Re: Inheriting from foreign objects

[Andreas Rottmann]

Thien-Thi Nguyen <address@hidden> writes:

>    From: Neil Jerram <address@hidden>
>    Date: 10 Apr 2002 20:47:13 +0100
> 
>        Andreas> Is there a way I can cleanly derive from C-created classes?
> 
>    I'd say you're in virgin territory here, and that any advice you can
>    give on such problems, and on defining a C API for GOOPS, would be
>    very useful.
> 
> it looks like foreign bit is set when superclass list is empty.  perhaps
> a good guideline would be to use at least `(list <object>)' for `supers'
> for normal operation.  

I can't test your statement, since I have switched to create a
'normal' class and have a special slot being a smob containing the
pointer to the C++ object.

> btw, it doesn't look like user-supplied ctor/dtor
> are suppressed based on foreign bit in any case.
> 
When you inherit from a 'foreign' class, the constructor/destructor
fields of the new class are set NULL.

I suggest you write some 'test' code that uses the various
goops-related C functions, as that would both make them easier to
understand and they can be validated this way.

> [cc guile-user in order to ask survey question: which goops-related C
> functions do people use now?  the answer to this helps shape definition
> of the C interface to goops -- thanks!]
> 
I use, in my C++ <-> GOOPS bindings:

scm_load_goops()
scm_make()
scm_basic_make_class()
scm_sys_allocate_instance()
scm_sys_initialize_object()
scm_slot_set_x()
SCM_IS_A_P()
scm_add_method()
scm_generic_function_methods()
scm_method_procedure()
scm_method_specializers()
scm_slot_exists_p()
scm_slot_ref()

I may have overlooked some.

BTW: Has anybody of the developers looked at my GOOPS-related
bugreport yet? Since I have included a program documenting the bug it
shouldn't be too hard to investigate...

Regards, Andy
-- 
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