Re: [Caml-list] A C to OCaml helper ?

[Kuba Ober <ober.14@osu.edu>]

On Thursday 13 March 2008, Basile STARYNKEVITCH wrote:
> Fabrice Marchant wrote:
> > On Wed, 12 Mar 2008 22:03:51 +0100
> >
> > Basile STARYNKEVITCH <basile@starynkevitch.net> wrote:
> >> Fabrice Marchant wrote:
> >>> Please does it exist some tool that could do at least the very
> >>> mechanical first parts of the translation of a C source to OCaml ?
> >>
> >> Why do you want to do that?
> >
> > Why do I want a tool to do the _very mechanical parts_ of the job ?
> >   A simple example :
> > because I would be happy to get the comment brackets automatically
> > translated ( and the C++ like C extension // too.) There are several such
> > very automatic things like if( ) -> if then.
> >
> >> You could call most of your C routines from Ocaml.
> >
> >   Yes, but in the present case, I'm interesting in a full rewriting. This
> > is precisely because I imagine to be able to rewrite the C ( game )
> > program a very different and terse way, that I undertake this task.
> >
> >> And most importantly, the main interest of ocaml is the way of thinking
> >> it.
> >
> > Absolutely : that's the reason why I play to rewrite the C program an
> > OCaml way.
>
> Then you have to rewrite it manually, because you have to re design your
> program differently (in a functional way). In particular, functional
> values are very common in Ocaml, and do not exist as such in C (a C
> pointer function is *not* a closure, you have to bring it some data);
> and combining both is done manually: callbacks, signal & slots [like in
> QT or GTK], etc...
>
> Also, in Ocaml you frequently have tiny functions : just look at how
> easily you can sort an array of records of person's first & last names
> in Ocaml (it really fits in one or two lines), and how it become harder
> in C.
>
>  >  However, I remember you are the man who oriented me to OCaml and I'm
>  > very grateful of this, because OCaml programming is a real pleasure
>
> So you learnt that Ocaml programming paradigms are different from those
> in C.
>
> I'm really not convinced that any automatic tool could bring you
> something valuable. Because tools do not help to re design (not only
> refactor or translate) programs.
>
> And my advice is even to avoid doing any immediate translation by hand.
> Do not look often at your C code, but redesign your game (and your
> former experience in C game coding would help you). Perhaps this could
> be done incrementally, by keeping some routines in C (and calling them
> from Ocaml).

I disagree somewhat. A good starting point is to have mechanically-translated
code that works, and then work on refactoring it to utilize what OCaml has to
offer.

In fact, C++ may provide much better translation results than C, since, if
properly written, the C++ sources will utilize higher-level primitives that
look better in OCaml. C is a really primitive language, by OCaml's 
standards ;)

Cheers, Kuba