@@ -1,28 +1,29 @@
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 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"
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+
1921#include "overlapping-compat.h"
2022
2123-- TODO: Drop this when we remove support for Data.Attoparsec.Number
2224{-# OPTIONS_GHC -fno-warn-deprecations #-}
2325
24−module Data.Aeson.Types.FromJSON
25− (
26+module Data.Aeson.Types.FromJSON (
2627 -- * Core JSON classes
2728 FromJSON(..)
2829 -- * Liftings to unary and binary type constructors
@@ -32,7 +33,6 @@ module Data.Aeson.Types.FromJSON
3233 , parseJSON2
3334 -- * Generic JSON classes
3435 , GFromJSON(..)
35− , FromArgs(..)
3636 , genericParseJSON
3737 , genericLiftParseJSON
3838 -- * Classes and types for map keys
@@ -42,121 +42,106 @@ module Data.Aeson.Types.FromJSON
4242 , coerceFromJSONKeyFunction
4343 , mapFromJSONKeyFunction
4444
45− , GFromJSONKey()
46− , genericFromJSONKey
47−
4845 -- * List functions
4946 , listParser
5047
51− -- * Inspecting @'Value's@
48+ -- * Inspecting @'Value's@
5249 , withObject
5350 , withText
5451 , withArray
52+ , withNumber
5553 , withScientific
5654 , withBool
57− , withEmbeddedJSON
5855
5956 -- * Functions
6057 , fromJSON
6158 , ifromJSON
62− , typeMismatch
63− , unexpected
64− , parseField
65− , parseFieldMaybe
66− , parseFieldMaybe'
67− , explicitParseField
68− , explicitParseFieldMaybe
69− , explicitParseFieldMaybe'
70− , parseIndexedJSON
71− -- ** Operators
7259 , (.:)
7360 , (.:?)
7461 , (.:!)
7562 , (.!=)
63+ , typeMismatch
7664
7765 -- * Internal
7866 , parseOptionalFieldWith
7967 ) where
8068
81−import Prelude.Compat
69+import Prelude ()
70+import Prelude.Compat hiding (foldr)
8271
83−import Control.Applicative ((<|>), Const(..), liftA2)
84−import Control.Monad (zipWithM)
8572import Data.Aeson.Internal.Functions (mapKey)
86−import Data.Aeson.Parser.Internal (eitherDecodeWith, jsonEOF)
8773import Data.Aeson.Types.Generic
8874import Data.Aeson.Types.Internal
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 (..))
75+
76+import qualified Data.Aeson.Parser.Time as Time
77+import qualified Data.Attoparsec.ByteString.Char8 as A (endOfInput, parseOnly,
78+ scientific)
79+
80+import Control.Applicative (Const (..), (<|>))
81+import Control.Monad ((<=<))
82+import Data.Attoparsec.Number (Number (..))
83+import Data.Bits (unsafeShiftR)
84+import Data.Fixed (Fixed, HasResolution)
85+import Data.Functor.Compose (Compose (..))
86+import Data.Functor.Identity (Identity (..))
87+import Data.Functor.Product (Product (..))
88+import Data.Functor.Sum (Sum (..))
89+import Data.Hashable (Hashable (..))
90+import Data.Int (Int16, Int32, Int64, Int8)
91+import Data.List.NonEmpty (NonEmpty (..))
92+import Data.Maybe (fromMaybe)
93+import Data.Monoid (Dual (..), First (..), Last (..), (<>))
94+import Data.Proxy (Proxy (..))
95+import Data.Ratio (Ratio, (%))
96+import Data.Scientific (Scientific)
97+import Data.Tagged (Tagged (..))
98+import Data.Text (Text, pack, unpack)
99+import Data.Time (Day, LocalTime, NominalDiffTime, TimeOfDay,
100+ UTCTime, ZonedTime)
101+import Data.Time.Format (parseTime)
102+import Data.Time.Locale.Compat (defaultTimeLocale)
103+import Data.Traversable as Tr (sequence)
104+import Data.Vector (Vector)
105+import Data.Version (Version, parseVersion)
106+import Data.Word (Word16, Word32, Word64, Word8)
107+import Foreign.Storable (Storable)
117108import GHC.Generics
118−import Numeric.Natural (Natural)
109+import Numeric.Natural (Natural)
119110import Text.ParserCombinators.ReadP (readP_to_S)
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
111+
112+import qualified Data.DList as DList
113+import qualified Data.HashMap.Strict as H
114+import qualified Data.HashSet as HashSet
115+import qualified Data.IntMap as IntMap
116+import qualified Data.IntSet as IntSet
117+import qualified Data.Map as M
118+import qualified Data.Scientific as Scientific
119+import qualified Data.Sequence as Seq
120+import qualified Data.Set as Set
121+import qualified Data.Text as T
122+import qualified Data.Text.Encoding as T
123+import qualified Data.Text.Lazy as LT
124+import qualified Data.Tree as Tree
125+import qualified Data.Vector as V
126+import qualified Data.Vector.Generic as VG
142127import qualified Data.Vector.Primitive as VP
143−import qualified Data.Vector.Storable as VS
144−import qualified Data.Vector.Unboxed as VU
128+import qualified Data.Vector.Storable as VS
129+import qualified Data.Vector.Unboxed as VU
145130
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
131+import Unsafe.Coerce (unsafeCoerce)
150132
151−#if MIN_VERSION_primitive(0,6,4)
152−#if !MIN_VERSION_primitive(0,7,0)
153−import qualified Data.Primitive.UnliftedArray as PM
133+#ifndef HAS_COERCIBLE
134+#define HAS_COERCIBLE (__GLASGOW_HASKELL__ >= 707)
154135#endif
155−import qualified Data.Primitive.PrimArray as PM
156−#endif
157−
158136
137+#if HAS_COERCIBLE
159138import Data.Coerce (Coercible, coerce)
139+coerce' :: Coercible a b => a -> b
140+coerce' = coerce
141+#else
142+coerce' :: a -> b
143+coerce' = unsafeCoerce
144+#endif
160145
161146parseIndexedJSON :: (Value -> Parser a) -> Int -> Value -> Parser a
162147parseIndexedJSON p idx value = p value <?> Index idx
@@ -165,7 +150,7 @@ parseIndexedJSON p idx value = p value <?> Index idx
165150parseIndexedJSONPair :: (Value -> Parser a) -> (Value -> Parser b) -> Int -> Value -> Parser (a, b)
166151parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
167152 where
168− p = withArray "(k, v)" $ \ab ->
153+ p = withArray "(k,v)" $ \ab ->
169154 let n = V.length ab
170155 in if n == 2
171156 then (,) <$> parseJSONElemAtIndex keyParser 0 ab
@@ -177,57 +162,33 @@ parseIndexedJSONPair keyParser valParser idx value = p value <?> Index idx
177162parseJSONElemAtIndex :: (Value -> Parser a) -> Int -> V.Vector Value -> Parser a
178163parseJSONElemAtIndex p idx ary = p (V.unsafeIndex ary idx) <?> Index idx
179164
165+scientificToNumber :: Scientific -> Number
166+scientificToNumber s
167+ | e < 0 = D $ Scientific.toRealFloat s
168+ | otherwise = I $ c * 10 ^ e
169+ where
170+ e = Scientific.base10Exponent s
171+ c = Scientific.coefficient s
172+{-# INLINE scientificToNumber #-}
173+
180174parseRealFloat :: RealFloat a => String -> Value -> Parser a
181−parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
182−parseRealFloat _ Null = pure (0/0)
183−parseRealFloat name v = prependContext name (unexpected v)
175+parseRealFloat _ (Number s) = pure $ Scientific.toRealFloat s
176+parseRealFloat _ Null = pure (0/0)
177+parseRealFloat expected v = typeMismatch expected v
184178{-# INLINE parseRealFloat #-}
185179
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−
193180parseIntegral :: Integral a => String -> Value -> Parser a
194−parseIntegral name =
195− prependContext name . withBoundedScientific' parseIntegralFromScientific
181+parseIntegral expected = withScientific expected $ pure . truncate
196182{-# INLINE parseIntegral #-}
197183
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−
210184parseScientificText :: Text -> Parser Scientific
211185parseScientificText
212186 = either fail pure
213187 . A.parseOnly (A.scientific <* A.endOfInput)
214188 . T.encodeUtf8
215189
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
190+parseIntegralText :: Integral a => Text -> Parser a
191+parseIntegralText t = truncate <$> parseScientificText t
231192
232193parseOptionalFieldWith :: (Value -> Parser (Maybe a))
233194 -> Object -> Text -> Parser (Maybe a)
@@ -246,21 +207,16 @@ class GFromJSON arity f where
246207 -- | This method (applied to 'defaultOptions') is used as the
247208 -- default generic implementation of 'parseJSON' (if the @arity@ is 'Zero')
248209 -- or 'liftParseJSON' (if the @arity@ is 'One').
249− gParseJSON :: Options -> FromArgs arity a -> Value -> Parser (f a)
250−
251−-- | A 'FromArgs' value either stores nothing (for 'FromJSON') or it stores the
252−-- two function arguments that decode occurrences of the type parameter (for
253−-- 'FromJSON1').
