ANTLR - ANTLR, ANother Tool for Language Recognition, is a language tool that provides a framework for...
Owl parser generator - Efficient and understandable parser generator.
parboiled - Elegant PEG parsing in Java - lightweight, easy-to-use, powerful.
Eclipse Xtext - The website of Eclipse Xtext, an open-source framework for development of programming languages and domain-specific languages
FLEX - An in-app debugging and exploration tool for iOS.
textX - textX is a meta-language for building Domain-Specific Languages (DSLs) in Python. It is inspired by Xtext. It will help you build your textual language easily. You can invent your own language or build a support for an existing textual language.