Neotoma

About

Neotoma is a packrat parser-generator for Erlang for Parsing Expression Grammars (PEGs).
It consists of a parsing-combinator library with memoization routines, a parser for PEGs,
and a utility to generate parsers from PEGs. It is inspired by treetop, a Ruby library with
similar aims, and parsec, the parser-combinator library for Haskell.

Neotoma is licensed under the MIT License (see LICENSE).

Features

1. Simple, declarative parsers generated from even simpler grammars.
2. Fully integrated, single-pass lexical and syntactic analysis (a feature of PEGs).
3. Packrat-style memoization, boasting parse-time bound linearly to the input size (at the expense of memory usage).
4. In-place semantic analysis/transformation, supporting single-pass end-to-end in some applications.
5. Erlang code-generation for the lexical/syntactic analysis piece, with the option of semantic analysis/transformation in a separate module.
6. Line/column number tracking for easy resolution of parsing errors.

Installation

1. Clone the repository from github:

   $ git clone git://github.com/seancribbs/neotoma.git

2. Symlink or copy the cloned repository to somewhere in your Erlang code path. $ERLANG_HOME/lib is best.
3. Build the source:

   $ rake

   
   Building currently requires Ruby 1.8 or later and the rake RubyGem.

Usage

1. After making sure the library is in your code path, fire up an Erlang shell.
2. To generate a parser from a PEG, use peg_gen:file/1,2 (more detailed documentation pending). For PEG examples, see the extra/ directory in the repository.

1> peg_gen:file("extra/arithmetic.peg").

Contributing

Please send pull-requests to ‘seancribbs’ on github. When submitting a patch, eunit tests are strongly encouraged.