| Copyright | (c) Dong Han 2017-2019 |
|---|---|
| License | BSD |
| Maintainer | winterland1989@gmail.com |
| Stability | experimental |
| Portability | non-portable |
| Safe Haskell | None |
| Language | Haskell2010 |
Std.Data.Parser.Base
Description
This module provide a simple resumable Parser, which is suitable for binary protocol and simple textual protocol parsing.
You can use Alternative instance to do backtracking, each branch will either succeed and may consume some input, or fail without consume anything. It's recommend to use peek to avoid backtracking if possible to get high performance.
Synopsis
- data Result a
- type ParseStep r = Bytes -> Result r
- newtype Parser a = Parser {}
- parse :: Parser a -> Bytes -> Either String a
- parse' :: Parser a -> Bytes -> (Bytes, Either String a)
- parseChunk :: Parser a -> Bytes -> Result a
- parseChunks :: Monad m => m Bytes -> Parser a -> Bytes -> m (Bytes, Either String a)
- finishParsing :: Result a -> (Bytes, Either String a)
- runAndKeepTrack :: Parser a -> Parser (Result a, [Bytes])
- ensureN :: Int -> Parser ()
- endOfInput :: Parser Bool
- decodePrim :: forall a. UnalignedAccess a => Parser a
- decodePrimLE :: forall a. UnalignedAccess (LE a) => Parser a
- decodePrimBE :: forall a. UnalignedAccess (BE a) => Parser a
- scan :: s -> (s -> Word8 -> Maybe s) -> Parser Bytes
- scanChunks :: s -> (s -> Bytes -> Either s (Bytes, Bytes)) -> Parser Bytes
- peekMaybe :: Parser (Maybe Word8)
- peek :: Parser Word8
- satisfy :: (Word8 -> Bool) -> Parser Word8
- satisfyWith :: (Word8 -> a) -> (a -> Bool) -> Parser a
- word8 :: Word8 -> Parser ()
- char8 :: Char -> Parser ()
- anyWord8 :: Parser Word8
- endOfLine :: Parser ()
- skip :: Int -> Parser ()
- skipWhile :: (Word8 -> Bool) -> Parser ()
- skipSpaces :: Parser ()
- take :: Int -> Parser Bytes
- takeTill :: (Word8 -> Bool) -> Parser Bytes
- takeWhile :: (Word8 -> Bool) -> Parser Bytes
- takeWhile1 :: (Word8 -> Bool) -> Parser Bytes
- bytes :: Bytes -> Parser ()
- bytesCI :: Bytes -> Parser ()
- text :: Text -> Parser ()
Parser types
Simple parsing result, that represent respectively:
- success: the remaining unparsed data and the parsed value
- failure: the remaining unparsed data and the error message
- partial: that need for more input data, supply empty bytes to indicate
endOfInput
Simple CPSed parser
Running a parser
parse' :: Parser a -> Bytes -> (Bytes, Either String a) Source #
Parse the complete input, without resupplying, return the rest bytes
parseChunks :: Monad m => m Bytes -> Parser a -> Bytes -> m (Bytes, Either String a) Source #
Run a parser with an initial input string, and a monadic action that can supply more input if needed.
Note, once the monadic action return empty bytes, parsers will stop drawing
more bytes (take it as endOfInput).
finishParsing :: Result a -> (Bytes, Either String a) Source #
Finish parsing and fetch result, feed empty bytes if it's Partial result.
Basic parsers
ensureN :: Int -> Parser () Source #
Ensure that there are at least n bytes available. If not, the
computation will escape with Partial.
endOfInput :: Parser Bool Source #
Test whether all input has been consumed, i.e. there are no remaining undecoded bytes.
Primitive decoders
decodePrim :: forall a. UnalignedAccess a => Parser a Source #
decodePrimLE :: forall a. UnalignedAccess (LE a) => Parser a Source #
decodePrimBE :: forall a. UnalignedAccess (BE a) => Parser a Source #
More parsers
scan :: s -> (s -> Word8 -> Maybe s) -> Parser Bytes Source #
A stateful scanner. The predicate consumes and transforms a
state argument, and each transformed state is passed to successive
invocations of the predicate on each byte of the input until one
returns Nothing or the input ends.
This parser does not fail. It will return an empty string if the
predicate returns Nothing on the first byte of input.
peekMaybe :: Parser (Maybe Word8) Source #
Match any byte, to perform lookahead. Returns Nothing if end of
input has been reached. Does not consume any input.
Match any byte, to perform lookahead. Does not consume any input, but will fail if end of input has been reached.
satisfy :: (Word8 -> Bool) -> Parser Word8 Source #
The parser satisfy p succeeds for any byte for which the
predicate p returns True. Returns the byte that is actually
parsed.
digit = satisfy isDigit
where isDigit w = w >= 48 && w <= 57satisfyWith :: (Word8 -> a) -> (a -> Bool) -> Parser a Source #
The parser satisfyWith f p transforms a byte, and succeeds if
the predicate p returns True on the transformed value. The
parser returns the transformed byte that was parsed.
endOfLine :: Parser () Source #
Match either a single newline byte '\n', or a carriage
return followed by a newline byte "\r\n".
skipWhile :: (Word8 -> Bool) -> Parser () Source #
Skip past input for as long as the predicate returns True.
skipSpaces :: Parser () Source #
Skip over white space using isSpace.
takeTill :: (Word8 -> Bool) -> Parser Bytes Source #
Consume input as long as the predicate returns False or reach the end of input,
and return the consumed input.
takeWhile :: (Word8 -> Bool) -> Parser Bytes Source #
Consume input as long as the predicate returns True or reach the end of input,
and return the consumed input.