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 !(Chunks Member)

Array !(Chunks Value)

String !ShortText

Number !Scientific

Null

True

False

Instances

Eq Value

Defined in Json

Methods

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

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

Show Value

Defined in Json

Methods

showsPrec :: Int -> Value -> ShowS

show :: Value -> String

showList :: [Value] -> ShowS

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

Eq Member

Defined in Json

Methods

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

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

Show Member

Defined in Json

Methods

showsPrec :: Int -> Member -> ShowS

show :: Member -> String

showList :: [Member] -> ShowS

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

Instances

Eq SyntaxException

Defined in Json

Methods

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

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

Show SyntaxException

Defined in Json

Methods

showsPrec :: Int -> SyntaxException -> ShowS

show :: SyntaxException -> String

showList :: [SyntaxException] -> ShowS

Exception SyntaxException

Defined in Json

Methods

toException :: SyntaxException -> SomeException

fromException :: SomeException -> Maybe SyntaxException

displayException :: SyntaxException -> String

Functions

decode :: Bytes -> Either SyntaxException Value

Decode a JSON syntax tree from a byte sequence.

encode :: Value -> Builder