[Caml-list] how to apply an attribute on ppx output

[Caml-list] how to apply an attribute on ppx output

[Ashish Agarwal]

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$ cat foo.mli
type t

$ cat foo.ml
type t = {a:int} [@@deriving fields]

$ ocamlfind ocamlc -package ppx_fields_conv,fieldslib -w A -c foo.mli

$ ocamlfind ocamlc -package ppx_fields_conv,fieldslib -w A -c foo.ml
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value names.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value make_creator.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value create.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value map.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value iter.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value fold.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value map_poly.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value for_all.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value exists.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value to_list.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value iter.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value fold.
File "foo.ml", line 1, characters 5-6:
Warning 32: unused value set_all_mutable_fields.

Thus, I'd like to disable warning 32, but only for the items generated by
the ppx extension. I've tried adding [@@warning "-32"] in various places
but it understandably doesn't work. So then I tried defining an internal
module and disabling in the entire module like this:

$ cat foo.ml
module T = struct
  [@@warning "-32"]
  type t = {a:int} [@@deriving fields]
end
include T

However I get a syntax error, even though this follows the example of the
manual in section 7.221
<http://caml.inria.fr/pub/docs/manual-ocaml/extn.html#sec242>. Is this a
bug in the manual? According to the grammar it seems the attribute should
be added after the module expression:

$ cat foo.ml
module T = struct
  type t = {a:int} [@@deriving fields]
end [@@warning "-32"]

include T

This compiles, but the warnings don't go away. Is there a solution?

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Re: [Caml-list] how to apply an attribute on ppx output

[Leo White]

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> $ cat foo.ml module T = struct  [@@warning "-32"]  type t = {a:int}
> [@@deriving fields] end include T
>
> However I get a syntax error, even though this follows the example of
> the manual in section 7.221[1]. Is this a bug in the manual?

I think that's a typo in the manual: it should be [@@@warning "-32"]
(with *three* at symbols).

Regards,

Leo


Links:

  1. http://caml.inria.fr/pub/docs/manual-ocaml/extn.html#sec242

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Re: [Caml-list] how to apply an attribute on ppx output

[octachron]

> I think that's a typo in the manual: it should be [@@@warning "-32"] 
> (with *three* at symbols).
> Regards,
> Leo

It is a typo in the manual – that have already been corrected in the dev 
version of the manual.

Regards,
octachron.

Re: [Caml-list] how to apply an attribute on ppx output

[Ashish Agarwal]

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Thanks.

On Tue, Nov 24, 2015 at 2:25 PM, octachron <octa@polychoron.fr> wrote:

>
> I think that's a typo in the manual: it should be [@@@warning "-32"] (with
>> *three* at symbols).
>> Regards,
>> Leo
>>
>
> It is a typo in the manual – that have already been corrected in the dev
> version of the manual.
>
> Regards,
> octachron.
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
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>

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Re: [Caml-list] how to apply an attribute on ppx output

[Jeremie Dimino]

BTW, if you use ppx_driver, it will use the specific ppx_type_conv
backend which automatically prevents warning 32 on all values
generated by derivers:

$ ocamlfind ocamlopt -predicates ppx_driver -o ppx -linkpkg -package
ppx_fields_conv ppx_driver_runner.cmxa
$ ocamlfind ocamlc -pp ./ppx -package fieldslib -w A -c foo.mli
$ ocamlfind ocamlc -pp ./ppx -package fieldslib -w A -c foo.ml

On Tue, Nov 24, 2015 at 9:17 PM, Ashish Agarwal <agarwal1975@gmail.com> wrote:
> Thanks.
>
> On Tue, Nov 24, 2015 at 2:25 PM, octachron <octa@polychoron.fr> wrote:
>>
>>
>>> I think that's a typo in the manual: it should be [@@@warning "-32"]
>>> (with *three* at symbols).
>>> Regards,
>>> Leo
>>
>>
>> It is a typo in the manual – that have already been corrected in the dev
>> version of the manual.
>>
>> Regards,
>> octachron.
>>
>> --
>> Caml-list mailing list.  Subscription management and archives:
>> https://sympa.inria.fr/sympa/arc/caml-list
>> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
>> Bug reports: http://caml.inria.fr/bin/caml-bugs
>
>



-- 
Jeremie