Lots of new goodies in this release, which you should be familiar with if you've been following my journal lately. I'm too lazy to be keeping a work log at this early stage of the project, so a comprehensive list of changes isn't available, sorry.
The main goodies are tuples and structures (records). Please note that support isn't fully first-class yet - passing tuples/structures to functions isn't totally implemented, for example. I expect to shore up that kind of stuff shortly.
Enjoy R4, and as usual, your comments and feedback are requested; if you encounter any shortcomings that you'd like to see fixed sooner rather than later, please feel free to let me know.
[edit] Link fixed.