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

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

Installation

Clone the repository from github:

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

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

Usage

After making sure the library is in your code path, fire up an Erlang shell.
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").

This will place arithmetic.erl in the same directory as the .peg file by default.

Contributing