Scanner.Internal

scanner-0.2: Fast non-backtracking incremental combinator parsing for bytestrings

Safe Haskell | None
Language | Haskell2010

Scanner.Internal

Description

Scanner implementation

Synopsis

- newtype Scanner a = Scanner {
  - run :: forall r. ByteString -> Next a r -> Result r
  }
- type Next a r = ByteString -> a -> Result r
- data Result r
  - = Done ByteString r
  - | Fail ByteString String
  - | More (ByteString -> Result r)
- scan :: Scanner r -> ByteString -> Result r
- anyWord8 :: Scanner Word8
- takeWhile :: (Word8 -> Bool) -> Scanner ByteString
- take :: Int -> Scanner ByteString
- endOfInput :: Scanner Bool
- string :: ByteString -> Scanner ()
- lookAhead :: Scanner (Maybe Word8)

# Documentation

newtype Scanner a

CPS scanner without backtracking

Constructors

Scanner |
Fields run :: forall r. ByteString -> Next a r -> Result r

Instances

Monad Scanner |
Functor Scanner |
Applicative Scanner |

type Next a r = ByteString -> a -> Result r

Scanner continuation

data Result r

Scanner result

Constructors

Done ByteString r | Successful result with the rest of input
Fail ByteString String | Scanner failed with rest of input and error message
More (ByteString -> Result r) | Need more input

scan :: Scanner r -> ByteString -> Result r

Run scanner with the input

anyWord8 :: Scanner Word8

Consume the next word

It fails if end of input

takeWhile :: (Word8 -> Bool) -> Scanner ByteString

Take input while the predicate is `True`

take :: Int -> Scanner ByteString

Take the specified number of bytes

endOfInput :: Scanner Bool

Returns `True` when there is no more input

string :: ByteString -> Scanner ()

Consume the specified string

Warning: it is not optimized yet, so for for small string it is better to consume it byte-by-byte using `word8`

lookAhead :: Scanner (Maybe Word8)

Return the next byte, if any, without consuming it