSONKey a, FromJSON a) => FromJSONKey (Identity a) where
1793+instance (FromJSONKey a) => FromJSONKey (Identity a) where
13371794 fromJSONKey = coerceFromJSONKeyFunction (fromJSONKey :: FromJSONKeyFunction a)
13381795 fromJSONKeyList = coerceFromJSONKeyFunction (fromJSONKeyList :: FromJSONKeyFunction [a])
13391796
@@ -1383,7 +1840,7 @@ instance (FromJSON1 f, FromJSON1 g) => FromJSON1 (Sum f g) where
13831840 inr = "InR"
13841841
13851842 liftParseJSON _ _ _ = fail $
1386− "expected an object with a single property " ++
1843+ "parsing Sum failed, expected an object with a single property " ++
13871844 "where the property key should be either " ++
13881845 "\"InL\" or \"InR\""
13891846 {-# INLINE liftParseJSON #-}
@@ -1397,7 +1854,7 @@ instance (FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum f g a) where
13971854-------------------------------------------------------------------------------
13981855
13991856instance FromJSON1 Seq.Seq where
1400− liftParseJSON p _ = withArray "Seq a" $
1857+ liftParseJSON p _ = withArray "Seq" $
14011858 fmap Seq.fromList .
14021859 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
14031860 {-# INLINE liftParseJSON #-}
@@ -1431,15 +1888,15 @@ instance FromJSON a => FromJSON (IntMap.IntMap a) where
14311888
14321889instance (FromJSONKey k, Ord k) => FromJSON1 (M.Map k) where
14331890 liftParseJSON p _ = case fromJSONKey of
1434− FromJSONKeyCoerce _-> withObject "Map k v" $
1891+ FromJSONKeyCoerce _ -> withObject "Map" $
14351892 fmap (H.foldrWithKey (M.insert . unsafeCoerce) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1436− FromJSONKeyText f -> withObject "Map k v" $
1893+ FromJSONKeyText f -> withObject "Map" $
14371894 fmap (H.foldrWithKey (M.insert . f) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1438− FromJSONKeyTextParser f -> withObject "Map k v" $
1895+ FromJSONKeyTextParser f -> withObject "Map" $
14391896 H.foldrWithKey (\k v m -> M.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure M.empty)
1440− FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1441− M.fromList <$> (Tr.sequence .
1442− zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr)
1897+ FromJSONKeyValue f -> withArray "Map" $ \arr ->
1898+ fmap M.fromList . Tr.sequence .
1899+ zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
14431900 {-# INLINE liftParseJSON #-}
14441901
14451902instance (FromJSONKey k, Ord k, FromJSON v) => FromJSON (M.Map k v) where
@@ -1459,12 +1916,24 @@ instance (FromJSON v) => FromJSON (Tree.Tree v) where
14591916 parseJSON = parseJSON1
14601917 {-# INLINE parseJSON #-}
14611918
1919+-------------------------------------------------------------------------------
1920+-- uuid
1921+-------------------------------------------------------------------------------
1922+
1923+instance FromJSON UUID.UUID where
1924+ parseJSON = withText "UUID" $
1925+ maybe (fail "invalid UUID") pure . UUID.fromText
1926+
1927+instance FromJSONKey UUID.UUID where
1928+ fromJSONKey = FromJSONKeyTextParser $
1929+ maybe (fail "invalid UUID") pure . UUID.fromText
1930+
14621931-------------------------------------------------------------------------------
14631932-- vector
14641933-------------------------------------------------------------------------------
14651934
14661935instance FromJSON1 Vector where
1467− liftParseJSON p _ = withArray "Vector a" $
1936+ liftParseJSON p _ = withArray "Vector" $
14681937 V.mapM (uncurry $ parseIndexedJSON p) . V.indexed
14691938 {-# INLINE liftParseJSON #-}
14701939
@@ -1478,14 +1947,14 @@ vectorParseJSON s = withArray s $ fmap V.convert . V.mapM (uncurry $ parseIndexe
14781947{-# INLINE vectorParseJSON #-}
14791948
14801949instance (Storable a, FromJSON a) => FromJSON (VS.Vector a) where
1481− parseJSON = vectorParseJSON "Data.Vector.Storable.Vector a"
1950+ parseJSON = vectorParseJSON "Data.Vector.Storable.Vector"
14821951
14831952instance (VP.Prim a, FromJSON a) => FromJSON (VP.Vector a) where
1484− parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector a"
1953+ parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector"
14851954 {-# INLINE parseJSON #-}
14861955
14871956instance (VG.Vector VU.Vector a, FromJSON a) => FromJSON (VU.Vector a) where
1488− parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector a"
1957+ parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector"
14891958 {-# INLINE parseJSON #-}
14901959
14911960-------------------------------------------------------------------------------
@@ -1499,15 +1968,15 @@ instance (Eq a, Hashable a, FromJSON a) => FromJSON (HashSet.HashSet a) where
14991968
15001969instance (FromJSONKey k, Eq k, Hashable k) => FromJSON1 (H.HashMap k) where
15011970 liftParseJSON p _ = case fromJSONKey of
1502− FromJSONKeyCoerce _ -> withObject "HashMap ~Text v" $
1971+ FromJSONKeyCoerce _ -> withObject "HashMap ~Text" $
15031972 uc . H.traverseWithKey (\k v -> p v <?> Key k)
1504− FromJSONKeyText f -> withObject "HashMap k v" $
1973+ FromJSONKeyText f -> withObject "HashMap" $
15051974 fmap (mapKey f) . H.traverseWithKey (\k v -> p v <?> Key k)
1506− FromJSONKeyTextParser f -> withObject "HashMap k v" $
1975+ FromJSONKeyTextParser f -> withObject "HashMap" $
15071976 H.foldrWithKey (\k v m -> H.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure H.empty)
1508− FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1509− H.fromList <$> (Tr.sequence .
