On 03/03/2015 15:55, Gerd Stolpmann wrote:
> Am Dienstag, den 03.03.2015, 14:15 +0100 schrieb François Bobot:
>> Gerd, do you think that something that does that could be added to ocamlfind? One tricky thing is to
>> know the library statically linked (ie. `Ocsigen_config.builtin_packages`), perhaps ocamlfind can
>> during linking add this information.
>
> I think so. For toploops, there is already code that tracks libraries
> already linked into the executable (i.e. if you ocamlmktop your
> toploop).

All was already in place indeed! It was easy to add. I kept caml-list in CC for discussing the big 
picture in order to get comments from people. Is mail still your preferred way of receiving patch?

I kept it simple, no hack (no automatic: cmxa -> cmxs) because I prefer problems in library META to 
be found than to be paper over.

The first patch adds:
- A library `findlib.dynlink` that depends on `findlib` and `dynlink`
- During linking (using `ocamlfind ocaml*`) if `-package findlib.dynlink` and `-linkpkg` are used 
then a module `Findlib_initl...` is linked after all packages and it stores the names of packages 
linked in `Findlib.linked_packages`.
- In the main program `Fl_dynlink.load_packages ["yojson"]` can be used to dynlink packages

The second patch forbids to run `Fl_dynlink.load_packages` during the initialization of packages 
(statically or dynamically linked), because `Findlib_initl...` is not yet run and because if you 
want to load a package that depend on a statically linked package not yet initialized, there is no 
sane semantic.

Problems:
- The package is named `findlib.dynlink`, the archive `findlib_dynlink.cm*` and the module 
`Fl_dynlink` ...
- If you don't use `-linkall` static packages could only be partially linked, and you can't link the 
remaining part later. So perhaps `-linkall` must be automatically added if `findlib.dynlink` is used.
- If you define `archive(native)` and not `archive(native,plugin)` the error is not nice (in 
Dynlink.Error). Perhaps I should add a `Package_not_dynamically_loadable of string` error, that 
should catch the loading of something else than `*.cmxs`.
- Often you link your binary with your own library without using `-package` (the library is not yet 
installed), and plugins for your tools depend on your library. Currently you should do before any 
`Fl_dynlink.load_packages`: `Findlib.linked_packages := "mylib"::Findlib.linked_packages`. For 
simplicity, I don't know if I should add a function `Fl_dynlink.add_linked_packages`, or an option 
to ocamlfind `-additional-package-statically-linked `.
- During the initialization of your own library (linked without -package) you should not use 
`Fl_dynlink.load_packages`, but the library doesn't protect you against this error.

Choices:
- If you don't link with `findlib.dynlink` or use `create_toploop`, the variables 
`Findlib.linked_packages` and `Findlib.linked_predicates` are empty because I don't wanted to add 
backward change by adding `Findlib_initl...` when `findlib` is linked.


Remains to do:
- Fix problems
- Documentations (add `plugin` in the list of standard predicates, ...)


Gerg, what do you think of this first version of the patch? Of the way to fix the problems?

Thanks,

Regards,

-- 
François