Eclipse Golo is a dynamically-typed programming language for the Java Virtual Machine. Golo is largely interoperable with Java and other JVM languages (e.g., numeric types are boxing classes from java.lang, and collection literals leverage java.util classes). Golo supports imperative and functional programming patterns. Golo is not a strictly object-oriented programming language: it very much resembles Go in the sense that methods are just functions applied to specific receiver types. Golo or Java defined types can be augmented in Golo, that is, new methods can be made available.
The language features have been initially designed around the abilities of invokedynamic / JSR 292 that appeared in Java SE 7. Golo uses ahead-of-time compilation of bytecode. While the bytecode remains stable over a program execution, the invokedynamic-based reconfigurable call sites support the adaptive dispatch mechanisms put in place for helping the HotSpot JIT to extract reasonable performance. Golo generally exhibits good performance in micro-benchmarks for a dynamically-typed language on the JVM.
Diving into the design and implementation of a programming language is an involving task, and existing JVM languages have large codebases with rich histories. Golo explicitly wants to serve as a foundation for programming and language derivative experiments. To this end, its codebase is expected to remain concise enough to remain of pedagogical value.
Golo uses a limited set of runtime dependencies: the JavaCC parser generator, the ASM bytecode engineering library and the json-simple library. Optional runtime dependencies include JCommanderfor the command-line interface and Txtmark to process API documentations written in Markdown.
Golo does not currently have collaborations with other Eclipse projects beyond a community-contributed XText-based Eclipse IDE plugin. By joining the Eclipse Foundation, we expect cross-pollinisation with the wider Eclipse ecosystem.