Safe Haskell	None
Language	GHC2024

Circuit.Parser.Json.Lexer

Contents

Tokens
Running

Description

Fast imperative JSON tokenizer over strict ByteString.

Complementary to the combinator path in Circuit.Parser.Json: it trades compositionality for raw speed — a single unsafeIndex pass emitting zero-copy slices. Structural tokens only; validation (number grammar, escape legality, nesting) belongs to the layer above.

Synopsis

data JsonToken
- = TBraceOpen
- | TBraceClose
- | TBrackOpen
- | TBrackClose
- | TComma
- | TColon
- | TString ByteString
- | TNumber ByteString
- | TTrue
- | TFalse
- | TNull
runJsonLexerBS :: ByteString -> Either (Int, String) [JsonToken]

Tokens

data JsonToken Source #

A flat JSON structural token. TString and TNumber payloads are zero-copy slices of the input; a TString keeps its escapes intact.

Constructors

TBraceOpen
TBraceClose
TBrackOpen
TBrackClose
TComma
TColon
TString ByteString
TNumber ByteString
TTrue
TFalse
TNull

Instances

Instances details

Eq JsonToken Source #
Instance details Defined in Circuit.Parser.Json.Lexer Methods (==) :: JsonToken -> JsonToken -> Bool # (/=) :: JsonToken -> JsonToken -> Bool #
Show JsonToken Source #
Instance details Defined in Circuit.Parser.Json.Lexer Methods showsPrec :: Int -> JsonToken -> ShowS # show :: JsonToken -> String # showList :: [JsonToken] -> ShowS #

Running

runJsonLexerBS :: ByteString -> Either (Int, String) [JsonToken] Source #

Tokenize a strict ByteString.

On failure, returns the byte offset and a message.

>>> runJsonLexerBS (C.pack "{\"a\": [1, true]}")
Right [TBraceOpen,TString "a",TColon,TBrackOpen,TNumber "1",TComma,TTrue,TBrackClose,TBraceClose]

>>> runJsonLexerBS (C.pack "[1")
Right [TBrackOpen,TNumber "1"]

>>> runJsonLexerBS (C.pack "\"ab")
Left (3,"unterminated string")

>>> runJsonLexerBS (C.pack "nul")
Left (0,"bad literal")

>>> runJsonLexerBS (C.pack "@")
Left (0,"unexpected byte 64")