Fabric Language Ruby

The mod enables a Ruby language adapter for Fabric Loader, so a mod can be written in Ruby instead of Java or Kotlin. The JRuby runtime, along with the Ruby standard library, ships inside the mod jar, so no separate Ruby install is needed. A Ruby mod names a script in its metadata, and the adapter starts JRuby only when that entrypoint is needed. The script is evaluated, and its resulting object is handed to Fabric Loader as a regular entrypoint.

Ruby method names are matched to Java interface methods without manual wiring, so a class that defines initialize and onInitialize can implement ModInitializer. Method-reference and lambda entrypoints cover single-method interfaces, while multi-method interfaces are implemented through a class in the module. Each mod should use a unique directory name, because all mods share one JVM classpath.

Files are published for Fabric only, and Fabric Loader 0.16.0 or newer is required. Fabric Language Ruby is open source under the MIT License and is compatible with fabric-language-kotlin. The mod works on either side, and neither the client nor the server needs it, though a server running Ruby mods will want it.