254−data FromArgs arity a where
255− NoFromArgs :: FromArgs Zero a
256− From1Args :: (Value -> Parser a) -> (Value -> Parser [a]) -> FromArgs One a
210+ gParseJSON :: Options -> Proxy arity
211+ -> (Value -> Parser a) -> (Value -> Parser [a])
212+ -> Value -> Parser (f a)
257213
258214-- | A configurable generic JSON decoder. This function applied to
259215-- 'defaultOptions' is used as the default for 'parseJSON' when the
260216-- type is an instance of 'Generic'.
261217genericParseJSON :: (Generic a, GFromJSON Zero (Rep a))
262218 => Options -> Value -> Parser a
263−genericParseJSON opts = fmap to . gParseJSON opts NoFromArgs
219+genericParseJSON opts = fmap to . gParseJSON opts proxyZero undefined undefined
264220
265221-- | A configurable generic JSON decoder. This function applied to
266222-- 'defaultOptions' is used as the default for 'liftParseJSON' when the
@@ -268,7 +224,7 @@ genericParseJSON opts = fmap to . gParseJSON opts NoFromArgs
268224genericLiftParseJSON :: (Generic1 f, GFromJSON One (Rep1 f))
269225 => Options -> (Value -> Parser a) -> (Value -> Parser [a])
270226 -> Value -> Parser (f a)
271−genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
227+genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts proxyOne pj pjl
272228
273229-------------------------------------------------------------------------------
274230-- Class
@@ -287,21 +243,14 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
287243--
288244-- The basic ways to signal a failed conversion are as follows:
289245--
290−-- * 'fail' yields a custom error message: it is the recommended way of
291−-- reporting a failure;
246+-- * 'empty' and 'mzero' work, but are terse and uninformative
292247--
293−-- * 'Control.Applicative.empty' (or 'Control.Monad.mzero') is uninformative:
294−-- use it when the error is meant to be caught by some @('<|>')@;
248+-- * 'fail' yields a custom error message
295249--
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.
250+-- * 'typeMismatch' produces an informative message for cases when the
251+-- value encountered is not of the expected type
300252--
301−-- 'prependFailure' (or 'modifyFailure') add more information to a parser's
302−-- error messages.
303−--
304−-- An example type and instance using 'typeMismatch' and 'prependFailure':
253+-- An example type and instance:
305254--
306255-- @
307256-- \-- Allow ourselves to write 'Text' literals.
@@ -309,30 +258,15 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
309258--
310259-- data Coord = Coord { x :: Double, y :: Double }
311260--
312−-- instance 'FromJSON' Coord where
313−-- 'parseJSON' ('Object' v) = Coord
314−-- '<$>' v '.:' \"x\"
315−-- '<*>' v '.:' \"y\"
261+-- instance FromJSON Coord where
262+-- parseJSON ('Object' v) = Coord '<$>'
263+-- v '.:' \"x\" '<*>'
264+-- v '.:' \"y\"
316265--
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\"
266+-- \-- We do not expect a non-'Object' value here.
267+-- \-- We could use 'mzero' to fail, but 'typeMismatch'
268+-- \-- gives a much more informative error message.
269+-- parseJSON invalid = 'typeMismatch' \"Coord\" invalid
336270-- @
337271--
338272-- Instead of manually writing your 'FromJSON' instance, there are two options
@@ -340,7 +274,7 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
340274--
341275-- * "Data.Aeson.TH" provides Template Haskell functions which will derive an
342276-- instance at compile time. The generated instance is optimized for your type
343−-- so it will probably be more efficient than the following option.
277+-- so will probably be more efficient than the following two options:
344278--
345279-- * The compiler can provide a default generic implementation for
346280-- 'parseJSON'.
@@ -358,21 +292,18 @@ genericLiftParseJSON opts pj pjl = fmap to1 . gParseJSON opts (From1Args pj pjl)
358292--
359293-- data Coord = Coord { x :: Double, y :: Double } deriving 'Generic'
360294--
361−-- instance 'FromJSON' Coord
295+-- instance FromJSON Coord
362296-- @
363297--
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:
298+-- If @DefaultSignatures@ doesn't give exactly the results you want,
299+-- you can customize the generic decoding with only a tiny amount of
300+-- effort, using 'genericParseJSON' with your preferred 'Options':
367301--
368302-- @
369−-- customOptions = 'defaultOptions'
370−-- { 'fieldLabelModifier' = 'map' 'Data.Char.toUpper'
371−-- }
372−--
373−-- instance 'FromJSON' Coord where
374−-- 'parseJSON' = 'genericParseJSON' customOptions
303+-- instance FromJSON Coord where
304+-- parseJSON = 'genericParseJSON' 'defaultOptions'
375305-- @
306+
376307class FromJSON a where
377308 parseJSON :: Value -> Parser a
378309
@@ -380,89 +311,61 @@ class FromJSON a where
380311 parseJSON = genericParseJSON defaultOptions
381312
382313 parseJSONList :: Value -> Parser [a]
383− parseJSONList = withArray "[]" $ \a ->
384− zipWithM (parseIndexedJSON parseJSON) [0..]
314+ parseJSONList (Array a)
315+ = sequence
316+ . zipWith (parseIndexedJSON parseJSON) [0..]
385317 . V.toList
386318 $ a
387319
320+ parseJSONList v = typeMismatch "[a]" v
321+
388322-------------------------------------------------------------------------------
389323-- Classes and types for map keys
390324-------------------------------------------------------------------------------
391325
392−-- | Read the docs for 'ToJSONKey' first. This class is a conversion
393−-- in the opposite direction. If you have a newtype wrapper around 'Text',
394−-- the recommended way to define instances is with generalized newtype deriving:
395−--
396−-- > newtype SomeId = SomeId { getSomeId :: Text }
397−-- > deriving (Eq,Ord,Hashable,FromJSONKey)
398−--
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−-- @
409326class FromJSONKey a where
410− -- | Strategy for parsing the key of a map-like container.
411327 fromJSONKey :: FromJSONKeyFunction a
412328 default fromJSONKey :: FromJSON a => FromJSONKeyFunction a
413329 fromJSONKey = FromJSONKeyValue parseJSON
414330
415− -- | This is similar in spirit to the 'readList' method of 'Read'.
416− -- It makes it possible to give 'String' keys special treatment
417− -- without using @OverlappingInstances@. End users should always
418− -- be able to use the default implementation of this method.
419331 fromJSONKeyList :: FromJSONKeyFunction [a]
420332 default fromJSONKeyList :: FromJSON a => FromJSONKeyFunction [a]
421333 fromJSONKeyList = FromJSONKeyValue parseJSON
422334
423−-- | With GHC 7.8+ we carry around @'Coercible' 'Text' a@ dictionary,
424−-- to give us an assurance that the program will not segfault.
425−-- Unfortunately we cannot enforce that the 'Eq' instances or the
426−-- 'Hashable' instances for 'Text' and @a@ agree.
335+-- | With GHC 7.8 + we carry around 'Coercible Text a' dictionary,
336+-- to have even some amount of safety net.
337+-- Unfortunately we cannot enforce that 'Hashable' instance agree on the type level
427338--
428−-- At the moment this type is intentionally not exported. 'FromJSONKeyFunction'
429−-- can be inspected, but cannot be constructed.
339+-- ATM this type is intentionally not exported. FromJSONKeyFunction can be inspected,
340+-- but cannot be constructed.
430341data CoerceText a where
342+#if HAS_COERCIBLE
431343 CoerceText :: Coercible Text a => CoerceText a
344+#else
345+ CoerceText :: CoerceText a
346+#endif
432347
433−-- | This type is related to 'ToJSONKeyFunction'. If 'FromJSONKeyValue' is used in the
434−-- 'FromJSONKey' instance, then 'ToJSONKeyValue' should be used in the 'ToJSONKey'
435−-- instance. The other three data constructors for this type all correspond to
436−-- 'ToJSONKeyText'. Strictly speaking, 'FromJSONKeyTextParser' is more powerful than
437−-- 'FromJSONKeyText', which is in turn more powerful than 'FromJSONKeyCoerce'.
438−-- For performance reasons, these exist as three options instead of one.
439348data FromJSONKeyFunction a
440349 = FromJSONKeyCoerce !(CoerceText a)
441− -- ^ uses 'coerce' ('unsafeCoerce' in older GHCs)
442350 | FromJSONKeyText !(Text -> a)
443− -- ^ conversion from 'Text' that always succeeds
444351 | FromJSONKeyTextParser !(Text -> Parser a)
445− -- ^ conversion from 'Text' that may fail
446352 | FromJSONKeyValue !(Value -> Parser a)
447− -- ^ conversion for non-textual keys
448353
449−-- | Only law abiding up to interpretation
450354instance Functor FromJSONKeyFunction where
451− fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce)
355+ fmap h (FromJSONKeyCoerce CoerceText) = FromJSONKeyText (h . coerce')
452356 fmap h (FromJSONKeyText f) = FromJSONKeyText (h . f)
453357 fmap h (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap h . f)
454358 fmap h (FromJSONKeyValue f) = FromJSONKeyValue (fmap h . f)
455359
456360-- | Construct 'FromJSONKeyFunction' for types coercible from 'Text'. This
457361-- conversion is still unsafe, as 'Hashable' and 'Eq' instances of @a@ should be
458−-- compatible with 'Text' i.e. hash values should be equal for wrapped values as well.
459−-- This property will always be maintained if the 'Hashable' and 'Eq' instances
460−-- are derived with generalized newtype deriving.
461362-- compatible with 'Text' i.e. hash values be equal for wrapped values as well.
