Just to clarify it: I wrote a C function to add an attribute to an
object. It is called from scheme, and it needs w_current and o_current
pointers. I searched in the web, and now I found how to convert a
pointer to a SCM variable.
I would not want to change the behaviour of the hooks (they don't get
w_current and o_current as parameters), so I wonder if w_current and
o_current pointers could be passed to scheme as two variables, with
names __wcurrent, and __ocurrent (using scm_c_define).
These variables can be defined just before calling scm_run_hook.
I have tried this and it works fine: when you place a new pin, the
default attributes (pinlabel, pintype, pinnumber, and pinseq) are added
automatically. This is configurable in system-gschemrc file. However, I
leave it activated by default. Any thoughts/objections?
Would it be interesting to set __wcurrent and __ocurrent before calling
any other scm_run_hook function? (Just to standardize this way). I think
it would be better...
Thanks,
Carlos
P.D.: Ales, I suppose you want to wait a little time before making any
changes to CVS. Let me know when the CVS can be updated again.
El sáb, 28-01-2006 a las 23:24 +0100, Carlos Nieves Ónega escribió:
> Hi all,
> I'm thinking about adding some configurable default attributes to a
> newly placed pin.
> I thought about two options:
> - Option 1: Load a list with name,values of attributes to be added
> from the file gschemrc.
> - Option 2: Write an add-pin-hook function and do it in scheme.
>
> By now I like option 2, but my knowledge about C interfacing to scheme
> is limited, so I have some doubts...
>
> At the end of o_pin_end function I added:
>
> if (scm_hook_empty_p(add_pin_hook) == SCM_BOOL_F &&
> o_current != NULL) {
> scm_run_hook(add_pin_hook,
> scm_cons(g_make_attrib_smob_list(w_current, o_current),
> SCM_EOL));
> }
>
> so the new hook is run. As I understand, the first two parameters are
> w_current and o_current.
>
> The new hook is run, and if I put into gschemrc the following:
>
> (define (print-all-attributes attribute-list)
> (for-each (lambda (attribute) (display attribute)) attribute-list))
>
> (add-hook! add-pin-hook print-all-attributes)
>
> I get nothing printed: the attribute list is empty. This isn't
> surprising because by default, a pin has no attributes.
>
> Now I wrote a very basic (and untested) scheme function which calls to
> o_attrib_add_attrib:
>
> SCM
> g_add_attrib(SCM scm_wcurrent, SCM scm_object, SCM scm_newtext,
> SCM scm_vis, SCM scm_show)
> {
> TOPLEVEL *w_current = (TOPLEVEL *) SCM_SMOB_DATA(scm_wcurrent);
> OBJECT *object = (OBJECT *) SCM_SMOB_DATA (scm_object);
> int vis, show;
> gchar *newtext=SCM_STRING_CHARS(scm_newtext);
>
> vis = SCM_INUM(scm_vis);
> show = SCM_INUM(scm_show);
>
> o_attrib_add_attrib (w_current, newtext, vis, show, object);
>
> return SCM_BOOL_T;
>
> }
>
> This function is registered in g_register.nw as:
> scm_c_define_gsubr ("add-attribute-to-object", 5, 0, 0, g_add_attrib);
>
>
> I expect to be able to call this function inside the add-pin-hook
> function, just adding the new parameters. The problem is: how can I do
> it? if I try to print all the arguments to the add-pin-hook function, I
> get an empty list.
> Even if I do:
> (define (print-all-attributes attribute-list)
> (display "Parameter List length: ")
> (display (length attribute-list))
> (display ".\n")
> (for-each (lambda (attribute) (display attribute)) attribute-list))
> (add-hook! add-pin-hook print-all-attributes)
>
> It reports a 0 elements list. Where have w_current and o_current gone?
>
> Any ideas?. Thanks,
>
> Carlos
>
