I am pleased to announce that the GADT extension to O'Caml is now complete,
apart from camlp4, and ready for testing:
svn checkout https://yquem.inria.fr/caml/svn/ocaml/branches/gadts
You can find more information here:
https://sites.google.com/site/ocamlgadt/
So please test away!
Jacques Le Normand