Safe Haskell	None
Language	GHC2024

Circuit.Parser.Csv.Lexer

Contents

Tokens
Running

Description

Fast imperative CSV tokenizer over strict ByteString.

Complementary to the combinator path in Circuit.Parser.Csv: a single unsafeIndex pass emitting zero-copy slices. Commas are implied between adjacent field tokens; CRowEnd marks record boundaries. CQuoted payloads keep their doubled-quote escapes intact.

Synopsis

data CsvToken
- = CField ByteString
- | CQuoted ByteString
- | CRowEnd
runCsvLexerBS :: ByteString -> Either (Int, String) [CsvToken]

Tokens

data CsvToken Source #

A flat CSV token. Payloads are zero-copy slices of the input.

Constructors

CField ByteString
CQuoted ByteString
CRowEnd

Instances

Instances details

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

Running

runCsvLexerBS :: ByteString -> Either (Int, String) [CsvToken] Source #

Tokenize a strict ByteString as CSV.

On failure, returns the byte offset and a message.

>>> runCsvLexerBS (C.pack "a,b\r\n\"x\"\"y\",z")
Right [CField "a",CField "b",CRowEnd,CQuoted "x\"\"y",CField "z"]

>>> runCsvLexerBS (C.pack "a,\"b")
Left (4,"unterminated quoted field")

>>> runCsvLexerBS (C.pack "ab\"cd")
Left (2,"unexpected quote in plain field")