Re:VIEW is a digital publishing system for books and ebooks. It supports InDesign, EPUB and LaTeX. This gem is experimental version with PEG grammar

A dynamic language targeting the Rubinius VM, focusing on extensibility and expressiveness through macros and pattern-matching.

RFC Compliant Email Address Parsing using the KPEG grammars.

Gem to allow APL array operations in Ruby

simple and customizable text markup language for EPUB

hypertextual documents using plain old data structures

Parsing and compilation tools for Surveyor surveys

Simple and customizable text markup language for EPUB/XHTML

ParseJS is a JavaScript parser written using KPeg

Tools for interacting with Wesnoth Markup Language, MP Server and such.