Re: ocamlbuild documentation (was Re: [Caml-list] Re: [ANN] OCaml Batteries Included, alpha 3)

[DooMeeR <d@doomeer.com>]

I'll skip over the documentation questions because people are beginning 
to say that I troll too much :p

> Instead, I found that ocamlbuild replaces my current build option of choice:
> 
>   ocamlopt foo.ml -I +lablGL lablgl.cmxa lablglut.cmxa foo.ml -o foo
> 
> with lots of incidental complexity:
> 
> $ cat myocamlbuild.ml
> open Ocamlbuild_plugin;;
> open Command;;
> 
> dispatch begin function
> | After_rules ->
>     ocaml_lib ~extern:true ~dir:"+lablGL" "lablgl";
>     ocaml_lib ~extern:true ~dir:"+lablGL" "lablglut";
> | _ -> ()
> end;;
> 
> $ cat _tags
> <main.{byte,native}>: use_lablgl, use_lablglut
> <**/*.ml>: use_lablgl
> 
> $ ocamlbuild foo.native

This is, indeed, and in my opinion, one of the BIGGEST problem with 
Ocamlbuild right now. In fact you didn't chose the easiest solution, 
which is:

ocamlbuild -cflags -I,+lablGL -lflags -I,+lablGL -lib lablgl -lib 
lablglut foo.native

However, this is of course very hackish, not documented (took me a while 
to figure that this was the simplest way of using a library), and still 
not satisfying at all. The extension of Ocamlbuild I am working on 
should allow you to replace this by:

ocamlbuild -pkg lablGL.glut foo.native

(the package lablGL.glut depends on the package lablGL, which will thus 
be included automatically)

I will work on an extension to allow tags such as use_pkg(lablGL.glut) 
to put this in a _tag file if you get tired of using the command line 
option.

This will require findlib though. If you do not have findlib, another 
solution I may implement someday would be:

ocamlbuild -libs +lablGL/lablgl,+lablGL/lablglut foo.native

Which is still better than the solution using ocamlopt directly IMO 
(because here, ocamlbuild can at least guess whether it should include 
the .cmxa or the .cma).

Now, I don't think it will happen someday that Ocamlbuild will be able 
to guess that lablGL should be included. It raises too many questions :(

-- 
Romain Bardou