Re: [Caml-list] How can I change the margin size in the toplevel?

[gallego@cri.ensmp.fr (Emilio Jesús Gallego Arias)]

Hi Alan,

Alan Schmitt <alan.schmitt@polytechnique.org> writes:

> Thanks a lot for this suggestion. Unfortunately it does not seem to work
> in the toplevel: it’s as if the toplevel was not using
> Format.std_formatter for its output. I don’t know how to get hold of the
> formatter used in the toplevel to change its options…

Oh I see, indeed the particular problem here seems that typing errors
are first formatted to a fresh buffer formatter, which won't inherit
stderr's margin.

The code seems to have changed in the last months (likely due to color
support), but the corresponding code in trunk is at parsing/location.ml:335.

Indeed, this little hack works for me(TM):

8<--------------------------------------------------------------------8<
Index: parsing/location.ml
===================================================================
--- parsing/location.ml	(revision 16441)
+++ parsing/location.ml	(working copy)
@@ -333,6 +333,7 @@
 let pp_ksprintf ?before k fmt =
   let buf = Buffer.create 64 in
   let ppf = Format.formatter_of_buffer buf in
+  Format.pp_set_margin ppf (200 + 1);
   Misc.Color.set_color_tag_handling ppf;
   begin match before with
     | None -> ()
8<--------------------------------------------------------------------8<

I don't know what would be the proper way to integrate it upstream.

Best regards,
Emilio