Re: oasis

[Sylvain Le Gall <sylvain@le-gall.net>]

On 27-11-2010, Anastasia Gornostaeva <ermine@ermine.pp.ru> wrote:
> On Sat, Nov 27, 2010 at 10:20:38AM +0000, Sylvain Le Gall wrote:
>> Hi,
>> 
>> On 26-11-2010, Anastasia Gornostaeva <ermine@ermine.pp.ru> wrote:
>> > Hello.
>> >
>> > How can I substitute in setup.ml (not in _oasis file) values for
>> > CCOpt and CCLib fields? I think it is better to substitute them from 
>> > setup.data, if I could to put proper values to setup.data.
>> > For example:
>> >   CCOpt: $freetype_ccopt
>> > and put to setup.data output of `freetype-config --clib` for field 
>> > freetype_ccopt.
>> 
>> As I answer you in private: there will be pkg-config support in 0.3.0.
>> This will solve this issue, at least.
>> (e.g. you will be able to define:
>> BuildDepends: freetype2 (pkg-config), oUnit, ...)
>
> Sorry, but i didnt receive your mail..

I resent it, but it doesn't contains the ultimate solution, just what I
said here.

> And pkg-config probably is not best solution on bsd and macosx systems because
> it does not guarante nothing.
> The best (and common) solution is CFLAGS and LIBS env variables. :-)
> Or this pkg-config will allow custom paths for those C librares that do not
> depend on pkg-config at concrete systems?
>
> [...]

My current state about this solution is:
- defines BuildDepends: freetype2 (pkg-config), to make clear that there
  is a C build-depends
- allow to override the defined variable freetype2_cflags and
  freetype2_libs. If they are both defined by user, don't even call
  pkg-config for this package

>
>> > I need a way to substitute paths.
>> >
>> 
>> A last solution, you can apply right now, is to override this call:
>> let () = setup ();;
>> (last line of setup.ml)
>> 
>> by 
>> 
>> let f pkg = 
>>   (* Call freetype-config and add flags where 
>>      needed in pkg
>>    *)
>>   ...
>> 
>> let () = BaseSetup.setup (f setup_t);;
>
> Interesting way. Thanks, I'll ckeck it right how.
>

As you state privately, this indeed has also problem because you also
need to do it in myocamlbuild.ml.

Here is a new proposal about this:
- use a PostConfigureCommand to invoke a shell script freetype2.sh
- in freetype2.sh invoke freetype-config and output flags in setup.data
  using "echo 'freetype2_cflags = "$output"' >> setup.data' and
  "echo 'freetype2_libs = "$output"' >> setup.data' 
- add in _tags a "src/toto.cma: pkg_config_freetype2" 
- add in myocamlbuild.ml a "tag [pkg_config_freetyp2; compile; ocaml] &
  [... (* load the content of freetyp2_cflags *) ... ]"

This is not simple but this is probably what I will do for the support
of C libraries in 0.3.0.

Regards,
Sylvain Le Gall