This gem adds support for the ANTLR4 runtime for Ruby lexers and parsers generated from the Ruby langauge target available at

Generate Your Ruby ANTLR4 Grammar

In a clean directory:

$ git clone [email protected]:twalmsley/antlr4.git
$ cd antlr4
$ git checkout ruby_dev
$ export MAVEN_OPTS="-Xmx1G"
$ mvn clean
$ mvn -DskipTests install
$ cd <my-grammar-directory>
$ java -jar ~/.m2/repository/org/antlr/antlr4/4.7.3-SNAPSHOT/antlr4-4.7.3-SNAPSHOT-complete.jar \
   -o <output_dir_full_path> \
   -listener \
   -visitor \
   -package MYGrammar \
   -Dlanguage=Ruby \
   MYGrammarLexer.g4 MYGrammarParser.g4


Add this line to your application's Gemfile:

gem 'antlr4-runtime'

And then execute:

$ bundle install

Or clone the repository and build and install it yourself as:

$ rake install

or if that fails:

$ sudo rake install


require './MYGrammarParserListener'
require './MYGrammarParserBaseListener'
require './MYGrammarParserVisitor'
require './MYGrammarLexer'
require './MYGrammarParser'

str = 'a=b'
lexer =, 'String'))

tokens =

parser =

parsed =


After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Antlr4::Runtime project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.