Re: ffi-helper: status

[Matt Wette <matt.wette@gmail.com>]

> On Jul 7, 2017, at 5:31 PM, Matt Wette <matt.wette@gmail.com> wrote:
> 
> 
>> On Jul 7, 2017, at 5:18 PM, Matt Wette <matt.wette@gmail.com> wrote:
>> However, the above generates 397 FFI declarations into a cairo.scm file which is about 6000 lines long.  I’m not 
>> sure if I want to start testing this code or start converting suggestions and have guile-users do some testing.  
> 
> That is, for this example, I no longer run into declarations which my code says “failed,” indicating that it didn’t know what to do with the declaration.
> 
> I already notice that the function types converters should be called “unwrap” and that they should be called by the procedure interface.  I am going to start playing with cairo_set_user_data to see if passed procedures work. 

Another working demo:

mwette$ guile exam.d/cairo02.scm
d1 called with ((abc . 123) (def . 456))

mwette$ cat exam.d/cairo02.scm
;; exam.d/cairo02.scm

(use-modules (cairo cairo))		; auto-generated from cairo.h etc
(use-modules (ffi-help-rt))		; pointer-to
(use-modules (system foreign))		; string->pointer, pointer<->scm

(define srf (cairo_svg_surface_create (string->pointer "abc.svg") 200.0 200.0))
(define cr (cairo_create srf))

;; typedef struct _cairo_user_data_key {
;;   int unused;
;; } cairo_user_data_key_t;
;;
;; typedef void (*cairo_destroy_func_t)(void *data);
;;
;; cairo_status_t cairo_set_user_data(cairo_t *cr, const cairo_user_data_key_t
;;      *key, void *user_data, cairo_destroy_func_t destroy);

(define k1 (make-cairo_user_data_key_t)) ; make a key
(define v1 '((abc . 123) (def . 456)))	 ; make some data
(define (d1 data)			 ; callback
  (simple-format #t "d1 called with ~S\n" (pointer->scm data)))
	 
(cairo_set_user_data cr (pointer-to k1) (scm->pointer v1) d1)

(cairo_destroy cr)
(cairo_surface_destroy srf)

;; --- last line ---