Dear Caml list, I am pleased to announce an experimental branch of the O'Caml compiler: O'Caml extended with Generalized Algebraic Datatypes. You can find more information on this webpage: https://sites.google.com/site/ocamlgadt/ And you can grab the latest release here: svn checkout https://yquem.inria.fr/caml/svn/ocaml/branches/gadts Any feedback would be very much appreciated. Sincerely, Jacques Le Normand