Lightweight Ruby
C Ruby Yacc C++ Batchfile Shell
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benchmark Some cosmetic changes Nov 22, 2017
bin add mruby sources Apr 20, 2012
doc Fix misspelling words in comments Aug 10, 2018
examples Always use `MRB_USE_IV_SEGLIST`. Jul 27, 2017
include Fix misspelling words in comments Aug 10, 2018
lib Run tests parallelly for each target. Jun 22, 2018
mrbgems Try to fix a fragile `File#mtime` test. Aug 13, 2018
mrblib Make `` to accept both integers and floats. Aug 13, 2018
src irep is released when Fiber is terminated Aug 6, 2018
tasks Add ~/Android/Sdk/ndk-bundle as default NDK home Jul 4, 2018
test Fix misspelling words in comments Aug 10, 2018
.gitignore Add `cscope.files` to `.gitignore`. Oct 1, 2017
.gitlab-ci.yml Gitlab tests for multiple configurations Feb 16, 2017
.travis.yml Set jobs to 4 since it have 2 CPUs. Jun 20, 2018
.yardopts Improved mrb_args_format table Oct 20, 2015
AUTHORS Upadte AUTHORS Oct 11, 2017 Fix typos in documentation and error messages [skip ci] Jun 19, 2015
LEGAL Change mruby-random License to MIT Apr 8, 2013
MITL Set the mruby-1.4.0 release date to `2018-1-16`. Jan 16, 2018
Makefile remove trailing spaces Apr 30, 2014
NEWS add document Apr 20, 2012 Set the mruby-1.4.1 release date to `2018-4-27`. Apr 27, 2018
Rakefile Run tests parallelly for each target. Jun 22, 2018
TODO update TODO entries; close #2831 Nov 16, 2015
appveyor.yml Use Ruby 2.4 instead of AppVeyor's Default(Ruby 1.9) Oct 24, 2017
appveyor_config.rb Turn on method cache for AppVeyor CI Oct 24, 2017
build_config.rb Turn off `enable_debug` flag in `build_config.rb` by default. Jun 20, 2018
minirake Fix misspelling words in comments Aug 10, 2018
mruby-source.gemspec Switch gem API to constants only Sep 6, 2015
travis_config.rb Turn on method cache for Travis CI. Aug 25, 2017

Build Status

What is mruby

mruby is the lightweight implementation of the Ruby language complying to (part of) the ISO standard. Its syntax is Ruby 1.9 compatible.

mruby can be linked and embedded within your application. We provide the interpreter program "mruby" and the interactive mruby shell "mirb" as examples. You can also compile Ruby programs into compiled byte code using the mruby compiler "mrbc". All those tools reside in the "bin" directory. "mrbc" is also able to generate compiled byte code in a C source file, see the "mrbtest" program under the "test" directory for an example.

This achievement was sponsored by the Regional Innovation Creation R&D Programs of the Ministry of Economy, Trade and Industry of Japan.

How to get mruby

The stable version 1.4.1 of mruby can be downloaded via the following URL:

The latest development version of mruby can be downloaded via the following URL:

The trunk of the mruby source tree can be checked out with the following command:

$ git clone

You can also install and compile mruby using ruby-install, ruby-build or rvm.

mruby home-page

The URL of the mruby home-page is:

Mailing list

We don't have a mailing list, but you can use GitHub issues.

How to compile and install (mruby and gems)

See the doc/guides/ file.

Running Tests

To run the tests, execute the following from the project's root directory.

$ make test


$ ruby ./minirake test

How to customize mruby (mrbgems)

mruby contains a package manager called mrbgems. To create extensions in C and/or Ruby you should create a GEM. For a documentation of how to use mrbgems consult the file doc/guides/ For example code of how to use mrbgems look into the folder examples/mrbgems/.


mruby is released under the MIT License.

Note for License

mruby has chosen a MIT License due to its permissive license allowing developers to target various environments such as embedded systems. However, the license requires the display of the copyright notice and license information in manuals for instance. Doing so for big projects can be complicated or troublesome. This is why mruby has decided to display "mruby developers" as the copyright name to make it simple conventionally. In the future, mruby might ask you to distribute your new code (that you will commit,) under the MIT License as a member of "mruby developers" but contributors will keep their copyright. (We did not intend for contributors to transfer or waive their copyrights, Actual copyright holder name (contributors) will be listed in the AUTHORS file.)

Please ask us if you want to distribute your code under another license.

How to Contribute

See the contribution guidelines, and then send a pull request to We consider you have granted non-exclusive right to your contributed code under MIT license. If you want to be named as one of mruby developers, please include an update to the AUTHORS file in your pull request.