Re: [Swig-devel] New ocaml module

[Camille G. <k10...@wa...>]

Le mardi 17 juillet 2012 00:10:10, William S Fulton a écrit :
> On 15/07/12 17:48, k1000 wrote:
> > Hello Swig developpers,
> > 
> > I've been using swig for a while, and have started to rewrite the ocaml
> > module, following a proposal made in 2009 by Guillaume Yziquel.
> 
> Do you have a link to this proposal?
> 
In the swig-devel archives, here is the first answer to his mail (which is 
also your answer by the way :-)) : 
http://sourceforge.net/mailarchive/message.php?msg_id=22889753
His also has a dedicated yziquel-ocaml branch in subversion.

> > Based on the D module code, my code supports non-overloaded classes,
> > functions and variables - everything statically typed.
> > 
> > In order to get working directors, I need to have a way to 'duplicate' a
> > 
> > class. Consider the following example.i :
> >> %module(directors=1) example;
> >> 
> >> %feature("director") foo;
> >> 
> >> %inline %{
> >> class foo {
> >> public:
> >> virtual int main();
> >> };
> > 
> > The trick would be to generate 2 ocaml classes : the plain "foo" director
> > class, which is meant to be derived in ocaml, and a "foo_cppderived"
> > pseudo- class, which wraps C++ derived implementations.
> > 
> > In generated .ml file, this would look like :
> >> class foo = object(this)
> >> method main = [[ explicit call to c++ "this->foo::main()" ]]
> >> end
> >> 
> >> class foo_cppderived = object(this)
> >> inherit foo
> >> method main = [[ virtual call to c++ "this->main()" ]]
> >> end
> > 
> > And used like that :
> >> class bar = object(this)
> >> inherit foo as super
> >> method main = 1 + super#main (* explicit upcall *)
> >> end
> > 
> > This trick is not ocaml specific, but would still have two advantages :
> > enforce override check at target language level (for pure virtual
> > functions), and get rid of having to select upcalls.
> 
> Hi Camille,
> 
> I'm afraid I don't know ocaml, so if you are proposing something for all
> other director classes, you'll have to provide a use case in one of the
> more mainstream languages.
> 
> I vaguely recall having two classes for one C++ class for either an
> early implementation of directors or early implementations of proxy
> classes. They have been long since scrapped. Searching through some
> commit logs or the CHANGES file might reveal why.
> 
> With regard to the Ocaml module in general, it is in dire need of a
> maintainer. I'll be surprised if it works very well atm. I gave up
> trying to get it to pass any tests a few years back.

Hello William,

I've looked at the CHANGES file and part of swig-devel archives, and no trace 
of duplicate classes. The first note from Mark Rose about directors already 
looks like actual implementation. I may investigate a bit more about this 
later. For now, I give priority to basic features, and overloading.

By the way, is there a way to create specific typemaps for "SWIGTYPE" being a 
class, or are we stuck with a global case ? The documentation gives a specific 
construct for enums, but none for structs/classes.
To be precise, I use different wrapping mechanism for class-type objects and 
non class-type objects, and I'd like to discriminate the cases at typemap 
level.

Camille