24 SWIG and MzScheme

Creating native MzScheme structures

This section contains information on SWIG's support of MzScheme.

24.1 Creating native MzScheme structures

Example interface file:

/* define a macro for the struct creation */
%define handle_ptr(TYPE,NAME)
%typemap(argout) TYPE *NAME{
    Scheme_Object *o = SWIG_NewStructFromPtr($1, $*1_mangle);
    SWIG_APPEND_VALUE(o);
}

%typemap(in,numinputs=0) TYPE *NAME (TYPE temp) {
    $1 = &temp;
}
%enddef

/* setup the typemaps for the pointer to an output parameter cntrs */
handle_ptr(struct diag_cntrs, cntrs);

Then in scheme, you can use regular struct access procedures like

	; suppose a function created a struct foo as 
	; (define foo (make-diag-cntrs (#x1 #x2 #x3) (make-inspector))
	; Then you can do
	(format "0x~x" (diag-cntrs-field1 foo))
	(format "0x~x" (diag-cntrs-field2 foo))
	;etc...

That's pretty much it. It works with nested structs as well.