1510− zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr)
1977+ FromJSONKeyValue f -> withArray "Map" $ \arr ->
1978+ fmap H.fromList . Tr.sequence .
1979+ zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
15111980 where
15121981 uc :: Parser (H.HashMap Text v) -> Parser (H.HashMap k v)
15131982 uc = unsafeCoerce
@@ -1528,11 +1997,33 @@ instance FromJSON DotNetTime where
15281997 parseJSON = withText "DotNetTime" $ \t ->
15291998 let (s,m) = T.splitAt (T.length t - 5) t
15301999 t' = T.concat [s,".",m]
1531− in case parseTime defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
2000+ in case parseTimeM True defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
15322001 Just d -> pure (DotNetTime d)
15332002 _ -> fail "could not parse .NET time"
15342003 {-# INLINE parseJSON #-}
15352004
2005+-------------------------------------------------------------------------------
2006+-- primitive
2007+-------------------------------------------------------------------------------
2008+
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
2013+
2014+instance FromJSON a => FromJSON (PM.SmallArray a) where
2015+ parseJSON = fmap Exts.fromList . parseJSON
2016+
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
2020+
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
2024+#endif
2025+#endif
2026+
15362027-------------------------------------------------------------------------------
15372028-- time
15382029-------------------------------------------------------------------------------
@@ -1558,6 +2049,17 @@ instance FromJSONKey LocalTime where
15582049 fromJSONKey = FromJSONKeyTextParser (Time.run Time.localTime)
15592050
15602051
2052+-- | Supported string formats:
2053+--
2054+-- @YYYY-MM-DD HH:MM Z@
2055+-- @YYYY-MM-DD HH:MM:SS Z@
2056+-- @YYYY-MM-DD HH:MM:SS.SSS Z@
2057+--
2058+-- The first space may instead be a @T@, and the second space is
2059+-- optional. The @Z@ represents UTC. The @Z@ may be replaced with a
2060+-- time zone offset of the form @+0000@ or @-08:00@, where the first
2061+-- two digits are hours, the @:@ is optional and the second two digits
2062+-- (also optional) are minutes.
15612063instance FromJSON ZonedTime where
15622064 parseJSON = withText "ZonedTime" (Time.run Time.zonedTime)
15632065
@@ -1572,41 +2074,168 @@ instance FromJSONKey UTCTime where
15722074 fromJSONKey = FromJSONKeyTextParser (Time.run Time.utcTime)
15732075
15742076
1575−-- | /WARNING:/ Only parse lengths of time from trusted input
1576−-- since an attacker could easily fill up the memory of the target
1577−-- system by specifying a scientific number with a big exponent like
1578−-- @1e1000000000@.
2077+-- | This instance includes a bounds check to prevent maliciously
2078+-- large inputs to fill up the memory of the target system. You can
2079+-- newtype 'Scientific' and provide your own instance using
2080+-- 'withScientific' if you want to allow larger inputs.
15792081instance FromJSON NominalDiffTime where
1580− parseJSON = withScientific "NominalDiffTime" $ pure . realToFrac
2082+ parseJSON = withBoundedScientific "NominalDiffTime" $ pure . realToFrac
2083+ {-# INLINE parseJSON #-}
2084+
2085+
2086+-- | This instance includes a bounds check to prevent maliciously
2087+-- large inputs to fill up the memory of the target system. You can
2088+-- newtype 'Scientific' and provide your own instance using
2089+-- 'withScientific' if you want to allow larger inputs.
