Hello,

On 2015-09-23 13:34, Gerd Stolpmann <info@gerd-stolpmann.de> writes:

> Am Mittwoch, den 23.09.2015, 12:25 +0200 schrieb Emilio Jesús Gallego
> Arias:
>> Hi Alan,
>> 
>> 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.

Thank you for tracking down where the formatter is created. It makes
sense now why I was not able to change these margins.

> Maybe to propagate the margin?
>
> Format.pp_set_margin ppf (Format.pp_get_margin Format.std_formatter())
>
> Don't know whether std_formatter or err_formatter is the right one.

It’s not clear. The formatter for warnings is set by default to the
error formatter
(https://github.com/ocaml/ocaml/blob/b860d631458802c8685aa59c9d7b66a9225fcedb/parsing/location.ml#L309)
but the toplevel loop sets it to the std formatter (the loop is called
with std_formatter,
https://github.com/ocaml/ocaml/blob/b860d631458802c8685aa59c9d7b66a9225fcedb/parsing/location.ml#L309).
So a solution could be to reuse its value:

Format.pp_set_margin ppf (Format.pp_get_margin !formatter_for_warnings ())

Thanks again,

Alan

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