The Étoilé runtime can be found in subversion at:
Key features include:
- Two layer model, with Self-like object model at the core and classes built on top.
- Very small code base (roughly 10% of the size of the GNU runtime)
- Support for @synchronized on all objects / classes.
- Concrete protocols, mixins and Smalltalk-style traits.
- Prototype-based object orientation (can be mixed with class-based; classes really are just another kind of object in this runtime)
- Safe method caching (including polymorphic inline caching) with low overhead.
- Fast accessor methods (we can implement properties that are much faster than Apple's)