mruby/mruby

Lightweight Ruby

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  "language": "C",
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  "pushedAt": "2025-11-24T14:56:21Z",
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mruby

What is mruby

mruby is the lightweight implementation of the Ruby language complying to (part of) the [ISO standard][ISO-standard] with more recent features provided by Ruby 3.x. Also, its syntax is Ruby 3.x compatible except for pattern matching.

You can link and embed mruby within your application. The “mruby” interpreter program and the interactive “mirb” shell are provided as examples. You can also compile Ruby programs into compiled byte code using the “mrbc” compiler. All these tools are located in the “bin” directory. “mrbc” can also 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

To get mruby, you can download the stable version 3.4.0 from the official mruby GitHub repository or clone the trunk of the mruby source tree with the “git clone” command. You can also install and compile mruby using ruby-install, ruby-build or rvm.

The latest development version of mruby can be downloaded via the following URL: https://github.com/mruby/mruby/zipball/master

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

$ git clone https://github.com/mruby/mruby.git

mruby homepage

The URL of the mruby homepage is: https://mruby.org.

Mailing list

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

How to compile, test, and install (mruby and gems)

For the simplest case, type

rake all test

See the [compile.md]!(doc/guides/compile.md) file for the detail.

Building documentation

There are two sets of documentation in mruby: the mruby API (generated by YARD) and C API (Doxygen and Graphviz)

To build both of them, simply go

rake doc

You can also view them in your browser

rake view_api
rake view_capi

How to customize mruby (mrbgems)

mruby contains a package manager called “mrbgems” that you can use to create extensions in C and/or Ruby. For a guide on how to use mrbgems, consult the [mrbgems.md]!(doc/guides/mrbgems.md) file, and for example code, refer to the [examples/mrbgems/]!(examples/mrbgems) folder.

Index of Document

[About the Limitations of mruby]!(doc/limitations.md)
[About the Compile]!(doc/guides/compile.md)
[About the Debugger with the mrdb Command]!(doc/guides/debugger.md)
[About GC Arena]!(doc/guides/gc-arena-howto.md)
[About the mruby directory structure]!(doc/guides/hier.md)
[About Linking with libmruby]!(doc/guides/link.md)
[About Memory Allocator Customization]!(doc/guides/memory.md)
[About Build-time Configurations]!(doc/guides/mrbconf.md)
[About the Build-time Library Manager]!(doc/guides/mrbgems.md)
[About the Symbols]!(doc/guides/symbol.md)
[Internal Implementation / About Value Boxing]!(doc/internal/boxing.md)
[Internal Implementation / About mruby Virtual Machine Instructions]!(doc/internal/opcode.md)

License

mruby is released under the [MIT License]!(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]!(AUTHORS) file.)

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

How to Contribute

To contribute to mruby, please refer to the [contribution guidelines][contribution-guidelines] and send a pull request to the mruby GitHub repository. By contributing, you grant non-exclusive rights to your code under the MIT License.

[ISO-standard] !: https://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=59579 [contribution-guidelines] !: CONTRIBUTING.md