On Tue, 17 Jun 2003 09:07:06 +0100
Alastair Reid <[EMAIL PROTECTED]> wrote:
> On Tuesday 17 June 2003 2:33 am, Abraham Egnor wrote:
> > I'd like to make a haskell binding for a C++ library. Most of the
> > tools out there seem oriented towards c bindings, so it looks like
> > I'll be writing the FFI code generator myself. While I'm at it I
> > figure I might as well just make a general C++ binding tool. I've
> > been thinking about this, and I'd like some feedback on the ideas
> > I've had.
>
> All previous interfaces to C++ libraries that I know of have been
> created by writing a bunch of wrapper functions with C-style types
> like these wrapper for a virtual function 'foo'.
>
> void foo_T(S x) { x->foo(); }
> void foo_T(T x) { x->foo(); }
> void foo_T(U x) { x->foo(); }
>
> [Note that these are C++ functions but that their type is one that C
> programs can call.]
I'm assuming you don't want overloading here as these aren't functions
that can be called in C (or C99?).
>
> People have shied away from trying to create a more direct interface
> because:
>
> 1) C++ is a huge language (with the complexity mostly in types,
> classes and templates where you can't easily avoid them) and it seems
> that to be able to cope with any reasonable number of C++ libraries,
> you'd have to implement a large part of that language.
>
> 2) C++'s type/ class system is quite different from Haskell's class
> system. Any mapping of on to the other is likely to fall apart rather
> quickly.
If the code you are interfacing to doesn't make too much use of
templates then you can do what I did and hack together a SWIG module to
flatten the C++ to C (I had hoped that that would already be available
as it effectively does that anyways but I couldn't find it).
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