Re: [Chicken-users] A more detailed plea for help with FFI...

[Ed Watkeys]

On Dec 15, 2004, at 3:28 AM, Joel Reymont wrote:

> > Ed Watkeys wrote:
>
> > This is something, suprisingly, has been far easier to deal with in
> > Gambit than in Chicken. In Gambit (4.0b11), I can do something like
> > this:
>
> Ed, ever considered SWIG?
>
> I have had nothing but success with it in trying to wrap RakNet, 
> GuiChan
> and SDL ;-). Some fixes had to be made to SWIG itself but John Lenz 
> (the
> Chicken module maintainer) has been fantastic in his support.

Ideally, I would like to be able to use SWIG, but consider the 
following from the SWIG documentation:

17.8 Unsupported features and known problems
        *       No exception handling.
        *       No director support.
        *       No support for c++ standard types like std::vector.
	* 	No support for automatic garbage collection of wrapped classes and  
structures. (Planned on adding in SWIG version 1.3.25)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	* 	Importing multiple SWIG modules not working with TinyCLOS. (Planned 
 on fixing for 1.3.25)
	* 	Problems with complicated function overloading. (Planned on fixing  
for 1.3.25)

This is not acceptable to me: I do not want resource management to be 
the responsibility of my users i.e. Scheme programmers. I don't know 
when 1.3.25 is coming out and if these fixes are still planned to be in 
it. That said, I'm going to play with SWIG a bit and see how well it 
works.

For what I'm working on -- a wrapper for Core Graphics under OS X, it 
would definitely be nice to be to be able to use the same code to 
general libraries for Python, Perl, Tcl, Scheme, etc.

(I know, there's already a wrapper for Python, but Apple hasn't 
released the module definition. And I'd like an interface that is 
pretty much an exact translation of the Core Graphics API, so I can 
read Apple's documentation, mentally translate 
"CGBitmapContextAddLines" to "cg-bitmap-context:add-lines" and write 
working Scheme code. Apple's Core Graphics library for Python is 
different -- and incomplete -- enough to drive you crazy looking for 
functions that may or may not exist.)

Regards,
Ed