Fast Gherkin lexer and parser based on Ragel. Gherkin is two things:

  • The language that has evolved out of the Cucumber project.

  • This library

Supported platforms:

  • Ruby 1.8.6-1.9.2 (MRI, JRuby, REE, Rubinius)

  • Pure Java

  • .NET

  • IronRuby (experimental)

  • Javascript (coming soon)

Installing the toolchain

Due to the cross-platform nature of this library, you have to install a lot of tools to build gherkin yourself. In order to make it easier for occasional contributors to get the development environment up and running, you don't have to install everything up front. The build scripts should tell you if you are missing something. For example, you shouldn't have to install MinGW to build windows binaries if you are a Linux user and just want to fix a bug in the C code.

Common dependencies

These are the minimal tools you need to install, even if you are building non-Ruby packages.

  • Ragel (brew install ragel or apt-get install ragel)

  • Ruby (any version should do).

  • A clone of the cucumber git repo to a “cucumber” sibling folder of your gherkin folder. (Only needed to run cucumber tests)

  • RVM (you may not need this if you are only building for a single platform)

With this minimal toolchain installed, install Ruby gems needed by the build:

gem install bundler
bundle install

Running RSpec and Cucumber tests

rake clean spec cucumber

If the RL_LANGS environment variable is set, only the parsers for the languages specified there will be built. E.g. in Bash, export RL_LANGS=“en,fr,no”. This can be quite helpful when modifying the Ragel grammar.

See subsections for building for a specific platform.

MRI, REE or Rubinius

You'll need GCC installed.

Build the gem with:

rake build

Pure Java and JRuby

You must install JRuby to build the pure Java jar or the JRuby gem:

rvm install jruby
rvm use jruby
rvm gemset create cucumber
rvm use @cucumber
gem install bundler
bundle install

Now you can build the jar with:

rake clean jar

.NET and IronRuby

You must install Mono and IKVM to build the pure .NET dll and the IronRuby gem:

  • Install Mono from and make sure it's on your $PATH

  • Download IKVM from and extract it to /usr/local/ikvm so that you have a /usr/local/ikvm/bin/ikvmc.exe

Now you can build the .NET dll with:

rake ikvm

MinGW Rubies (for Windows gems)

You must install MinGW rubies to build gems fow Windows. First you need to download and install MinGW:

OS X users can get it from Once you have installed it, add this to your .bashrc:

export PATH=$PATH:/usr/local/i386-mingw32-4.3.0/bin

Now, let's install some rubies. Make sure you have openssl installed first.

brew install openssl

# 1.8.6
# Don't worry about inconsistent patchlevels here. It works.
rvm install 1.8.6-p399
rvm use 1.8.6-p399
rvm gemset create cucumber
rvm use @cucumber
gem install bundler
bundle install
rake-compiler cross-ruby VERSION=1.8.6-p287

# 1.9.1
# Later 1.9.1 patch levels or 1.9.2 don't compile on mingw.
# The compiled binaries should still work on 1.9.2
rvm install 1.9.1-p243
rvm use 1.9.1-p243
rvm gemset create cucumber
rvm use @cucumber
gem install bundler
bundle install
rake-compiler cross-ruby VERSION=1.9.1-p243

Release process

  • Bump version in the VERSION file and:

** java/pom.xml ** ikvm/Gherkin/Gherkin.csproj

  • Commit changes.

  • rake gems:prepare && ./ && rake release:ALL

  • Announce on Cucumber list, IRC and Twitter.

Configuring Rake-Compiler for cross compilation

In order to build Windows binaries (so we can release Windows gems from OS X/Linux) we need to set up rake-compiler.

I didn't want to install macports (I'm on homebrew) and I couldn't figure out how to build MinGW myself. I got prebuilt binaries (version 4.3.0): - just add the bin folder to your PATH

Note on Patches/Pull Requests

  • Fork the project.

  • Run rake ragel:rb to generate all the I18n lexers

  • Make your feature addition or bug fix.

  • Add tests for it. This is important so I don't break it in a future version unintentionally.

  • Commit, do not mess with Rakefile, VERSION, or History.txt. (if you want to have your own version, that is fine but

    bump version in a commit by itself I can ignore when I pull)
  • Send me a pull request. Bonus points for topic branches.

Copyright © 2009-2010 Mike Sassak, Gregory Hnatiuk, Aslak Hellesøy. See LICENSE for details.