Portability | portable to Hugs and GHC. |
---|---|

Stability | experimental |

Maintainer | Adam Langley <agl@imperialviolet.org> |

This is a version of the Get monad for incremental parsing. The parser is written as if a single, huge, strict ByteString was to be parsed. It produces results as it parses by calling yield.

However, if the parser runs out of data, rather than failing the caller sees a Partial result, which includes the list of yielded values so far and a continuation. By calling the continuation with more data, the parser continues, none the wiser.

Take the following example

testParse = do a <- getWord16be b <- getWord16be return $ a + b test = runGet testParse $ B.pack [1,0,0]

Here `testParse`

needs to read 4 bytes in order to complete, so test is
a Partial, which includes the continuation function, so which you can pass
more data until it completes

The lookahead functions have been removed from this parser because of their incompatibility with the incremental monad at the moment.

- data Get r a
- data Result a
- = Failed String
- | Finished ByteString a
- | Partial (ByteString -> Result a)

- runGet :: Get r r -> ByteString -> Result r
- skip :: Int -> Get r ()
- bytesRead :: Get r Int
- remaining :: Get r Int
- isEmpty :: Get r Bool
- plus :: Get r a -> Get r a -> Get r a
- zero :: Get r a
- spanOf :: (Word8 -> Bool) -> Get r ByteString
- suspend :: Get r ()
- getWord8 :: Get r Word8
- getByteString :: Int -> Get r ByteString
- getWord16be :: Get r Word16
- getWord32be :: Get r Word32
- getWord64be :: Get r Word64
- getWord16le :: Get r Word16
- getWord32le :: Get r Word32
- getWord64le :: Get r Word64
- getWordhost :: Get r Word
- getWord16host :: Get r Word16
- getWord32host :: Get r Word32
- getWord64host :: Get r Word64

# The Get type

Monad (Get r) | |

Functor (Get r) | |

MonadPlus (Get r) | |

Applicative (Get r) | |

Alternative (Get r) | |

BinaryParser (Get r) |

The result of a partial parse

Failed String | the parse failed with the given error message |

Finished ByteString a | the parse finished and produced the given list of results doing so. Any unparsed data is returned. |

Partial (ByteString -> Result a) | the parse ran out of data before finishing, but produced the given list of results before doing so. To continue the parse pass more data to the given continuation |

runGet :: Get r r -> ByteString -> Result rSource

Start a parser and return the first Result.

# Utility

Get the number of remaining unparsed bytes. Useful for checking whether all input has been consumed.

Test whether all input has been consumed, i.e. there are no remaining unparsed bytes.

plus :: Get r a -> Get r a -> Get r aSource

This is the choice operator. If the first option fails, the second is tried. The failure of the first option must happen within this function otherwise rollback is not attempted.

# Parsing particular types

## ByteStrings

getByteString :: Int -> Get r ByteStringSource

An efficient `get`

method for strict ByteStrings. Fails if fewer
than `n`

bytes are left in the input.

## Big-endian reads

getWord16be :: Get r Word16Source

getWord32be :: Get r Word32Source

getWord64be :: Get r Word64Source

## Little-endian reads

getWord16le :: Get r Word16Source

getWord32le :: Get r Word32Source

getWord64le :: Get r Word64Source

## Host-endian, unaligned reads

getWordhost :: Get r WordSource

getWord16host :: Get r Word16Source

getWord32host :: Get r Word32Source

getWord64host :: Get r Word64Source