462363--
463364-- On pre GHC 7.8 this is unconstrainted function.
464365fromJSONKeyCoerce ::
366+#if HAS_COERCIBLE
465367 Coercible Text a =>
368+#endif
466369 FromJSONKeyFunction a
467370fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
468371
@@ -470,91 +373,60 @@ fromJSONKeyCoerce = FromJSONKeyCoerce CoerceText
470373--
471374-- See note on 'fromJSONKeyCoerce'.
472375coerceFromJSONKeyFunction ::
376+#if HAS_COERCIBLE
473377 Coercible a b =>
378+#endif
474379 FromJSONKeyFunction a -> FromJSONKeyFunction b
380+#if HAS_COERCIBLE
475381coerceFromJSONKeyFunction = coerce
382+#else
383+coerceFromJSONKeyFunction (FromJSONKeyCoerce CoerceText) = FromJSONKeyCoerce CoerceText
384+coerceFromJSONKeyFunction (FromJSONKeyText f) = FromJSONKeyText (coerce' . f)
385+coerceFromJSONKeyFunction (FromJSONKeyTextParser f) = FromJSONKeyTextParser (fmap coerce' . f)
386+coerceFromJSONKeyFunction (FromJSONKeyValue f) = FromJSONKeyValue (fmap coerce' . f)
387+#endif
476388
477389{-# RULES
478390 "FromJSONKeyCoerce: fmap id" forall (x :: FromJSONKeyFunction a).
479391 fmap id x = x
480392 #-}
393+#if HAS_COERCIBLE
481394{-# RULES
482395 "FromJSONKeyCoerce: fmap coerce" forall x .
483396 fmap coerce x = coerceFromJSONKeyFunction x
484397 #-}
398+#endif
485399
486400-- | Same as 'fmap'. Provided for the consistency with 'ToJSONKeyFunction'.
487401mapFromJSONKeyFunction :: (a -> b) -> FromJSONKeyFunction a -> FromJSONKeyFunction b
488402mapFromJSONKeyFunction = fmap
489403
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−
519404-------------------------------------------------------------------------------
520405-- Functions needed for documentation
521406-------------------------------------------------------------------------------
522407
523408-- | Fail parsing due to a type mismatch, with a descriptive message.
524409--
525−-- The following wrappers should generally be prefered:
526−-- 'withObject', 'withArray', 'withText', 'withBool'.
527−--
528−-- ==== Error message example
410+-- Example usage:
529411--
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\"@).
412+-- @
413+-- instance FromJSON Coord where
414+-- parseJSON ('Object' v) = {- type matches, life is good -}
415+-- parseJSON wat = 'typeMismatch' \"Coord\" wat
416+-- @
417+typeMismatch :: String -- ^ The name of the type you are trying to parse.
535418 -> Value -- ^ The actual value encountered.
536419 -> Parser a
537420typeMismatch expected actual =
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"
421+ fail $ "expected " ++ expected ++ ", encountered " ++ name
422+ where
423+ name = case actual of
424+ Object _ -> "Object"
425+ Array _ -> "Array"
426+ String _ -> "String"
427+ Number _ -> "Number"
428+ Bool _ -> "Boolean"
429+ Null -> "Null"
558430
559431-------------------------------------------------------------------------------
560432-- Lifings of FromJSON and ToJSON to unary and binary type constructors
@@ -567,7 +439,7 @@ typeOf v = case v of
567439--
568440-- * "Data.Aeson.TH" provides Template Haskell functions which will derive an
569441-- instance at compile time. The generated instance is optimized for your type
570−-- so it will probably be more efficient than the following option.
442+-- so will probably be more efficient than the following two options:
571443--
572444-- * The compiler can provide a default generic implementation for
573445-- 'liftParseJSON'.
@@ -585,20 +457,16 @@ typeOf v = case v of
585457--
586458-- data Pair a b = Pair { pairFst :: a, pairSnd :: b } deriving 'Generic1'
587459--
588−-- instance 'FromJSON' a => 'FromJSON1' (Pair a)
460+-- instance FromJSON a => FromJSON1 (Pair a)
589461-- @
590462--
591−-- If the default implementation doesn't give exactly the results you want,
463+-- If @DefaultSignatures@ doesn't give exactly the results you want,
592464-- you can customize the generic decoding with only a tiny amount of
593465-- effort, using 'genericLiftParseJSON' with your preferred 'Options':
594466--
595467-- @
596−-- customOptions = 'defaultOptions'
597−-- { 'fieldLabelModifier' = 'map' 'Data.Char.toUpper'
598−-- }
599−--
600−-- instance 'FromJSON' a => 'FromJSON1' (Pair a) where
601−-- 'liftParseJSON' = 'genericLiftParseJSON' customOptions
468+-- instance FromJSON a => FromJSON1 (Pair a) where
469+-- liftParseJSON = 'genericLiftParseJSON' 'defaultOptions'
602470-- @
603471class FromJSON1 f where
604472 liftParseJSON :: (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (f a)
@@ -635,8 +503,9 @@ class FromJSON2 f where
635503 -> (Value -> Parser b)
636504 -> (Value -> Parser [b])
637505 -> Value -> Parser [f a b]
638− liftParseJSONList2 fa ga fb gb = withArray "[]" $ \vals ->
639− fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
506+ liftParseJSONList2 fa ga fb gb v = case v of
507+ Array vals -> fmap V.toList (V.mapM (liftParseJSON2 fa ga fb gb) vals)
508+ _ -> typeMismatch "[a]" v
640509
641510-- | Lift the standard 'parseJSON' function through the type constructor.
642511parseJSON2 :: (FromJSON2 f, FromJSON a, FromJSON b) => Value -> Parser (f a b)
@@ -647,10 +516,9 @@ parseJSON2 = liftParseJSON2 parseJSON parseJSONList parseJSON parseJSONList
647516-- List functions
648517-------------------------------------------------------------------------------
649518
650−-- | Helper function to use with 'liftParseJSON'. See 'Data.Aeson.ToJSON.listEncoding'.
651519listParser :: (Value -> Parser a) -> Value -> Parser [a]
652520listParser f (Array xs) = fmap V.toList (V.mapM f xs)
653−listParser _ v = typeMismatch "Array" v
521+listParser _ v = typeMismatch "[a]" v
654522{-# INLINE listParser #-}
655523
656524-------------------------------------------------------------------------------
@@ -668,139 +536,48 @@ instance (FromJSON a) => FromJSON [a] where
668536-- Functions
669537-------------------------------------------------------------------------------
670538
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"
539+-- | @withObject expected f value@ applies @f@ to the 'Object' when @value@ is an @Object@
540+-- and fails using @'typeMismatch' expected@ otherwise.
686541withObject :: String -> (Object -> Parser a) -> Value -> Parser a
687−withObject _ f (Object obj) = f obj
688−withObject name _ v = prependContext name (typeMismatch "Object" v)
542+withObject _ f (Object obj) = f obj
543+withObject expected _ v = typeMismatch expected v
689544{-# INLINE withObject #-}
690545
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"
546+-- | @withText expected f value@ applies @f@ to the 'Text' when @value@ is a @String@
547+-- and fails using @'typeMismatch' expected@ otherwise.
698548withText :: String -> (Text -> Parser a) -> Value -> Parser a
699−withText _ f (String txt) = f txt
700−withText name _ v = prependContext name (typeMismatch "String" v)
549+withText _ f (String txt) = f txt
550+withText expected _ v = typeMismatch expected v
701551{-# INLINE withText #-}
702552
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"
553+-- | @withArray expected f value@ applies @f@ to the 'Array' when @value@ is an @Array@
554+-- and fails using @'typeMismatch' expected@ otherwise.
710555withArray :: String -> (Array -> Parser a) -> Value -> Parser a
711−withArray _ f (Array arr) = f arr
712−withArray name _ v = prependContext name (typeMismatch "Array" v)
556+withArray _ f (Array arr) = f arr
557+withArray expected _ v = typeMismatch expected v
713558{-# INLINE withArray #-}
714559
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"
560+-- | @withNumber expected f value@ applies @f@ to the 'Number' when @value@ is a 'Number'.
561+-- and fails using @'typeMismatch' expected@ otherwise.
562+withNumber :: String -> (Number -> Parser a) -> Value -> Parser a
563+withNumber expected f = withScientific expected (f . scientificToNumber)
564+{-# INLINE withNumber #-}
565+{-# DEPRECATED withNumber "Use withScientific instead" #-}
566+
567+-- | @withScientific expected f value@ applies @f@ to the 'Scientific' number when @value@ is a 'Number'.
568+-- and fails using @'typeMismatch' expected@ otherwise.
728569withScientific :: String -> (Scientific -> Parser a) -> Value -> Parser a
729−withScientific _ f (Number scientific) = f scientific
730−withScientific name _ v = prependContext name (typeMismatch "Number" v)
570+withScientific _ f (Number scientific) = f scientific
571+withScientific expected _ v = typeMismatch expected v
731572{-# INLINE withScientific #-}
732573
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"
574+-- | @withBool expected f value@ applies @f@ to the 'Bool' when @value@ is a @Bool@
575+-- and fails using @'typeMismatch' expected@ otherwise.
