Re: [Chicken-users] ffi questions and bug (?)

[felix winkelmann]

On 5/19/05, Carlos Pita <address@hidden> wrote:
> 
> Just to get the feeling, can you give me a
> simple example of (manually) wrapping a
> trivial C++ class using the ffi and tinyclos
> (I mean "manually" without recurring to
> easy ffi or swig)?

You can simply use the `-debug F' option to chicken/csc
to see the code generated by the easy FFI:

% cat x.scm
(require-extension tinyclos)

#>!
class Foo {
  int x_;

public:
  Foo(int x) { x_ = x; }
  virtual ~Foo() {}

  int bar(int y) { return x_ * y; }
};
<#

(define f1 (make <Foo> 99))
(pp (bar f1 10))
(destroy f1)

% csc -c++ x.scm -debug F
(begin (declare (hide g2)) (define-class <Foo> (<c++-object>) ()))
(begin
  (define g2 (foreign-lambda void "delete " (pointer "Foo")))
  (define-method (destroy (this <Foo>)) (g2 (slot-ref this 'this))))
(begin
  (declare (hide g3))
  (define g3 (foreign-lambda (pointer "Foo") "new Foo" integer))
  (define-method
    (initialize (this <Foo>) initargs)
    (slot-set!
      this
      'this
      (if (and (pair? initargs) (eq? 'this (##sys#slot initargs 0)))
        (cadr initargs)
        (##sys#apply g3 initargs)))))
(begin
  (declare (hide g4))
  (define g4
    (foreign-lambda*
      integer
      (((pointer "Foo") g5) (integer g6))
      "return(g5->bar(g6));"))
  (define-method
    (bar (this <Foo>) . args)
    (##sys#apply g4 (slot-ref this 'this) args)))
% ./x
990

If you need more information, just ask.


cheers,
felix