Re: [Caml-list] oasis building out-of-src and camlp4

[Gabriel Scherer <gabriel.scherer@gmail.com>]

Thanks for the reproducible information. I just tried and could
reproduce the issue.

The problem comes from the fact that, with the command-line invocation
you use oasis generates the build description files (_tags,
myocamlbuild.ml, setup.data) in the build directory, not in the source
directory, but ocamlbuild when invoked (from the source directory)
will look for them in the source directory. In particular, I could
"fix" the build by doing

  ...
  ocaml setup.ml -C $PWD/../oasis-camlp4 -configure
  for f in {myocamlbuild.ml,_tags,setup.data}; do ln -s $PWD/$f
../oasis-camlp4; done
  ocaml setup.ml -C $PWD/../oasis-camlp4 -build -build-dir $PWD/build

It looks like oasis's behavior with "-C $DIR -configure" is
problematic: it should generate its files in $DIR -- except maybe
setup.ml, or then people would have to run (ocaml $DIR/setup.ml -C
$DIR ...).

TL;DR: this appear to be an oasis issue, rather than a issue with
CMake or ocamlbuild.

On Wed, Sep 23, 2015 at 10:19 AM, Magnus Therning <magnus@therning.org> wrote:
> On Wed, Sep 23, 2015 at 09:48:43AM +0200, Anil Madhavapeddy wrote:
>> On 22 Sep 2015, at 23:12, Magnus Therning <magnus@therning.org> wrote:
>> >
>> > ~~~
>> > + /usr/bin/ocamldep.opt -modules src/main.ml > src/main.ml.depends
>> > File "src/main.ml", line 12, characters 4-8:
>> > Error: Syntax error
>> > Command exited with code 2.
>> > Compilation unsuccessful after building 1 target (0 cached) in 00:00:00.
>> > E: Failure("Command ''/usr/bin/ocamlbuild' src/main.byte -tag debug -build-dir /home/magnus/devo/tmp/oasis-camlp4-build/build' terminated with error code 10")
>> > ~~~
>> >
>> > What am I missing here, how do I get the second example to build?
>>
>> The ocamldep invocation here is not passing the -pp parameter to run
>> the source code through camlp4.  I'm not sure how you fix that in
>> CMake, but add the relevant lines (which should be the same as those
>> passed to ocamlc/ocamlopt) to ocamldep and it should get further...
>
> Ah, OK, I'll have to look into that.
>
> I should point out though that I've not started using CMake yet.  The
> examples I showed use just `oasis` (with `ocamlbuild` as its tool).  I'm
> still trying to work out the incantations to use, the integration with
> CMake comes later :)
>
> /M
>
> --
> Magnus Therning                      OpenPGP: 0xAB4DFBA4
> email: magnus@therning.org   jabber: magnus@therning.org
> twitter: magthe               http://therning.org/magnus
>
> LeBlanc's law: Later equals never.