789576withBool :: String -> (Bool -> Parser a) -> Value -> Parser a
790−withBool _ f (Bool arr) = f arr
791−withBool name _ v = prependContext name (typeMismatch "Boolean" v)
577+withBool _ f (Bool arr) = f arr
578+withBool expected _ v = typeMismatch expected v
792579{-# INLINE withBool #-}
793580
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−
804581-- | Convert a value from JSON, failing if the types do not match.
805582fromJSON :: (FromJSON a) => Value -> Result a
806583fromJSON = parse parseJSON
@@ -819,68 +596,32 @@ ifromJSON = iparse parseJSON
819596-- in an object for it to be valid. If the key and value are
820597-- optional, use '.:?' instead.
821598(.:) :: (FromJSON a) => Object -> Text -> Parser a
822−(.:) = explicitParseField parseJSON
599+obj .: key = case H.lookup key obj of
600+ Nothing -> fail $ "key " ++ show key ++ " not present"
601+ Just v -> parseJSON v <?> Key key
823602{-# INLINE (.:) #-}
824603
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.
604+-- | Retrieve the value associated with the given key of an 'Object'.
605+-- The result is 'Nothing' if the key is not present, or 'empty' if
606+-- the value cannot be converted to the desired type.
828607--
829608-- This accessor is most useful if the key and value can be absent
830609-- from an object without affecting its validity. If the key and
831610-- value are mandatory, use '.:' instead.
832611(.:?) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
833−(.:?) = explicitParseFieldMaybe parseJSON
612+obj .:? key = case H.lookup key obj of
613+ Nothing -> pure Nothing
614+ Just v -> parseJSON v <?> Key key
834615{-# INLINE (.:?) #-}
835616
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'.
617+-- | Like '.:?', but the resulting parser will fail,
618+-- if the key is present but is 'Null'.
842619(.:!) :: (FromJSON a) => Object -> Text -> Parser (Maybe a)
843−(.:!) = explicitParseFieldMaybe' parseJSON
620+obj .:! key = case H.lookup key obj of
621+ Nothing -> pure Nothing
622+ Just v -> Just <$> parseJSON v <?> Key key
844623{-# INLINE (.:!) #-}
845624
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 <$> p v <?> Key key
882−{-# INLINE explicitParseFieldMaybe' #-}
883−
884625-- | Helper for use in combination with '.:?' to provide default
885626-- values for optional JSON object fields.
886627--
@@ -903,554 +644,317 @@ pmval .!= val = fromMaybe val <$> pmval
903644-- Generic parseJSON
904645-------------------------------------------------------------------------------
905646
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−
911647instance OVERLAPPABLE_ (GFromJSON arity a) => GFromJSON arity (M1 i c a) where
912648 -- Meta-information, which is not handled elsewhere, is just added to the
913649 -- parsed value:
914− gParseJSON opts fargs = fmap M1 . gParseJSON opts fargs
915−
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
650+ gParseJSON opts pa pj pjl = fmap M1 . gParseJSON opts pa pj pjl
946651
947652instance (FromJSON a) => GFromJSON arity (K1 i a) where
948653 -- Constant values are decoded using their FromJSON instance:
949− gParseJSON _opts _ = fmap K1 . parseJSON
654+ gParseJSON _opts _ _ _ = fmap K1 . parseJSON
950655
951656instance GFromJSON One Par1 where
952657 -- Direct occurrences of the last type parameter are decoded with the
953658 -- function passed in as an argument:
954− gParseJSON _opts (From1Args pj _) = fmap Par1 . pj
659+ gParseJSON _opts _ pj _ = fmap Par1 . pj
955660
956661instance (FromJSON1 f) => GFromJSON One (Rec1 f) where
957662 -- Recursive occurrences of the last type parameter are decoded using their
958663 -- FromJSON1 instance:
959− gParseJSON _opts (From1Args pj pjl) = fmap Rec1 . liftParseJSON pj pjl
664+ gParseJSON _opts _ pj pjl = fmap Rec1 . liftParseJSON pj pjl
665+
666+instance GFromJSON arity U1 where
667+ -- Empty constructors are expected to be encoded as an empty array:
668+ gParseJSON _opts _ _ _ v
669+ | isEmptyArray v = pure U1
670+ | otherwise = typeMismatch "unit constructor (U1)" v
671+
672+instance (ConsFromJSON arity a) => GFromJSON arity (C1 c a) where
673+ -- Constructors need to be decoded differently depending on whether they're
674+ -- a record or not. This distinction is made by consParseJSON:
675+ gParseJSON opts pa pj pjl = fmap M1 . consParseJSON opts pa pj pjl
676+
677+instance ( FromProduct arity a, FromProduct arity b
678+ , ProductSize a, ProductSize b
679+ ) => GFromJSON arity (a :*: b) where
680+ -- Products are expected to be encoded to an array. Here we check whether we
681+ -- got an array of the same size as the product, then parse each of the
682+ -- product's elements using parseProduct:
683+ gParseJSON opts pa pj pjl = withArray "product (:*:)" $ \arr ->
684+ let lenArray = V.length arr
685+ lenProduct = (unTagged2 :: Tagged2 (a :*: b) Int -> Int)
686+ productSize in
687+ if lenArray == lenProduct
688+ then parseProduct opts pa arr 0 lenProduct pj pjl
689+ else fail $ "When expecting a product of " ++ show lenProduct ++
690+ " values, encountered an Array of " ++ show lenArray ++
691+ " elements instead"
692+
693+instance ( AllNullary (a :+: b) allNullary
694+ , ParseSum arity (a :+: b) allNullary
695+ ) => GFromJSON arity (a :+: b) where
696+ -- If all constructors of a sum datatype are nullary and the
697+ -- 'allNullaryToStringTag' option is set they are expected to be
698+ -- encoded as strings. This distinction is made by 'parseSum':
699+ gParseJSON opts pa pj pjl =
700+ (unTagged :: Tagged allNullary (Parser ((a :+: b) d)) ->
701+ (Parser ((a :+: b) d)))
702+ . parseSum opts pa pj pjl
960703
961704instance (FromJSON1 f, GFromJSON One g) => GFromJSON One (f :.: g) where
962705 -- If an occurrence of the last type parameter is nested inside two
963706 -- composed types, it is decoded by using the outermost type's FromJSON1
964707 -- instance to generically decode the innermost type:
965− gParseJSON opts fargs =
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
708+ gParseJSON opts pa pj pjl =
709+ let gpj = gParseJSON opts pa pj pjl in
710+ fmap Comp1 . liftParseJSON gpj (listParser gpj)
1013711
1014712--------------------------------------------------------------------------------
1015713
1016714class ParseSum arity f allNullary where
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
715+ parseSum :: Options -> Proxy arity
716+ -> (Value -> Parser a) -> (Value -> Parser [a])
717+ -> Value -> Tagged allNullary (Parser (f a))
718+
719+instance ( SumFromString (a :+: b)
720+ , FromPair arity (a :+: b)
721+ , FromTaggedObject arity (a :+: b)
722+ ) => ParseSum arity (a :+: b) True where
723+ parseSum opts pa pj pjl
724+ | allNullaryToStringTag opts = Tagged . parseAllNullarySum opts
725+ | otherwise = Tagged . parseNonAllNullarySum opts pa pj pjl
726+
727+instance ( FromPair arity (a :+: b)
728+ , FromTaggedObject arity (a :+: b)
729+ ) => ParseSum arity (a :+: b) False where
730+ parseSum opts pa pj pjl = Tagged . parseNonAllNullarySum opts pa pj pjl
1037731
1038732--------------------------------------------------------------------------------
1039733
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])
734+parseAllNullarySum :: SumFromString f => Options -> Value -> Parser (f a)
735+parseAllNullarySum opts = withText "Text" $ \key ->
736+ maybe (notFound key) return $
737+ parseSumFromString opts key
1062738
1063739class SumFromString f where
1064− parseSumFromString :: (String -> String) -> Text -> Maybe (f a)
740+ parseSumFromString :: Options -> Text -> Maybe (f a)
1065741
1066742instance (SumFromString a, SumFromString b) => SumFromString (a :+: b) where
1067743 parseSumFromString opts key = (L1 <$> parseSumFromString opts key) <|>
1068744 (R1 <$> parseSumFromString opts key)
1069745
1070746instance (Constructor c) => SumFromString (C1 c U1) where
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)
1076−
1077−-- For genericFromJSONKey
1078−instance SumFromString a => SumFromString (D1 d a) where
1079− parseSumFromString modifier key = M1 <$> parseSumFromString modifier key
1080−
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
747+ parseSumFromString opts key | key == name = Just $ M1 U1
748+ | otherwise = Nothing
749+ where
750+ name = pack $ constructorTagModifier opts $
751+ conName (undefined :: t c U1 p)
1111752
1112753--------------------------------------------------------------------------------
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 :* _) =
754+
755+parseNonAllNullarySum :: ( FromPair arity (a :+: b)
756+ , FromTaggedObject arity (a :+: b)
757+ ) => Options -> Proxy arity
758+ -> (Value -> Parser c) -> (Value -> Parser [c])
759+ -> Value -> Parser ((a :+: b) c)
760+parseNonAllNullarySum opts pa pj pjl =
1121761 case sumEncoding opts of
1122762 TaggedObject{..} ->
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])
763+ withObject "Object" $ \obj -> do
764+ tag <- obj .: pack tagFieldName
765+ fromMaybe (notFound tag) $
766+ parseFromTaggedObject opts pa contentsFieldName obj pj pjl tag
1133767
1134768 ObjectWithSingleField ->
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
769+ withObject "Object" $ \obj ->
770+ case H.toList obj of
771+ [pair@(tag, _)] -> fromMaybe (notFound tag) $
772+ parsePair opts pa pj pjl pair
773+ _ -> fail "Object doesn't have a single field"
1145774
1146775 TwoElemArray ->
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
1161−
1162− UntaggedValue -> parseUntaggedValue p
1163− where
1164− failWith_ = failWithCTags tname (constructorTagModifier opts)
776+ withArray "Array" $ \arr ->
777+ if V.length arr == 2
778+ then case V.unsafeIndex arr 0 of
779+ String tag -> fromMaybe (notFound tag) $
780+ parsePair opts pa pj pjl (tag, V.unsafeIndex arr 1)
781+ _ -> fail "First element is not a String"
782+ else fail "Array doesn't have 2 elements"
1165783
1166784--------------------------------------------------------------------------------
1167785
1168786class FromTaggedObject arity f where
1169− -- The first two components of the parameter tuple are: the constructor tag
1170− -- to match against, and the contents field name.
