systems.manifold:manifold-tuple (maven):  Manifold is a Java compiler plugin, its features include Metaprogramming, Properties, Extension Methods, Operator Overloading, Templates, a Preprocessor, and more. 
Keywords: android-studio|delegation|duck-typing|extension-methods|graphql|graphql-java|intellij|java|java-development|java-tooling|js-java-interoperability|json|manifold|manifold-systems|metaprogramming|preprocessor|reflection-framework|structural-typing|template-engine|type-providers