[Caml-list] pre-process myocamlbuild.ml with ocamlbuild ...

[Caml-list] pre-process myocamlbuild.ml with ocamlbuild ...

[Pietro Abate]

Hi all,

maybe, not the best subject of the week, I know . I'd like to
pre-process the file myocamlbuild.ml with cppo before building it. The
reason is that I have a few unused ocamlbuild tags in my _tags file
(that is auto generated by a script ...), and I'd like to remove all
warnings using 

#ifdef OCAML4022
Ocamlbuild_pack.Flags.mark_tag_used "use_" ;;
Ocamlbuild_pack.Flags.mark_tag_used "pkg_" ;;
Ocamlbuild_pack.Flags.mark_tag_used "link_" ;;
#endif

The problem is that Ocamlbuild_pack.Flags.mark_tag_used exists only 
with ocamlbuild < 4.02 .

my naive idea is to pass ocamlbuild a preprocessing tag of the form
-plugin-tag "pp(cppo)" and then let it handle the rest.

But apparently this does not work. How can I convince ocamlbuild to 
build my plugin using a preprocessing step ?

Instead of this :
e$ocamlbuild
+ /usr/bin/ocamlopt.opt unix.cmxa -I /usr/lib/ocaml/ocamlbuild /usr/lib/ocaml/ocamlbuild/ocamlbuildlib.cmxa myocamlbuild.ml /usr/lib/ocaml/ocamlbuild/ocamlbuild.cmx -o myocamlbuild
File "myocamlbuild.ml", line 5, characters 0-1:
Error: Syntax error

I'd like to build it as : 
$/usr/bin/ocamlopt.opt unix.cmxa -I /usr/lib/ocaml/ocamlbuild /usr/lib/ocaml/ocamlbuild/ocamlbuildlib.cmxa -pp "cppo" myocamlbuild.ml /usr/lib/ocaml/ocamlbuild/ocamlbuild.cmx -o myocamlbuild

what is the magic ocamlbuild incantation ? Or alternatively, Do you
see another solution to my small problem ?

thanks,
p

Re: [Caml-list] pre-process myocamlbuild.ml with ocamlbuild ...

[ygrek]

Hi,

 Probably you are not calling ocamlbuild directly, but through make or shell script, so just put
 preprocessing step there to generate real myocamlbuild.ml

-- 
 

Re: [Caml-list] pre-process myocamlbuild.ml with ocamlbuild ...

[Pietro Abate]

On 30/06/15 11:03, ygrek wrote:
>  Probably you are not calling ocamlbuild directly, but through make or shell script, so just put
>  preprocessing step there to generate real myocamlbuild.ml

You are suggesting something along these lines : 

-------------- Makefile snippet

ocamlbuild:
  mkdir -p _build
  cp myocamlbuild.ml _build
  cd _build ; /usr/bin/ocamlopt.opt unix.cmxa -I /usr/lib/ocaml/ocamlbuild /usr/lib/ocaml/ocamlbuild/ocamlbuildlib.cmxa -pp "cppo -D OCAML4022" myocamlbuild.ml /usr/lib/ocaml/ocamlbuild/ocamlbuild.cmx -o myocamlbuild
  cd ..

OCAMLBUILD=_build/myocamlbuild

all: ocamlbuild 
  everything else ...

------------- Makefile snippet

Yes, your solution works, but it's extremely hackish ! 
I was hoping for something more clean. Is it possible to
accomplish this with ocamlbuild ?

p

Re: [Caml-list] pre-process myocamlbuild.ml with ocamlbuild ...

[ygrek]

On Tue, 30 Jun 2015 22:12:02 +0200
Pietro Abate <Pietro.Abate@pps.univ-paris-diderot.fr> wrote:

> On 30/06/15 11:03, ygrek wrote:
> >  Probably you are not calling ocamlbuild directly, but through make or shell script, so just put
> >  preprocessing step there to generate real myocamlbuild.ml
> 
> You are suggesting something along these lines : 

No, I thought of something like:

myocamlbuild.ml: myocamlbuild.ml.pp
  cppo $< -o $@

build: myocamlbuild.ml
  ocamlbuild ...

--