1171− parseFromTaggedObject
1172− :: Text :* String :* TypeName :* Options :* FromArgs arity a
1173− -> Object
1174− -> Maybe (Parser (f a))
787+ parseFromTaggedObject :: Options -> Proxy arity
788+ -> String -> Object
789+ -> (Value -> Parser a) -> (Value -> Parser [a])
790+ -> Text -> Maybe (Parser (f a))
1175791
1176792instance ( FromTaggedObject arity a, FromTaggedObject arity b) =>
1177793 FromTaggedObject arity (a :+: b) where
1178− parseFromTaggedObject p obj =
1179− (fmap L1 <$> parseFromTaggedObject p obj) <|>
1180− (fmap R1 <$> parseFromTaggedObject p obj)
794+ parseFromTaggedObject opts pa contentsFieldName obj pj pjl tag =
795+ (fmap L1 <$> parseFromTaggedObject opts pa contentsFieldName obj pj pjl tag) <|>
796+ (fmap R1 <$> parseFromTaggedObject opts pa contentsFieldName obj pj pjl tag)
1181797
1182−instance ( IsRecord f isRecord
1183− , FromTaggedObject' arity f isRecord
798+instance ( FromTaggedObject' arity f
1184799 , Constructor c
1185800 ) => FromTaggedObject arity (C1 c f) where
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)
801+ parseFromTaggedObject opts pa contentsFieldName obj pj pjl tag
802+ | tag == name = Just $ M1 <$> parseFromTaggedObject'
803+ opts pa contentsFieldName pj pjl obj
804+ | otherwise = Nothing
805+ where
806+ name = pack $ constructorTagModifier opts $
807+ conName (undefined :: t c f p)
1195808
1196809--------------------------------------------------------------------------------
1197810
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
811+class FromTaggedObject' arity f where
812+ parseFromTaggedObject' :: Options -> Proxy arity -> String
813+ -> (Value -> Parser a) -> (Value -> Parser [a])
814+ -> Object -> Parser (f a)
815+
816+class FromTaggedObject'' arity f isRecord where
817+ parseFromTaggedObject'' :: Options -> Proxy arity -> String
818+ -> (Value -> Parser a) -> (Value -> Parser [a])
819+ -> Object -> Tagged isRecord (Parser (f a))
820+
821+instance ( IsRecord f isRecord
822+ , FromTaggedObject'' arity f isRecord
823+ ) => FromTaggedObject' arity f where
824+ parseFromTaggedObject' opts pa contentsFieldName pj pjl =
825+ (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a)) .
826+ parseFromTaggedObject'' opts pa contentsFieldName pj pjl
827+
828+instance (FromRecord arity f) => FromTaggedObject'' arity f True where
829+ parseFromTaggedObject'' opts pa _ pj pjl =
830+ Tagged . parseRecord opts pa Nothing pj pjl
1216831
1217−instance OVERLAPPING_ FromTaggedObject' arity U1 False where
1218− -- Nullary constructors don't need a contents field
1219− parseFromTaggedObject' _ _ = Tagged (pure U1)
832+instance (GFromJSON arity f) => FromTaggedObject'' arity f False where
833+ parseFromTaggedObject'' opts pa contentsFieldName pj pjl = Tagged .
834+ (gParseJSON opts pa pj pjl <=< (.: pack contentsFieldName))
835+
836+instance OVERLAPPING_ FromTaggedObject'' arity U1 False where
837+ parseFromTaggedObject'' _ _ _ _ _ _ = Tagged (pure U1)
1220838
1221839--------------------------------------------------------------------------------
1222840
1223−-- | Constructors need to be decoded differently depending on whether they're
1224−-- a record or not. This distinction is made by 'ConsParseJSON'.
1225841class ConsFromJSON arity f where
1226− consParseJSON
1227− :: ConName :* TypeName :* Options :* FromArgs arity a
1228− -> Value -> Parser (f a)
842+ consParseJSON :: Options -> Proxy arity
843+ -> (Value -> Parser a) -> (Value -> Parser [a])
844+ -> Value -> Parser (f a)
1229845
1230846class ConsFromJSON' arity f isRecord where
1231− consParseJSON'
1232− :: ConName :* TypeName :* Options :* FromArgs arity a
1233− -> Value -> Tagged isRecord (Parser (f a))
847+ consParseJSON' :: Options -> Proxy arity
848+ -> (Maybe Text) -- ^ A dummy label
849+ -- (Nothing to use proper label)
850+ -> (Value -> Parser a) -> (Value -> Parser [a])
851+ -> Value -> Tagged isRecord (Parser (f a))
1234852
1235853instance ( IsRecord f isRecord
1236854 , ConsFromJSON' arity f isRecord
1237855 ) => ConsFromJSON arity f where
1238− consParseJSON p =
1239− (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
1240− . consParseJSON' p
1241−
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))
1248−
1249−instance RecordFromJSON arity f => ConsFromJSON' arity f True where
1250− consParseJSON' p@(cname :* tname :* _) =
1251− Tagged . withObject (showCons cname tname) (recordParseJSON (False :* p))
1252−
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)
856+ consParseJSON opts pa pj pjl v = let
857+ (v2,lab) = case (unwrapUnaryRecords opts,isUnary (undefined :: f a)) of
858+ -- use a dummy object with a dummy label
859+ (True,True) -> ((object [(pack "dummy",v)]),Just $ pack "dummy")
860+ _ ->(v,Nothing)
861+ in (unTagged :: Tagged isRecord (Parser (f a)) -> Parser (f a))
862+ $ consParseJSON' opts pa lab pj pjl v2
1265863
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
1270864
1271−instance (ProductFromJSON arity f, ProductSize f
1272− ) => ConsFromJSON' arity f False where
1273− consParseJSON' p = Tagged . productParseJSON0 p
865+instance (FromRecord arity f) => ConsFromJSON' arity f True where
866+ consParseJSON' opts pa mlab pj pjl = Tagged . (withObject "record (:*:)"
867+ $ parseRecord opts pa mlab pj pjl)
1274868
1275−--------------------------------------------------------------------------------
869+instance (GFromJSON arity f) => ConsFromJSON' arity f False where
870+ consParseJSON' opts pa _ pj pjl = Tagged . gParseJSON opts pa pj pjl
1276871
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)
872+--------------------------------------------------------------------------------
1292873
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
874+class FromRecord arity f where
875+ parseRecord :: Options -> Proxy arity
876+ -> (Maybe Text) -- ^ A dummy label
877+ -- (Nothing to use proper label)
878+ -> (Value -> Parser a) -> (Value -> Parser [a])
879+ -> Object -> Parser (f a)
880+
881+instance ( FromRecord arity a
882+ , FromRecord arity b
883+ ) => FromRecord arity (a :*: b) where
884+ parseRecord opts pa _ pj pjl obj =
885+ (:*:) <$> parseRecord opts pa Nothing pj pjl obj
886+ <*> parseRecord opts pa Nothing pj pjl obj
887+
888+instance ( Selector s
889+ , GFromJSON arity a
890+ ) => FromRecord arity (S1 s a) where
891+ parseRecord opts pa lab pj pjl =
892+ (<?> Key label) . gParseJSON opts pa pj pjl <=< (.: label)
1298893 where
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))
894+ label = fromMaybe defLabel lab
895+ defLabel = pack . fieldLabelModifier opts $
896+ selName (undefined :: t s a p)
897+
898+instance OVERLAPPING_ (Selector s, FromJSON a) =>
899+ FromRecord arity (S1 s (K1 i (Maybe a))) where
900+ parseRecord _ _ (Just lab) _ _ obj = (M1 . K1) <$> obj .:? lab
901+ parseRecord opts _ Nothing _ _ obj = (M1 . K1) <$> obj .:? pack label
902+ where
903+ label = fieldLabelModifier opts $
904+ selName (undefined :: t s (K1 i (Maybe a)) p)
1346905
1347906--------------------------------------------------------------------------------
1348907
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
908+class FromProduct arity f where
909+ parseProduct :: Options -> Proxy arity
1371910 -> Array -> Int -> Int
911+ -> (Value -> Parser a) -> (Value -> Parser [a])
1372912 -> Parser (f a)
1373913
1374−instance ( ProductFromJSON arity a
1375− , ProductFromJSON arity b
