We already have two usable prototypes. They are usable because they allow you to do useful computations. However, none of them implements AOP yet. These prototypes are distributed under the GNU General Public License . You can read a little explanation .
Next versions are much more usable.
In the nest versions, we intend to compile the Oil code to Tcl code to obtain really acceptable performances. User interface is also more complete than in the previous release. Performances are greatly improved by directly using Tcl lists. It's much faster than Interp-Tcl, and has a few more features. You can read the tutorial , and others docs .