[Caml-list] Working on dependent projects with ocamlbuild
Daniel Bünzli
Somewhat related to the discussion we had about the (bad) idea of
embedding dependencies into projects. I'd like to share the following
setup with ocamlbuild that allows me to work simultaneously on a
'base' project and two independent projects 'p1' and 'p2' that use
'base'. Basically my sources are distributed as follows :
base/src
p1/src
p2/src
What I used to do is to build a .cma out of the sources in base/src
and point the others to that .cma. When I did a change in base, I had
to build that .cma again, sometimes forgetting and seeking for bugs
in code while it was just a .cma freshness issue.
What I do now is that I completly forget about .cma's. I just create
the following links in p1 and p2
ln -s ../base/src p1/base
ln -s ../base/src p2/base
And add the following to their _tags file :
echo "<base>: include" >> p1/_tags
echo "<base>: include" >> p2/_tags
The rest is simply sorted out by ocamlbuild. Whenever I do a change
in base/src I don't need to recompile anything there, if I rework in
p1 or p2 things are automatically updated, I always use the latest
version of base's code. Of course this means longer build time when
you ocamlbuild -clean in p1 and p2 since they each build their own
version of base. But on the scale at which I work it is currently not
an issue.
The only caveat (that may disappear in the future) is that base/src
should be able to build without a plugin. Otherwise you will
have to integrate base's myocamlbuild.ml instructions into p1 and
p2's myocamlbuild.ml (btw. couldn't we find a less egoistic name for
that file). But if you are only working with _tagged caml sources it
should works perfectly, put your tags for base in base/src/_tags.
Best,
Daniel
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Matthieu Dubuget
>
> ln -s ../base/src p1/base
> ln -s ../base/src p2/base
Interesting.
One problem is that this solution is not usable with all kind of filesystem.
Salutations
Matt
Nicolas Pouillard
> Hello,
Hello,
Right. Multiple plugins should be the next new big feature of ocamlbuild.
The myocamlbuild.ml is egoistic, but is there to insist on the fact that your
are customizing the tool and not giving him full instructions/recipes. What
about ocamlbuildrc.ml?
However this setup definitely needs to go on the wiki.
Would you mind adding it?
Cheers,
--
Nicolas Pouillard aka Ertai
Daniel Bünzli
I'm now trying to do something a little bit more complex but fail to
solve it in the simple way I mentionned (maybe it is not possible). I
still have the same setup of two independent projects each depending
on a base project.
base/src
p1/src
p2/src
The base project is structured as follows :
base/src/a.ml
base/src/b.ml
base/src/base.ml
base/src/base.mli
with base.ml as follows
module A = A
module B = B
val ...
The idea is that b.ml can access things in a.ml that users of the
base project should not access. What I used to do is to
appropriatlely constrain the signatures of A and B in base.mli and
then create in a directory :
dest/base.cma (containing a.cmo b.cmo base.cmo)
dest/base.cmi
dest/base.mli
Thus forcing access to A and B via the constrained signature Base.A
and Base.B.
But if I use the approach mentionned in my initial posting users of
base will see the unconstrained a.cmi and b.cmi. Is there a way that
allows me to use this approach while maintaining the abstraction I
get with cma's ? Even if it means plugins in p1 and p2 ? I have the
impression that the response is negative because even if I try to
build a .cma with a mllib the build directory with have all .cmi and
the compilers will look at them.
Thanks for your answers,
Daniel Bünzli
Le 1 nov. 07 à 11:53, Daniel Bünzli a écrit :
> The base project is structured as follows :
>
> base/src/a.ml
> base/src/b.ml
> base/src/base.ml
> base/src/base.mli
Actually, if the emacs mode had a code-folding mode (module folding
to be precise) I'd seriously consider the option of writing all the
code in base.ml. Which would solve my problem while retaining the
convenience of the initial symlink solution.
Nicolas Pouillard
> Hello,
Hello,
[...]
> But if I use the approach mentionned in my initial posting users of
> base will see the unconstrained a.cmi and b.cmi. Is there a way that
> allows me to use this approach while maintaining the abstraction I
> get with cma's ? Even if it means plugins in p1 and p2 ? I have the
> impression that the response is negative because even if I try to
> build a .cma with a mllib the build directory with have all .cmi and
> the compilers will look at them.
There is a solution to specify directory scoping in a fine-grained manner.
This way you can explain precisely which directory is seen by a directory.
This is done in a plugin using the function Pathname.define_context that
takes a directory (an implicit pathname starting from the root of your
project) and a list of directories seen by it.
You can then setup your sources in order to confine some files in a directory
only seen by the modules that wrap them.
p1/src/implem/a.ml
p1/src/implem/b.ml
p1/src/base.ml
p1/myocamlbuild.ml
in p1/myocamlbuild.ml...
open Ocamlbuild_pack;;
dispatch begin function
| After_rules ->
Pathname.define_context "src" ["src/implem"]
| _ -> ()
end;;
HTH,
--
Nicolas Pouillard aka Ertai
_______________________________________________
Daniel Bünzli
Le 2 nov. 07 à 16:32, Nicolas Pouillard a écrit :
> There is a solution to specify directory scoping in a fine-
> grained manner.
Thanks, works as advertised. All the information of this thread is
now on the wiki :
http://brion.inria.fr/gallium/index.php/
Working_on_dependent_projects_with_ocamlbuild
I also added classical build errors that are reported differently
when ocamlbuild is used :
http://brion.inria.fr/gallium/index.php/New_kinds_of_build_errors
Best,
Daniel
Nicolas Pouillard
>
> Le 2 nov. 07 à 16:32, Nicolas Pouillard a écrit :
>
> > There is a solution to specify directory scoping in a fine-
> > grained manner.
>
> Thanks, works as advertised. All the information of this thread is
> now on the wiki :
>
> http://brion.inria.fr/gallium/index.php/
> Working_on_dependent_projects_with_ocamlbuild
>
> I also added classical build errors that are reported differently
> when ocamlbuild is used :
>
> http://brion.inria.fr/gallium/index.php/New_kinds_of_build_errors
Great, thanks!
--
Nicolas Pouillard aka Ertai
_______________________________________________