1376− ) => ProductFromJSON arity (a :*: b) where
1377− productParseJSON p arr ix len =
1378− (:*:) <$> productParseJSON p arr ix lenL
1379− <*> productParseJSON p arr ixR lenR
914+instance ( FromProduct arity a
915+ , FromProduct arity b
916+ ) => FromProduct arity (a :*: b) where
917+ parseProduct opts pa arr ix len pj pjl =
918+ (:*:) <$> parseProduct opts pa arr ix lenL pj pjl
919+ <*> parseProduct opts pa arr ixR lenR pj pjl
1380920 where
1381921 lenL = len `unsafeShiftR` 1
1382922 ixR = ix + lenL
1383923 lenR = len - lenL
1384924
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
925+instance (GFromJSON arity a) => FromProduct arity (S1 s a) where
926+ parseProduct opts pa arr ix _ pj pjl =
927+ gParseJSON opts pa pj pjl $ V.unsafeIndex arr ix
1388928
1389929--------------------------------------------------------------------------------
1390930
1391931class FromPair arity f where
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))
932+ parsePair :: Options -> Proxy arity
933+ -> (Value -> Parser a) -> (Value -> Parser [a])
934+ -> Pair -> Maybe (Parser (f a))
1396935
1397936instance ( FromPair arity a
1398937 , FromPair arity b
1399938 ) => FromPair arity (a :+: b) where
1400− parsePair p pair =
1401− (fmap L1 <$> parsePair p pair) <|>
1402− (fmap R1 <$> parsePair p pair)
939+ parsePair opts pa pj pjl pair = (fmap L1 <$> parsePair opts pa pj pjl pair) <|>
940+ (fmap R1 <$> parsePair opts pa pj pjl pair)
1403941
1404942instance ( Constructor c
943+ , GFromJSON arity a
1405944 , ConsFromJSON arity a
1406945 ) => FromPair arity (C1 c a) where
1407− parsePair (tag :* p@(_ :* opts :* _)) v
1408− | tag == tag' = Just $ M1 <$> consParseJSON (cname :* p) v
946+ parsePair opts pa pj pjl (tag, value)
947+ | tag == tag' = Just $ gParseJSON opts pa pj pjl value
1409948 | otherwise = Nothing
1410− where
1411− tag' = pack $ constructorTagModifier opts cname
1412− cname = conName (undefined :: M1 _i c _a _p)
949+ where
950+ tag' = pack $ constructorTagModifier opts $
951+ conName (undefined :: t c a p)
1413952
1414953--------------------------------------------------------------------------------
1415954
1416−class FromUntaggedValue arity f where
1417− parseUntaggedValue :: TypeName :* Options :* FromArgs arity a
1418− -> Value
1419− -> Parser (f a)
1420−
1421−instance
1422− ( FromUntaggedValue arity a
1423− , FromUntaggedValue arity b
1424− ) => FromUntaggedValue arity (a :+: b)
1425− where
1426− parseUntaggedValue p value =
1427− L1 <$> parseUntaggedValue p value <|>
1428− R1 <$> parseUntaggedValue p value
1429−
1430−instance OVERLAPPABLE_
1431− ( ConsFromJSON arity a
1432− , Constructor c
1433− ) => FromUntaggedValue arity (C1 c a)
1434− where
1435− parseUntaggedValue p = fmap M1 . consParseJSON (cname :* p)
1436− where
1437− cname = conName (undefined :: M1 _i c _f _p)
1438−
1439−instance OVERLAPPING_
1440− ( Constructor c )
1441− => FromUntaggedValue arity (C1 c U1)
1442− where
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
955+notFound :: Text -> Parser a
956+notFound key = fail $ "The key \"" ++ unpack key ++ "\" was not found"
957+{-# INLINE notFound #-}
1454958
1455959-------------------------------------------------------------------------------
1456960-- Instances
@@ -1508,20 +1012,17 @@ instance (FromJSON a, FromJSON b) => FromJSON (Either a b) where
15081012 parseJSON = parseJSON2
15091013 {-# INLINE parseJSON #-}
15101014
1511−instance FromJSON Void where
1512− parseJSON _ = fail "Cannot parse Void"
1513− {-# INLINE parseJSON #-}
1015+
15141016
15151017instance FromJSON Bool where
1516− parseJSON (Bool b) = pure b
1517− parseJSON v = typeMismatch "Bool" v
1018+ parseJSON = withBool "Bool" pure
15181019 {-# INLINE parseJSON #-}
15191020
15201021instance FromJSONKey Bool where
15211022 fromJSONKey = FromJSONKeyTextParser $ \t -> case t of
15221023 "true" -> pure True
15231024 "false" -> pure False
1524− _ -> fail $ "cannot parse key " ++ show t ++ " into Bool"
1025+ _ -> fail $ "Cannot parse key into Bool: " ++ T.unpack t
15251026
15261027instance FromJSON Ordering where
15271028 parseJSON = withText "Ordering" $ \s ->
@@ -1529,30 +1030,25 @@ instance FromJSON Ordering where
15291030 "LT" -> return LT
15301031 "EQ" -> return EQ
15311032 "GT" -> return GT
1532− _ -> fail $ "parsing Ordering failed, unexpected " ++ show s ++
1533− " (expected \"LT\", \"EQ\", or \"GT\")"
1033+ _ -> fail "Parsing Ordering value failed: expected \"LT\", \"EQ\", or \"GT\""
15341034
15351035instance FromJSON () where
15361036 parseJSON = withArray "()" $ \v ->
15371037 if V.null v
15381038 then pure ()
1539− else prependContext "()" $ fail "expected an empty array"
1039+ else fail "Expected an empty array"
15401040 {-# INLINE parseJSON #-}
15411041
15421042instance FromJSON Char where
1543− parseJSON = withText "Char" parseChar
1043+ parseJSON = withText "Char" $ \t ->
1044+ if T.compareLength t 1 == EQ
1045+ then pure $ T.head t
1046+ else fail "Expected a string of length 1"
15441047 {-# INLINE parseJSON #-}
15451048
1546− parseJSONList (String s) = pure (T.unpack s)
1547− parseJSONList v = typeMismatch "String" v
1049+ parseJSONList = withText "String" $ pure . T.unpack
15481050 {-# INLINE parseJSONList #-}
15491051
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−
15561052instance FromJSON Double where
15571053 parseJSON = parseRealFloat "Double"
15581054 {-# INLINE parseJSON #-}
@@ -1564,6 +1060,12 @@ instance FromJSONKey Double where
15641060 "-Infinity" -> pure (negate 1/0)
15651061 _ -> Scientific.toRealFloat <$> parseScientificText t
15661062
1063+instance FromJSON Number where
1064+ parseJSON (Number s) = pure $ scientificToNumber s
1065+ parseJSON Null = pure (D (0/0))
1066+ parseJSON v = typeMismatch "Number" v
1067+ {-# INLINE parseJSON #-}
1068+
15671069instance FromJSON Float where
15681070 parseJSON = parseRealFloat "Float"
15691071 {-# INLINE parseJSON #-}
@@ -1576,133 +1078,112 @@ instance FromJSONKey Float where
15761078 _ -> Scientific.toRealFloat <$> parseScientificText t
15771079
15781080instance (FromJSON a, Integral a) => FromJSON (Ratio a) where
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.
1081+ parseJSON = withObject "Rational" $ \obj ->
1082+ (%) <$> obj .: "numerator"
1083+ <*> obj .: "denominator"
1084+ {-# INLINE parseJSON #-}
1085+
1086+-- | /WARNING:/ Only parse fixed-precision numbers from trusted input
1087+-- since an attacker could easily fill up the memory of the target
1088+-- system by specifying a scientific number with a big exponent like
1089+-- @1e1000000000@.
16011090instance HasResolution a => FromJSON (Fixed a) where
1602− parseJSON = prependContext "Fixed" . withBoundedScientific' (pure . realToFrac)
1091+ parseJSON = withScientific "Fixed" $ pure . realToFrac
16031092 {-# INLINE parseJSON #-}
16041093
16051094instance FromJSON Int where
1606− parseJSON = parseBoundedIntegral "Int"
1095+ parseJSON = parseIntegral "Int"
16071096 {-# INLINE parseJSON #-}
16081097
16091098instance FromJSONKey Int where
1610− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int"
1099+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16111100
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.
1101+-- | /WARNING:/ Only parse Integers from trusted input since an
1102+-- attacker could easily fill up the memory of the target system by
1103+-- specifying a scientific number with a big exponent like
1104+-- @1e1000000000@.
