camlp4 messes with comments

[ygrek]

From http://caml.inria.fr/mantis/view.php?id=4713 and http://caml.inria.fr/mantis/view.php?id=4346

Camlp4o messes with comments, hence with ocamldoc generation of documentation.

In order for comments to be used by ocamldoc, they should come immediately before or after a value. Camlp4o moves comments away from values, hence breaks ocamldoc.

Is there any hope that this could be fixed?

Examples :

$ cat tst.ml 
 (** comment of t *)
 type t =
   {
     mutable a : int; (** a *)
     mutable b : int; (** b *)
     mutable c : int; (** c *)
     mutable d : int; (** d *)
     mutable e : int; (** e *)
   }
 (** after *)
 $ camlp4o tst.ml 
 (** comment of t *)
 type t =
   { (** a *) (** b *) (** c *) mutable a : int; mutable b : int;
     mutable c : int; mutable d : int; (** d *) mutable e : int
   }

 cat tst_bis.ml
 (** comment of t *)
 type t =
   {
     mutable a : int; (** a *)
     mutable b : int; (** b *)
     mutable c : int; (** c *)
     mutable d : int; (** d *)
     mutable e : int; (** e *)
   }
 (** after *)
 ()
 $ camlp4o tst_bis.ml
 (** comment of t *)
 type t =
   { (** a *) (** b *) (** c *) mutable a : int; mutable b : int;
     mutable c : int; mutable d : int; (** d *) mutable e : int
   }
 (** e *)
 (** after *)
 let _ = ()

Old patch with partial fix :

diff --exclude=.svn -ur /home/ygrek/work/contrib/ocaml/3.11/camlp4/Camlp4/Printers/OCaml.ml camlp4/Camlp4/Printers/OCaml.ml
--- /home/ygrek/work/contrib/ocaml/3.11/camlp4/Camlp4/Printers/OCaml.ml 2009-10-31 13:58:04.000000000 +0200
+++ camlp4/Camlp4/Printers/OCaml.ml 2009-12-31 14:39:27.000000000 +0200
@@ -152,6 +152,13 @@
           do_print_comments_before loc f s
     | [: :] -> () ];

+  value rec do_print_all_comments loc f =
+    parser
+    [ [: ` (comm, comm_loc); s :] ->
+          let () = f comm comm_loc in
+          do_print_all_comments loc f s
+    | [: :] -> () ];
+
   class printer ?curry_constr:(init_curry_constr = False) ?(comments = True) () =
   object (o)

@@ -737,7 +744,7 @@
         <:sig_item< $<:sig_item<>>$; $sg$ >> ->
           o#sig_item f sg
       | <:sig_item< $sg1$; $sg2$ >> ->
-          do { o#sig_item f sg1; cut f; o#sig_item f sg2 }
+          do { o#sig_item f sg1; o#node f sg2 Ast.loc_of_sig_item; cut f; o#sig_item f sg2 }
       | <:sig_item< exception $t$ >> ->
           pp f "@[<2>exception@ %a%(%)@]" o#ctyp t semisep
       | <:sig_item< external $s$ : $t$ = $sl$ >> ->
@@ -1012,7 +1019,13 @@
       [ <:str_item< $exp:e$ >> -> pp f "@[<0>%a%(%)@]@." o#expr e semisep
       | st -> pp f "@[<v0>%a@]@." o#str_item st ];

-    method interf f sg = pp f "@[<v0>%a@]@." o#sig_item sg;
+    method interf f sg = 
+      let () = pp f "@[<v0>%a@]" o#sig_item sg in
+      let loc = Ast.loc_of_sig_item sg in
+      let () = do_print_all_comments loc (fun c _ -> pp f "%s@ " c)
+        (CommentFilter.take_stream comment_filter) in
+      pp f "@.";
+
   end;

   value with_outfile output_file fct arg =

[samoht]

+1

This is quite annoying (especially since we start having tools which extract and display the comments in a nice way).