Hi, the documentation for the revised syntax explain that abstract types are expressed by : type bar = 'a; but ocaml returns an error. # Objective Caml version 3.11.1 Camlp4 Parsing version 3.11.1 # type bar = 'a ; Error: Unbound type parameter 'a http://caml.inria.fr/pub/docs/manual-camlp4/manual007.html Thanks, -- Serge Leblanc gpg --keyserver hkp://keyserver.ubuntu.com:11371 --recv-keys 0x33243C1B Fingerprint = 066C 005F 5595 D85C 7673 D969 1DD4 90C4 3324 3C1B