16161105instance FromJSON Integer where
1617− parseJSON = parseIntegral "Integer"
1106+ parseJSON = withScientific "Integral" $ pure . truncate
16181107 {-# INLINE parseJSON #-}
16191108
16201109instance FromJSONKey Integer where
1621− fromJSONKey = FromJSONKeyTextParser $ parseIntegralText "Integer"
1110+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16221111
16231112instance FromJSON Natural where
1624− parseJSON value = do
1625− integer <- parseIntegral "Natural" value
1626− parseNatural integer
1113+ parseJSON = withScientific "Natural" $ \s ->
1114+ if Scientific.coefficient s < 0
1115+ then fail $ "Expected a Natural number but got the negative number: " <> show s
1116+ else pure $ truncate s
16271117
16281118instance FromJSONKey Natural where
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
1119+ fromJSONKey = FromJSONKeyTextParser $ \t -> parseScientificText t >>= \s ->
1120+ if Scientific.coefficient s < 0
1121+ then fail $ "Expected a Natural number but got the negative number: " <> show s
1122+ else pure $ truncate s
16391123
16401124instance FromJSON Int8 where
1641− parseJSON = parseBoundedIntegral "Int8"
1125+ parseJSON = parseIntegral "Int8"
16421126 {-# INLINE parseJSON #-}
16431127
16441128instance FromJSONKey Int8 where
1645− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int8"
1129+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16461130
16471131instance FromJSON Int16 where
1648− parseJSON = parseBoundedIntegral "Int16"
1132+ parseJSON = parseIntegral "Int16"
16491133 {-# INLINE parseJSON #-}
16501134
16511135instance FromJSONKey Int16 where
1652− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int16"
1136+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16531137
16541138instance FromJSON Int32 where
1655− parseJSON = parseBoundedIntegral "Int32"
1139+ parseJSON = parseIntegral "Int32"
16561140 {-# INLINE parseJSON #-}
16571141
16581142instance FromJSONKey Int32 where
1659− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int32"
1143+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16601144
16611145instance FromJSON Int64 where
1662− parseJSON = parseBoundedIntegral "Int64"
1146+ parseJSON = parseIntegral "Int64"
16631147 {-# INLINE parseJSON #-}
16641148
16651149instance FromJSONKey Int64 where
1666− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Int64"
1150+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16671151
16681152instance FromJSON Word where
1669− parseJSON = parseBoundedIntegral "Word"
1153+ parseJSON = parseIntegral "Word"
16701154 {-# INLINE parseJSON #-}
16711155
16721156instance FromJSONKey Word where
1673− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word"
1157+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16741158
16751159instance FromJSON Word8 where
1676− parseJSON = parseBoundedIntegral "Word8"
1160+ parseJSON = parseIntegral "Word8"
16771161 {-# INLINE parseJSON #-}
16781162
16791163instance FromJSONKey Word8 where
1680− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word8"
1164+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16811165
16821166instance FromJSON Word16 where
1683− parseJSON = parseBoundedIntegral "Word16"
1167+ parseJSON = parseIntegral "Word16"
16841168 {-# INLINE parseJSON #-}
16851169
16861170instance FromJSONKey Word16 where
1687− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word16"
1171+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16881172
16891173instance FromJSON Word32 where
1690− parseJSON = parseBoundedIntegral "Word32"
1174+ parseJSON = parseIntegral "Word32"
16911175 {-# INLINE parseJSON #-}
16921176
16931177instance FromJSONKey Word32 where
1694− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word32"
1178+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
16951179
16961180instance FromJSON Word64 where
1697− parseJSON = parseBoundedIntegral "Word64"
1181+ parseJSON = parseIntegral "Word64"
16981182 {-# INLINE parseJSON #-}
16991183
17001184instance FromJSONKey Word64 where
1701− fromJSONKey = FromJSONKeyTextParser $ parseBoundedIntegralText "Word64"
1185+ fromJSONKey = FromJSONKeyTextParser parseIntegralText
17021186
1703−instance FromJSON CTime where
1704− parseJSON = fmap CTime . parseJSON
1705− {-# INLINE parseJSON #-}
17061187
17071188instance FromJSON Text where
17081189 parseJSON = withText "Text" pure
@@ -1732,17 +1213,17 @@ parseVersionText = go . readP_to_S parseVersion . unpack
17321213 where
17331214 go [(v,[])] = return v
17341215 go (_ : xs) = go xs
1735− go _ = fail "parsing Version failed"
1216+ go _ = fail $ "could not parse Version"
17361217
17371218-------------------------------------------------------------------------------
17381219-- semigroups NonEmpty
17391220-------------------------------------------------------------------------------
17401221
17411222instance FromJSON1 NonEmpty where
1742− liftParseJSON p _ = withArray "NonEmpty" $
1223+ liftParseJSON p _ = withArray "NonEmpty a" $
17431224 (>>= ne) . Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
17441225 where
1745− ne [] = fail "parsing NonEmpty failed, unexpected empty list"
1226+ ne [] = fail "Expected a NonEmpty but got an empty list"
17461227 ne (x:xs) = pure (x :| xs)
17471228 {-# INLINE liftParseJSON #-}
17481229
@@ -1763,7 +1244,7 @@ instance FromJSON Scientific where
17631244-------------------------------------------------------------------------------
17641245
17651246instance FromJSON1 DList.DList where
1766− liftParseJSON p _ = withArray "DList" $
1247+ liftParseJSON p _ = withArray "DList a" $
17671248 fmap DList.fromList .
17681249 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
17691250 {-# INLINE liftParseJSON #-}
@@ -1790,7 +1271,7 @@ instance (FromJSON a) => FromJSON (Identity a) where
17901271 parseJSONList = liftParseJSONList parseJSON parseJSONList
17911272 {-# INLINE parseJSONList #-}
17921273
1793−instance (FromJSONKey a) => FromJSONKey (Identity a) where
1274+instance (FromJSONKey a, FromJSON a) => FromJSONKey (Identity a) where
17941275 fromJSONKey = coerceFromJSONKeyFunction (fromJSONKey :: FromJSONKeyFunction a)
17951276 fromJSONKeyList = coerceFromJSONKeyFunction (fromJSONKeyList :: FromJSONKeyFunction [a])
17961277
@@ -1840,7 +1321,7 @@ instance (FromJSON1 f, FromJSON1 g) => FromJSON1 (Sum f g) where
18401321 inr = "InR"
18411322
18421323 liftParseJSON _ _ _ = fail $
1843− "parsing Sum failed, expected an object with a single property " ++
1324+ "expected an object with a single property " ++
18441325 "where the property key should be either " ++
18451326 "\"InL\" or \"InR\""
18461327 {-# INLINE liftParseJSON #-}
@@ -1854,7 +1335,7 @@ instance (FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum f g a) where
18541335-------------------------------------------------------------------------------
18551336
18561337instance FromJSON1 Seq.Seq where
1857− liftParseJSON p _ = withArray "Seq" $
1338+ liftParseJSON p _ = withArray "Seq a" $
18581339 fmap Seq.fromList .
18591340 Tr.sequence . zipWith (parseIndexedJSON p) [0..] . V.toList
18601341 {-# INLINE liftParseJSON #-}
@@ -1888,15 +1369,15 @@ instance FromJSON a => FromJSON (IntMap.IntMap a) where
18881369
18891370instance (FromJSONKey k, Ord k) => FromJSON1 (M.Map k) where
18901371 liftParseJSON p _ = case fromJSONKey of
1891− FromJSONKeyCoerce _ -> withObject "Map" $
1372+ FromJSONKeyCoerce _-> withObject "Map k v" $
18921373 fmap (H.foldrWithKey (M.insert . unsafeCoerce) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1893− FromJSONKeyText f -> withObject "Map" $
1374+ FromJSONKeyText f -> withObject "Map k v" $
18941375 fmap (H.foldrWithKey (M.insert . f) M.empty) . H.traverseWithKey (\k v -> p v <?> Key k)
1895− FromJSONKeyTextParser f -> withObject "Map" $
1376+ FromJSONKeyTextParser f -> withObject "Map k v" $
18961377 H.foldrWithKey (\k v m -> M.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure M.empty)
1897− FromJSONKeyValue f -> withArray "Map" $ \arr ->
1898− fmap M.fromList . Tr.sequence .
1899− zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
1378+ FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1379+ M.fromList <$> (Tr.sequence .
1380+ zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr)
19001381 {-# INLINE liftParseJSON #-}
19011382
19021383instance (FromJSONKey k, Ord k, FromJSON v) => FromJSON (M.Map k v) where
@@ -1916,24 +1397,12 @@ instance (FromJSON v) => FromJSON (Tree.Tree v) where
19161397 parseJSON = parseJSON1
19171398 {-# INLINE parseJSON #-}
19181399
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−
19311400-------------------------------------------------------------------------------
19321401-- vector
19331402-------------------------------------------------------------------------------
19341403
19351404instance FromJSON1 Vector where
1936− liftParseJSON p _ = withArray "Vector" $
1405+ liftParseJSON p _ = withArray "Vector a" $
19371406 V.mapM (uncurry $ parseIndexedJSON p) . V.indexed
19381407 {-# INLINE liftParseJSON #-}
19391408
@@ -1947,14 +1416,14 @@ vectorParseJSON s = withArray s $ fmap V.convert . V.mapM (uncurry $ parseIndexe
19471416{-# INLINE vectorParseJSON #-}
19481417
19491418instance (Storable a, FromJSON a) => FromJSON (VS.Vector a) where
1950− parseJSON = vectorParseJSON "Data.Vector.Storable.Vector"
1419+ parseJSON = vectorParseJSON "Data.Vector.Storable.Vector a"
19511420
19521421instance (VP.Prim a, FromJSON a) => FromJSON (VP.Vector a) where
1953− parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector"
1422+ parseJSON = vectorParseJSON "Data.Vector.Primitive.Vector a"
19541423 {-# INLINE parseJSON #-}
19551424
19561425instance (VG.Vector VU.Vector a, FromJSON a) => FromJSON (VU.Vector a) where
1957− parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector"
1426+ parseJSON = vectorParseJSON "Data.Vector.Unboxed.Vector a"
19581427 {-# INLINE parseJSON #-}
19591428
19601429-------------------------------------------------------------------------------
@@ -1968,15 +1437,15 @@ instance (Eq a, Hashable a, FromJSON a) => FromJSON (HashSet.HashSet a) where
19681437
19691438instance (FromJSONKey k, Eq k, Hashable k) => FromJSON1 (H.HashMap k) where
19701439 liftParseJSON p _ = case fromJSONKey of
1971− FromJSONKeyCoerce _ -> withObject "HashMap ~Text" $
1440+ FromJSONKeyCoerce _ -> withObject "HashMap ~Text v" $
19721441 uc . H.traverseWithKey (\k v -> p v <?> Key k)
1973− FromJSONKeyText f -> withObject "HashMap" $
1442+ FromJSONKeyText f -> withObject "HashMap k v" $
19741443 fmap (mapKey f) . H.traverseWithKey (\k v -> p v <?> Key k)
1975− FromJSONKeyTextParser f -> withObject "HashMap" $
1444+ FromJSONKeyTextParser f -> withObject "HashMap k v" $
19761445 H.foldrWithKey (\k v m -> H.insert <$> f k <?> Key k <*> p v <?> Key k <*> m) (pure H.empty)
1977− FromJSONKeyValue f -> withArray "Map" $ \arr ->
1978− fmap H.fromList . Tr.sequence .
