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Build Status

An implementation of the Oz programming language on top of Truffle and Graal.

The bootcompiler and Oz libraries are imported from Mozart 2.

Interesting Points

  • A master thesis was made with this project to optimize performance. It details many static and dynamic optimizations.

  • Tail calls are optimized and compiled as loops, see TailCallCatcherNode. Self-recursion is optimized further in SelfTailCallCatcherNode.

  • There is a Truffle AST serializer in OzSerializer using Kryo able to serialize Oz code.

  • The project uses the Coroutine patch for HotSpot to be able to create many lightweight threads.

  • The parser, typer, and some optimizations are written in Scala (bootcompiler/) and the AST produced by Scala is then translated to a Truffle AST in Translator.

Current Status

Early stage but the Panel and Browser are working.

The Panel On Mozart-Graal


  • Java 8
  • Maven 3
  • C/C++ toolchain (build-essential) for building Graal
  • Python 2.7 (for mx)
  • Ruby >= 2.2.0 (for the launcher)

Build instructions

mkdir mozart-dev
cd mozart-dev
git clone
cd mozart-graal

It takes around 5 min to build everything.

Run with



Graal is not built by default to save time. To build it, run

rake build:graal

On recent Linux, you need to do part of the build manually, see Building JVMCI.

IDE: IntelliJ IDEA

IntelliJ IDEA configuration are checked in the repository and should work out of the box. Import mozart-dev as a project.