Json.Token

Documentation

data Token

A token in a JSON document.

Constructors

LeftBrace

RightBrace

LeftBracket

RightBracket

Comma

Colon

BooleanTrue

BooleanFalse

Null

String !ShortText

Number !Scientific

Instances

Eq Token

Defined in Json.Token

Methods

(==) :: Token -> Token -> Bool

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

Show Token

Defined in Json.Token

Methods

showsPrec :: Int -> Token -> ShowS

show :: Token -> String

showList :: [Token] -> ShowS

data TokenException

An exception encountered while tokenizing a JSON document.

Constructors

InvalidNumber

InvalidLeader

ExpectedTrue

ExpectedFalse

ExpectedNull

LeadingZero

InvalidEscapeSequence

IncompleteString

IncompleteEscapeSequence

Instances

Eq TokenException

Defined in Json.Token

Methods

(==) :: TokenException -> TokenException -> Bool

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

Show TokenException

Defined in Json.Token

Methods

showsPrec :: Int -> TokenException -> ShowS

show :: TokenException -> String

showList :: [TokenException] -> ShowS

decode :: Bytes -> Either TokenException (SmallArray Token)

Decode a sequence as JSON tokens. This allows token sequences that would be rejected by the ABNF given in RFC 7159:

>>> decode (Bytes.fromAsciiString "[ , true }")
Right [ LeftBracket, Comma, BooleanTrue, RightBrace ]

It is up to the user to reject such malformed JSON when they parse the token sequence. More surprisingly, this tokenizer accepts some unnatural juxtapositions of token sequences without whitespace. For example:

>>> decode (Bytes.fromAsciiString "55truefalse")
Right [ Number 55, BooleanTrue, BooleanFalse ]
>>> decode (Bytes.fromAsciiString "null\"hello\"")
Right [ Null, String "hello" ]

Acceptance of such samples simplifies the implementation of this tokenizer. These unnatural juxtapositions always result in token sequences that should be rejected anyway in the subsequent parsing done by the user. Consequently, their acceptance is not considered harmful.