2090+instance FromJSON DiffTime where
2091+ parseJSON = withBoundedScientific "DiffTime" $ pure . realToFrac
15812092 {-# INLINE parseJSON #-}
15822093
2094+instance FromJSON SystemTime where
2095+ parseJSON v = prependContext "SystemTime" $ do
2096+ n <- parseJSON v
2097+ let n' = floor (n * fromInteger (resolution n) :: Nano)
2098+ let (secs, nano) = n' `divMod` resolution n
2099+ return (MkSystemTime (fromInteger secs) (fromInteger nano))
2100+
2101+instance FromJSON CalendarDiffTime where
2102+ parseJSON = withObject "CalendarDiffTime" $ \obj -> CalendarDiffTime
2103+ <$> obj .: "months"
2104+ <*> obj .: "time"
2105+
2106+instance FromJSON CalendarDiffDays where
2107+ parseJSON = withObject "CalendarDiffDays" $ \obj -> CalendarDiffDays
2108+ <$> obj .: "months"
2109+ <*> obj .: "days"
2110+
2111+instance FromJSON DayOfWeek where
2112+ parseJSON = withText "DaysOfWeek" parseDayOfWeek
2113+
2114+parseDayOfWeek :: T.Text -> Parser DayOfWeek
2115+parseDayOfWeek t = case T.toLower t of
2116+ "monday" -> return Monday
2117+ "tuesday" -> return Tuesday
2118+ "wednesday" -> return Wednesday
2119+ "thursday" -> return Thursday
2120+ "friday" -> return Friday
2121+ "saturday" -> return Saturday
2122+ "sunday" -> return Sunday
2123+ _ -> fail "Invalid week day"
2124+
2125+instance FromJSONKey DayOfWeek where
2126+ fromJSONKey = FromJSONKeyTextParser parseDayOfWeek
2127+
15832128-------------------------------------------------------------------------------
15842129-- base Monoid/Semigroup
15852130-------------------------------------------------------------------------------
15862131
1587−instance FromJSON1 Dual where
1588− liftParseJSON p _ = fmap Dual . p
2132+instance FromJSON1 Monoid.Dual where
2133+ liftParseJSON p _ = fmap Monoid.Dual . p
2134+ {-# INLINE liftParseJSON #-}
2135+
2136+instance FromJSON a => FromJSON (Monoid.Dual a) where
2137+ parseJSON = parseJSON1
2138+ {-# INLINE parseJSON #-}
2139+
2140+
2141+instance FromJSON1 Monoid.First where
2142+ liftParseJSON p p' = fmap Monoid.First . liftParseJSON p p'
2143+ {-# INLINE liftParseJSON #-}
2144+
2145+instance FromJSON a => FromJSON (Monoid.First a) where
2146+ parseJSON = parseJSON1
2147+ {-# INLINE parseJSON #-}
2148+
2149+
2150+instance FromJSON1 Monoid.Last where
2151+ liftParseJSON p p' = fmap Monoid.Last . liftParseJSON p p'
2152+ {-# INLINE liftParseJSON #-}
2153+
2154+instance FromJSON a => FromJSON (Monoid.Last a) where
2155+ parseJSON = parseJSON1
2156+ {-# INLINE parseJSON #-}
2157+
2158+
2159+instance FromJSON1 Semigroup.Min where
2160+ liftParseJSON p _ a = Semigroup.Min <$> p a
15892161 {-# INLINE liftParseJSON #-}
15902162
1591−instance FromJSON a => FromJSON (Dual a) where
2163+ liftParseJSONList _ p a = fmap Semigroup.Min <$> p a
2164+ {-# INLINE liftParseJSONList #-}
2165+
2166+instance (FromJSON a) => FromJSON (Semigroup.Min a) where
15922167 parseJSON = parseJSON1
15932168 {-# INLINE parseJSON #-}
15942169
2170+ parseJSONList = liftParseJSONList parseJSON parseJSONList
2171+ {-# INLINE parseJSONList #-}
15952172
1596−instance FromJSON1 First where
1597− liftParseJSON p p' = fmap First . liftParseJSON p p'
2173+
2174+instance FromJSON1 Semigroup.Max where
2175+ liftParseJSON p _ a = Semigroup.Max <$> p a
15982176 {-# INLINE liftParseJSON #-}
15992177
1600−instance FromJSON a => FromJSON (First a) where
2178+ liftParseJSONList _ p a = fmap Semigroup.Max <$> p a
2179+ {-# INLINE liftParseJSONList #-}
2180+
2181+instance (FromJSON a) => FromJSON (Semigroup.Max a) where
16012182 parseJSON = parseJSON1
16022183 {-# INLINE parseJSON #-}
