On Tue, Jul 1, 2014 at 5:38 PM, Philippe Veber <philippe.veber@gmail.com> wrote:
> Reposting this question here, just in case.
>
> ---------- Forwarded message ----------
> From: Philippe Veber <philippe.veber@gmail.com>
> Date: 2014-06-28 21:32 GMT+02:00
> Subject: Toplevel and syntax extension.
> To: ocaml_beginners@yahoogroups.com
>
>
> Dear camlers,
>
> Consider the following script:
>
> #use "topfind";;
> #camlp4o;;
> #require "sexplib.syntax";;
>
> open Sexplib.Std;;
>
> type t = int with sexp;;
>
> Saved as script.ml, the simple call:
>
> ocaml script.ml
>
> fails while the call:
>
> cat script.ml | ocaml
>
> succeeds. Any idea how I could fix the first call?

How does the first call fail? A difference between the two is that, in
the second, the .ocamlinit file is used. If you are using opam with
ocamlfind installed via it, this file will contain your Topdirs setup.
You can try:

let () =
  try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH")
  with Not_found -> ()
;;

at the top of your script (after hashbang but before directives).

Hope this helps,

David