Polyglot for Maven is a set of extensions for Maven 3.3.1+ that allows the POM model to be written in dialects other than XML. Several of the dialects also allow inlined plugins: the Ruby, Groovy and Scala dialects allow this.

Here's an example POM written in the Ruby dialect:

project 'Polyglot :: Aggregator' do

  model_version '4.0.0'
  id 'io.tesla.polyglot:tesla-polyglot:0.0.1-SNAPSHOT'
  inherit 'io.tesla:tesla:4'
  packaging 'pom'

  properties( 'sisuInjectVersion' => '0.0.0.M2a',
              'teslaVersion' => '3.1.0' )

  modules [ 'tesla-polyglot-common',
            'tesla-polyglot-atom',
            'tesla-polyglot-ruby',
            'tesla-polyglot-groovy',
            'tesla-polyglot-yaml',
            'tesla-polyglot-clojure',
            'tesla-polyglot-scala',
            'tesla-polyglot-java',
            'tesla-polyglot-xml',
            'tesla-polyglot-cli',
            'tesla-polyglot-maven-plugin' ]

  overrides do
    jar 'org.eclipse.sisu:org.eclipse.sisu.inject:${sisuInjectVersion}'
    jar 'org.eclipse.sisu:org.eclipse.sisu.plexus:${sisuInjectVersion}'
    jar 'org.apache.maven:maven-model-builder:3.1.0'
    jar 'org.apache.maven:maven-embedder:3.1.0'
    jar( 'junit:junit:4.11', :scope => 'test' )

  end

  plugin 'org.codehaus.plexus:plexus-component-metadata:1.5.4' do
    execute_goals 'generate-metadata', 'generate-test-metadata'
  end

  build do
    execute("first", :validate) do |context|
      puts "Hello from JRuby!"
    end
  end
end

• Maven 3.3.1+
• Java 7+

To use Polyglot for Maven you need to edit ${maven.multiModuleProjectDirectory}/.mvn/extensions.xml and add the appropriate language extension.

The available languages, in alphabetical order, with their artifact id are:

The groupId value is io.takari.polyglot.

Edit the extensions.xml file and add the following, replacing ARTIFACTID with the artifactId for your chosen language.

<?xml version="1.0" encoding="UTF-8"?>
<extensions>
  <extension>
    <groupId>io.takari.polyglot</groupId>
    <artifactId>ARTIFACTID</artifactId>
    <version>0.3.0</version>
  </extension>
</extensions>

We have created a simple Maven plugin that will help you convert any existing pom.xml files:

mvn io.takari.polyglot:polyglot-translate-plugin:translate \
  -Dinput=pom.xml -Doutput=pom.{format}

Where the supported formats are rb, groovy, scala, yaml, atom, java and of course xml. See here for more info. You can even convert back to xml or cross-convert between all supported formats.

The whole interoperability story has not been worked out but you can create a XML-formatted POM from the Polyglot version. Currently mixing different dialects within a reactor is not supported.

A pom.xml will currently not be installed or deployed except for the Ruby DSL and the Scala DSL but we are working towards this feature for all DSLs.

Some support in IDE's like IntelliJ IDEA and Eclipse exist and the different markup languages are understood by various syntax highlighters. However, full integration of the markup syntax and the specific Maven-related aspects is not available.

Maven plugins or Maven plugin goals that rely on the XML format are not supported, since they are either attempting to parse the XML directly or modify it in automated fashion do not work with Polyglot Maven. Examples are:

• Maven Relase Plugin
• Maven Versions Plugin (goals that don't edit the pom.xml (like e.g. display-dependency-updates) work as expected though)

Fixes would have to be implemented in these plugins. Workarounds or replacement workflows for most usecases exist.

Despite the warning above, Polyglot Maven is pretty stable right now. Have a look at the integration tests for each dialect in this repository for some examples as well as our dedicated polyglot-maven-examples project.

The following projects are real world usage examples that use Polyglot Maven in their regular development and release work:

• https://github.com/jruby - Extensive usage of Polyglot Ruby and contributions to the project from the team, and is recommended when creating java extensions for jruby.

• The ruby-processing project has examples of creating java extensions for jruby (see JRubyArt and propane builds) as well as simpler projects where the polyglot maven is used in creating gem wrappers for processing.org java libraries (eg toxicgem and geomerative gems).

• http://snakeyaml.org - Extensive usage of Polyglot YAML and contributions to the project from the team.

• https://urbanise.com - Using Polyglot YAML for building next generation strata management platform.

Java Projects

• LambdaTest - A simple Java project with a standalone pom.scala

• CmdOption - A Java project with a top-level reactor project and an additional shared scala file included into both pom.scalas

Scala Projects

• Domino - A simple project using Polyglot Scala.

• Blended - A complex multi-project using Polyglot Scala. It's also an example where the #include feature is heavily used to share common configuration but avoid Maven parent poms, which are often problematic.

Please let us know of your usage by filing an issue so we can add it here.