attoparsec- Fast combinator parsing for bytestrings and text

Safe HaskellNone



Simple, efficient parser combinators for strings, loosely based on the Parsec library.



data Parser i a Source

The core parser type. This is parameterised over the types i of string being processed and t of internal state representation.

This type is an instance of the following classes:

  • Monad, where fail throws an exception (i.e. fails) with an error message.
  • Functor and Applicative, which follow the usual definitions.
  • MonadPlus, where mzero fails (with no error message) and mplus executes the right-hand parser if the left-hand one fails. When the parser on the right executes, the input is reset to the same state as the parser on the left started with. (In other words, attoparsec is a backtracking parser that supports arbitrary lookahead.)
  • Alternative, which follows MonadPlus.


data IResult i r Source

The result of a parse. This is parameterised over the type i of string that was processed.

This type is an instance of Functor, where fmap transforms the value in a Done result.


Fail i [String] String

The parse failed. The i parameter is the input that had not yet been consumed when the failure occurred. The [String] is a list of contexts in which the error occurred. The String is the message describing the error, if any.

Partial (i -> IResult i r)

Supply this continuation with more input so that the parser can resume. To indicate that no more input is available, pass an empty string to the continuation.

__Note__: if you get a Partial result, do not call its continuation more than once.

Done i r

The parse succeeded. The i parameter is the input that had not yet been consumed (if any) when the parse succeeded.


Functor (IResult i) 
(Show i, Show r) => Show (IResult i r) 
(NFData i, NFData r) => NFData (IResult i r) 

class Monoid c => Chunk c whereSource

A common interface for input chunks.


chunkElemToChar :: c -> ChunkElem c -> CharSource

Map an element to the corresponding character. The first argument is ignored.