caml-list - the Caml user's mailing list
 help / Atom feed
From: Frédéric Fort <frederic.fort@univ-lille.fr>
To: caml-list@inria.fr
Subject: [Caml-list] Dynlink plugin reevaluates modules of main program
Date: Thu, 8 Nov 2018 11:05:14 +0100 (CET)
Message-ID: <1238750250.1711857.1541671514743.JavaMail.zimbra@univ-lille.fr> (raw)

Hello,

I have an existing program and would like to allow to extend it's functionalities with plugins.
If I simplify my code structure it looks as follows:
 - a.ml : "main module" of the program
 - b.ml : additional definitions used in a.ml
 - c.ml : interface for plugins (a collection of function refs)
 - d.ml : plugin I would like to load

Now, d.ml uses values defined in b.ml. Some of them are of type string ref
and it seems that the code of b.ml is reevaluated when I call
Dynlink.loadfile "/path/to/d.cmxs" which resets them to the empty string.

Is there a way to prevent this from happening ?
Using allow_only and prohibit is not an option, since multiple plugins would each reevaluate C
and undo each others modifications.

Yours sincerely,
Frédéric Fort

P.S.: Here follows a minimal working example.
I compiled it with
ocamlbuild -use-ocamlfind -lib dynlink a.native
ocamlbuild -use-ocamlfind d.cmxs

a.ml:
open Format

let _ =
  B.str := "abc";
  printf "%s\n" !B.str;
  begin
    try
      Dynlink.loadfile "./_build/d.cmxs"
    with Dynlink.Error err ->
      failwith (Dynlink.error_message err) end;
  printf "%s\n" !B.str;
  match !C.f with
  | Some(f) -> printf "%s\n" (f 0)
  | None -> ()

b.ml:
let str = ref ""

c.ml:
let f : (int -> string) option ref = ref None

d.ml:
let _ =
  C.f := Some((fun x -> !B.str^(string_of_int x)))

-- 
Caml-list mailing list.  Subscription management and archives:
https://sympa.inria.fr/sympa/arc/caml-list https://inbox.ocaml.org/caml-list
Forum: https://discuss.ocaml.org/
Bug reports: http://caml.inria.fr/bin/caml-bugs

             reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-08 10:05 Frédéric Fort [this message]
2018-11-08 10:23 ` Gabriel Scherer
2018-11-08 10:23 ` Nicolás Ojeda Bär
2018-11-08 13:04 ` Ivan Gotovchits
2018-11-15 16:35   ` Nicolás Ojeda Bär

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1238750250.1711857.1541671514743.JavaMail.zimbra@univ-lille.fr \
    --to=frederic.fort@univ-lille.fr \
    --cc=caml-list@inria.fr \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

caml-list - the Caml user's mailing list

Archives are clonable: git clone --mirror https://inbox.ocaml.org/caml-list

AGPL code for this site: git clone https://public-inbox.org/ public-inbox