1979− zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr
1446+ FromJSONKeyValue f -> withArray "Map k v" $ \arr ->
1447+ H.fromList <$> (Tr.sequence .
1448+ zipWith (parseIndexedJSONPair f p) [0..] . V.toList $ arr)
19801449 where
19811450 uc :: Parser (H.HashMap Text v) -> Parser (H.HashMap k v)
19821451 uc = unsafeCoerce
@@ -1997,33 +1466,11 @@ instance FromJSON DotNetTime where
19971466 parseJSON = withText "DotNetTime" $ \t ->
19981467 let (s,m) = T.splitAt (T.length t - 5) t
19991468 t' = T.concat [s,".",m]
2000− in case parseTimeM True defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
1469+ in case parseTime defaultTimeLocale "/Date(%s%Q)/" (unpack t') of
20011470 Just d -> pure (DotNetTime d)
20021471 _ -> fail "could not parse .NET time"
20031472 {-# INLINE parseJSON #-}
20041473
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−
20271474-------------------------------------------------------------------------------
20281475-- time
20291476-------------------------------------------------------------------------------
@@ -2049,17 +1496,6 @@ instance FromJSONKey LocalTime where
20491496 fromJSONKey = FromJSONKeyTextParser (Time.run Time.localTime)
20501497
20511498
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.
20631499instance FromJSON ZonedTime where
20641500 parseJSON = withText "ZonedTime" (Time.run Time.zonedTime)
20651501
@@ -2074,168 +1510,41 @@ instance FromJSONKey UTCTime where
20741510 fromJSONKey = FromJSONKeyTextParser (Time.run Time.utcTime)
20751511
20761512
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.
1513+-- | /WARNING:/ Only parse lengths of time from trusted input
1514+-- since an attacker could easily fill up the memory of the target
1515+-- system by specifying a scientific number with a big exponent like
1516+-- @1e1000000000@.
20811517instance FromJSON NominalDiffTime where
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
1518+ parseJSON = withScientific "NominalDiffTime" $ pure . realToFrac
20921519 {-# INLINE parseJSON #-}
20931520
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− <$> obj .: "months"
2109− <*> obj .: "days"
2110−
2111−instance FromJSON DayOfWeek where
2112− parseJSON = withText "DaysOfWeek" parseDayOfWeek
2113−
2114−parseDayOfWeek :: T.Text -> Parser DayOfWeek
2115−parseDayOfWeek t = case T.toLower t of
2116− "monday" -> return Monday
2117− "tuesday" -> return Tuesday
2118− "wednesday" -> return Wednesday
2119− "thursday" -> return Thursday
2120− "friday" -> return Friday
2121− "saturday" -> return Saturday
2122− "sunday" -> return Sunday
2123− _ -> fail "Invalid week day"
2124−
2125−instance FromJSONKey DayOfWeek where
2126− fromJSONKey = FromJSONKeyTextParser parseDayOfWeek
2127−
21281521-------------------------------------------------------------------------------
21291522-- base Monoid/Semigroup
21301523-------------------------------------------------------------------------------
21311524
2132−instance FromJSON1 Monoid.Dual where
2133− liftParseJSON p _ = fmap Monoid.Dual . p
2134− {-# INLINE liftParseJSON #-}
2135−
2136−instance FromJSON a => FromJSON (Monoid.Dual a) where
2137− parseJSON = parseJSON1
2138− {-# INLINE parseJSON #-}
2139−
2140−
2141−instance FromJSON1 Monoid.First where
2142− liftParseJSON p p' = fmap Monoid.First . liftParseJSON p p'
2143− {-# INLINE liftParseJSON #-}
2144−
2145−instance FromJSON a => FromJSON (Monoid.First a) where
2146− parseJSON = parseJSON1
2147− {-# INLINE parseJSON #-}
2148−
2149−
2150−instance FromJSON1 Monoid.Last where
2151− liftParseJSON p p' = fmap Monoid.Last . liftParseJSON p p'
2152− {-# INLINE liftParseJSON #-}
2153−
2154−instance FromJSON a => FromJSON (Monoid.Last a) where
2155− parseJSON = parseJSON1
2156− {-# INLINE parseJSON #-}
2157−
2158−
2159−instance FromJSON1 Semigroup.Min where
2160− liftParseJSON p _ a = Semigroup.Min <$> p a
1525+instance FromJSON1 Dual where
1526+ liftParseJSON p _ = fmap Dual . p
21611527 {-# INLINE liftParseJSON #-}
21621528
2163− liftParseJSONList _ p a = fmap Semigroup.Min <$> p a
2164− {-# INLINE liftParseJSONList #-}
2165−
2166−instance (FromJSON a) => FromJSON (Semigroup.Min a) where
1529+instance FromJSON a => FromJSON (Dual a) where
21671530 parseJSON = parseJSON1
21681531 {-# INLINE parseJSON #-}
21691532
2170− parseJSONList = liftParseJSONList parseJSON parseJSONList
2171− {-# INLINE parseJSONList #-}
21721533
2173−
2174−instance FromJSON1 Semigroup.Max where
2175− liftParseJSON p _ a = Semigroup.Max <$> p a
1534+instance FromJSON1 First where
1535+ liftParseJSON p p' = fmap First . liftParseJSON p p'
21761536 {-# INLINE liftParseJSON #-}
21771537
2178− liftParseJSONList _ p a = fmap Semigroup.Max <$> p a
2179− {-# INLINE liftParseJSONList #-}
2180−
2181−instance (FromJSON a) => FromJSON (Semigroup.Max a) where
1538+instance FromJSON a => FromJSON (First a) where
21821539 parseJSON = parseJSON1
21831540 {-# INLINE parseJSON #-}
21841541
2185− parseJSONList = liftParseJSONList parseJSON parseJSONList
2186− {-# INLINE parseJSONList #-}
2187−
21881542
2189−instance FromJSON1 Semigroup.First where
2190− liftParseJSON p _ a = Semigroup.First <$> p a
1543+instance FromJSON1 Last where
1544+ liftParseJSON p p' = fmap Last . liftParseJSON p p'
21911545 {-# INLINE liftParseJSON #-}
21921546
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
1547+instance FromJSON a => FromJSON (Last a) where
22391548 parseJSON = parseJSON1
22401549 {-# INLINE parseJSON #-}
22411550
@@ -2243,21 +1552,11 @@ instance FromJSON a => FromJSON (Semigroup.Option a) where
22431552-- tagged
22441553-------------------------------------------------------------------------------
22451554
2246−instance FromJSON1 Proxy where
2247− {-# INLINE liftParseJSON #-}
2248− liftParseJSON _ _ = fromNull "Proxy" Proxy
2249−
22501555instance FromJSON (Proxy a) where
22511556 {-# INLINE parseJSON #-}
2252− parseJSON = fromNull "Proxy" Proxy
1557+ parseJSON Null = pure Proxy
1558+ parseJSON v = typeMismatch "Proxy" v
22531559
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 #-}
22611560
22621561instance FromJSON1 (Tagged a) where
22631562 liftParseJSON p _ = fmap Tagged . p
@@ -2280,7 +1579,10 @@ instance (FromJSON a, FromJSON b, FromJSON c) => FromJSONKey (a,b,c)
22801579instance (FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSONKey (a,b,c,d)
22811580
22821581instance FromJSONKey Char where
2283− fromJSONKey = FromJSONKeyTextParser parseChar
1582+ fromJSONKey = FromJSONKeyTextParser $ \t ->
1583+ if T.length t == 1
1584+ then return (T.index t 0)
1585+ else typeMismatch "Expected Char but String didn't contain exactly one character" (String t)
22841586 fromJSONKeyList = FromJSONKeyText T.unpack
22851587
22861588instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where
@@ -2290,7 +1592,7 @@ instance (FromJSONKey a, FromJSON a) => FromJSONKey [a] where
22901592-- Tuple instances, see tuple-instances-from.hs
22911593-------------------------------------------------------------------------------
22921594
2293−instance FromJSON2 (,) where
1595+instance FromJSON2 ((,) ) where
22941596 liftParseJSON2 pA _ pB _ = withArray "(a, b)" $ \t ->
22951597 let n = V.length t
22961598 in if n == 2