Json

Types

data Value

The JSON syntax tree described by the ABNF in RFC 7159. Notable design decisions include:

• True and False are their own data constructors rather than being lumped together under a data constructor for boolean values. This improves performance when decoding the syntax tree to a Bool.
• Object uses an association list rather than a hash map. This is the data type that key-value pairs can be parsed into most cheaply.
• Object and Array both use Chunks rather than using SmallArray or cons-list directly. This a middle ground between those two types. We get the efficent use of cache lines that SmallArray offers, and we get the worst-case O(1) appends that cons-list offers. Users will typically fold over the elements with the Foldable instance of Chunks, although there are functions in Data.Chunks that efficently perform other operations.

Constructors

Object !(SmallArray Member)

Array !(SmallArray Value)

String !ShortText

Number !Scientific

Null

True

False

Instances

Show Value

Defined in Json

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

Eq Value

Defined in Json

Methods

(==) :: Value -> Value -> Bool

(/=) :: Value -> Value -> Bool

ToValue Value

Defined in Json

Methods

toValue :: Value -> Value

data Member

A key-value pair in a JSON object. The name of this type is taken from section 4 of RFC 7159.

Constructors

Member

Fields

• key :: !ShortText
• value :: !Value

Instances

Show Member

Defined in Json

Methods

showsPrec :: Int -> Member -> ShowS

show :: Member -> String

showList :: [Member] -> ShowS

Eq Member

Defined in Json

Methods

(==) :: Member -> Member -> Bool

(/=) :: Member -> Member -> Bool

data SyntaxException

Exceptions that can happen while parsing JSON. Do not pattern match on values of this type. New data constructors may be added at any time without a major version bump.

Constructors

EmptyInput

ExpectedColon

ExpectedCommaOrRightBracket

ExpectedFalse

ExpectedNull

ExpectedQuote

ExpectedQuoteOrRightBrace

ExpectedTrue

IncompleteArray

IncompleteEscapeSequence

IncompleteObject

IncompleteString

InvalidEscapeSequence

InvalidLeader

InvalidNumber

LeadingZero

UnexpectedLeftovers

PossibleOverflow

Instances

Exception SyntaxException

Defined in Json

Methods

toException :: SyntaxException -> SomeException

fromException :: SomeException -> Maybe SyntaxException

displayException :: SyntaxException -> String

Show SyntaxException

Defined in Json

Methods

showsPrec :: Int -> SyntaxException -> ShowS

show :: SyntaxException -> String

showList :: [SyntaxException] -> ShowS

Eq SyntaxException

Defined in Json

Methods

(==) :: SyntaxException -> SyntaxException -> Bool

(/=) :: SyntaxException -> SyntaxException -> Bool

Classes

class ToValue a where

Typeclass for types that can be encoded as JSON.

Methods

toValue :: a -> Value

Instances

ToValue Int16

Defined in Json

Methods

toValue :: Int16 -> Value

ToValue Int32

Defined in Json

Methods

toValue :: Int32 -> Value

ToValue Int64

Defined in Json

Methods

toValue :: Int64 -> Value

ToValue Int8

Defined in Json

Methods

toValue :: Int8 -> Value

ToValue Word16

Defined in Json

Methods

toValue :: Word16 -> Value

ToValue Word32

Defined in Json

Methods

toValue :: Word32 -> Value

ToValue Word64

Defined in Json

Methods

toValue :: Word64 -> Value

ToValue Word8

Defined in Json

Methods

toValue :: Word8 -> Value

ToValue Value

Defined in Json

Methods

toValue :: Value -> Value

ToValue Scientific

Defined in Json

Methods

toValue :: Scientific -> Value

ToValue Text

Defined in Json

Methods

toValue :: Text -> Value

ToValue ShortText

Defined in Json

Methods

toValue :: ShortText -> Value

ToValue ()

Encodes the unit value as JSON null.

Defined in Json

Methods

toValue :: () -> Value

ToValue Bool

Defined in Json

Methods

toValue :: Bool -> Value

ToValue Int

Defined in Json

Methods

toValue :: Int -> Value

ToValue Word

Defined in Json

Methods

toValue :: Word -> Value

ToValue a => ToValue (Array a)

Defined in Json

Methods

toValue :: Array a -> Value

(Prim a, ToValue a) => ToValue (PrimArray a)

Defined in Json

Methods

toValue :: PrimArray a -> Value

ToValue a => ToValue (SmallArray a)

Defined in Json

Methods

toValue :: SmallArray a -> Value

ToValue a => ToValue [a]

Defined in Json

Methods

toValue :: [a] -> Value

Functions

decode :: Bytes -> Either SyntaxException Value

Decode a JSON syntax tree from a byte sequence.

decodeNewlineDelimited :: Bytes -> Either SyntaxException (SmallArray Value)

Decode newline-delimited JSON. Both the LF and the CRLF conventions are supported. The newline character (or character sequence) following the final object may be omitted. This also allows blanks lines consisting of only whitespace.

It's not strictly necessary for this to be a part of this library, but newline-delimited JSON is somewhat common in practice. It's nice to have this here instead of having to reimplement it in a bunch of different applications.

Note: To protect against malicious input, this reject byte sequences with more than 10 million newlines. If this is causing a problem for you, open an issue.

Other note: in the future, this function might be changed transparently to parallelize the decoding of large input (at least 1000 lines) with GHC sparks.

encode :: Value -> Builder

Encode a JSON syntax tree.

toChunks :: Value -> Chunks

toShortText :: Value -> ShortText

toText :: Value -> Text

toBytes :: Value -> Bytes

toByteArray :: Value -> ByteArray

Infix Synonyms

pattern (:->) :: ShortText -> Value -> Member

Infix pattern synonym for Member.

Constants

emptyArray :: Value

An array with no elements (i.e. [])

emptyObject :: Value

An object with no members (i.e. {})

Value Construction

int :: Int -> Value

int8 :: Int8 -> Value

int16 :: Int16 -> Value

int32 :: Int32 -> Value

int64 :: Int64 -> Value

word8 :: Word8 -> Value

word16 :: Word16 -> Value

word32 :: Word32 -> Value

word64 :: Word64 -> Value

bool :: Bool -> Value

text :: Text -> Value

shortText :: ShortText -> Value

Array Construction

arrayFromList :: [Value] -> Value

Construct a JSON array from a list of JSON values.

Unlike objectFromList, this is not currently equipped with a rewrite rule.

Object Construction

objectFromList :: [Member] -> Value

Construct a JSON object from a list of members.

Note: When the argument is a list literal with 16 or fewer elements, a rewrite rule transforms this into the appropriate objectN function. When the argument is not a list literal, this function just calls smallArrayFromList on the members, which has poor performance.

object1 :: Member -> Value

Construct a JSON object with one member.

object2 :: Member -> Member -> Value

Construct a JSON object with two members.

object3 :: Member -> Member -> Member -> Value

Construct a JSON object with three members.

object4 :: Member -> Member -> Member -> Member -> Value

Construct a JSON object with four members.

object5 :: Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with five members.

object6 :: Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with six members.

object7 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with seven members.

object8 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with nine members.

object9 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with nine members.

object10 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with ten members.

object11 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with eleven members.

object12 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with twelve members.

object13 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with thirteen members.

object14 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with fourteen members.

object15 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with fifteen members.

object16 :: Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Member -> Value

Construct a JSON object with sixteen members.