# scanner
Fast non-backtracking incremental combinator parsing for bytestrings

[![Build Status](https://travis-ci.org/Yuras/scanner.svg?branch=master)](https://travis-ci.org/Yuras/scanner)

On hackage: http://hackage.haskell.org/package/scanner

On stackage: https://www.stackage.org/package/scanner

It is often convinient to use backtracking to parse some sophisticated
input. Unfortunately it kills performance, so usually you should avoid
backtracking.

Often (actually always, but it could be too hard sometimes) you can
implement your parser without any backtracking. It that case all the
bookkeeping usuall parser combinators do becomes unnecessary. The
scanner library is designed for such cases. It is often 2 times faster
then attoparsec.

As an example, please checkout redis protocol parser included into the
repo, both using attoparsec and scanner libraries:
https://github.com/Yuras/scanner/tree/master/examples/Redis

Benchmark results:

![Bechmark results](https://raw.githubusercontent.com/Yuras/scanner/master/bench/bench.png)

But if you really really really need backtracking, then you can just
inject attoparsec parser into a scanner: http://hackage.haskell.org/package/scanner-attoparsec