16032184
2185+ parseJSONList = liftParseJSONList parseJSON parseJSONList
2186+ {-# INLINE parseJSONList #-}
2187+
16042188
1605−instance FromJSON1 Last where
1606− liftParseJSON p p' = fmap Last . liftParseJSON p p'
2189+instance FromJSON1 Semigroup.First where
2190+ liftParseJSON p _ a = Semigroup.First <$> p a
16072191 {-# INLINE liftParseJSON #-}
16082192
1609−instance FromJSON a => FromJSON (Last a) where
2193+ liftParseJSONList _ p a = fmap Semigroup.First <$> p a
2194+ {-# INLINE liftParseJSONList #-}
2195+
2196+instance (FromJSON a) => FromJSON (Semigroup.First a) where
2197+ parseJSON = parseJSON1
2198+ {-# INLINE parseJSON #-}
2199+
2200+ parseJSONList = liftParseJSONList parseJSON parseJSONList
2201+ {-# INLINE parseJSONList #-}
2202+
2203+
2204+instance FromJSON1 Semigroup.Last where
2205+ liftParseJSON p _ a = Semigroup.Last <$> p a
2206+ {-# INLINE liftParseJSON #-}
2207+
2208+ liftParseJSONList _ p a = fmap Semigroup.Last <$> p a
2209+ {-# INLINE liftParseJSONList #-}
2210+
2211+instance (FromJSON a) => FromJSON (Semigroup.Last a) where
2212+ parseJSON = parseJSON1
2213+ {-# INLINE parseJSON #-}
2214+
2215+ parseJSONList = liftParseJSONList parseJSON parseJSONList
2216+ {-# INLINE parseJSONList #-}
2217+
2218+
2219+instance FromJSON1 Semigroup.WrappedMonoid where
2220+ liftParseJSON p _ a = Semigroup.WrapMonoid <$> p a
2221+ {-# INLINE liftParseJSON #-}
2222+
2223+ liftParseJSONList _ p a = fmap Semigroup.WrapMonoid <$> p a
2224+ {-# INLINE liftParseJSONList #-}
2225+
2226+instance (FromJSON a) => FromJSON (Semigroup.WrappedMonoid a) where
2227+ parseJSON = parseJSON1
2228+ {-# INLINE parseJSON #-}
2229+
2230+ parseJSONList = liftParseJSONList parseJSON parseJSONList
2231+ {-# INLINE parseJSONList #-}
2232+
2233+
2234+instance FromJSON1 Semigroup.Option where
2235+ liftParseJSON p p' = fmap Semigroup.Option . liftParseJSON p p'
2236+ {-# INLINE liftParseJSON #-}
2237+
2238+instance FromJSON a => FromJSON (Semigroup.Option a) where
16102239 parseJSON = parseJSON1
16112240 {-# INLINE parseJSON #-}
16122241
@@ -1614,11 +2243,21 @@ instance FromJSON a => FromJSON (Last a) where
16142243-- tagged
16152244-------------------------------------------------------------------------------
16162245
2246+instance FromJSON1 Proxy where
2247+ {-# INLINE liftParseJSON #-}
2248+ liftParseJSON _ _ = fromNull "Proxy" Proxy
2249+
16172250instance FromJSON (Proxy a) where
16182251 {-# INLINE parseJSON #-}
1619− parseJSON Null = pure Proxy
1620− parseJSON v = typeMismatch "Proxy" v
2252+ parseJSON = fromNull "Proxy" Proxy
16212253
2254+fromNull :: String -> a -> Value -> Parser a
2255+fromNull _ a Null = pure a
2256+fromNull c _ v = prependContext c (typeMismatch "Null" v)
2257+
2258+instance FromJSON2 Tagged where
2259+ liftParseJSON2 _ _ p _ = fmap Tagged . p
2260+ {-# INLINE liftParseJSON2 #-}
16222261
16232262instance FromJSON1 (Tagged a) where
16242263 liftParseJSON p _ = fmap Tagged . p
@@ -1641,10 +2280,7 @@ instance (FromJSON a, FromJSON b, FromJSON c) => FromJSONKey (a,b,c)
16412280instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a,b,c,d)
16422281
16432282instance FromJSONKey Char where
1644− fromJSONKey = FromJSONKeyTextParser $ \t ->
1645− if T.length t == 1
1646− then return (T.index t 0)
1647− else typeMismatch "Expected Char but String didn't contain exactly one character" (String t)
2283+ fromJSONKey = FromJSONKeyTextParser parseChar
16482284 fromJSONKeyList = FromJSONKeyText T.unpack
16492285
16502286instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where