GOOPS bug found?

* GOOPS bug found?
@ 2002-04-17 19:35 Andreas Rottmann
  0 siblings, 0 replies; 4+ messages in thread
From: Andreas Rottmann @ 2002-04-17 19:35 UTC (permalink / raw)

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Hi!

[Note: this bug refers to Guile 1.7.0 from CVS, only some days old]

As my C++ <-> Guile bindings (ucxx.sf.net) are approaching
completeness, I have run into another strange problem. I have managed
to isolate the code that causes it and wrote a self-contained C
program that exposes the bug. 

Here is what I do:

1) I create a new class, containing one slot using
   scm_basic_create_class().

2) I then add a method to 'initialize', specialized for the newly
   created class, that calls a C function.

3) I create a new class, inheriting from the C-created class, and
   instantiate one object of the new class (using make).

4) I do (define-method (initialize (obj <new-class>) initargs) (next-method)).
   This expression leads to this:

   ERROR: In procedure struct-ref:
   ERROR: Wrong type argument in position 1 (expecting STRUCTP): ()

A backtrace (using my original code) is attached, but you should
easily be able to reproduce and investigate this strange behaviour
using the attached C program.

I hope someone can shed light on this strange thing...

Regards, Andy

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[-- Attachment #2: bug.c --]
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#include <stdio.h>

#include <libguile.h>

static SCM my_constructor(SCM obj, SCM initargs)
{
  printf("constructor called!\n");
  scm_slot_set_x(obj, scm_str2symbol("a-slot"), SCM_BOOL_T);

  return obj;
}

static void set_constructor(SCM klass, SCM (*proc)(SCM, SCM))
{
  SCM initialize = scm_variable_ref(
          scm_c_module_lookup(scm_module_goops, "initialize"));
  SCM sym_obj = scm_str2symbol("obj");
  SCM sym_args = scm_str2symbol("args");
  SCM constr = scm_c_make_gsubr("constructor", 1, 0, 1, proc);
  SCM constrm = scm_closure(scm_list_2(scm_list_2(sym_obj, sym_args),
                                       scm_list_3(constr, sym_obj, sym_args)),
                            SCM_EOL);
  SCM meth = scm_make(scm_list_5(scm_class_method,
                                scm_c_make_keyword("specializers"),
                                scm_list_2(klass, scm_class_top),
                                scm_c_make_keyword("procedure"),
                                constrm));

  scm_add_method(initialize, meth);
}

static void real_main(void *closure, int argc, char *argv[])
{
  SCM klass, slots;

  scm_load_goops();

  slots = scm_list_1(scm_list_3(scm_str2symbol("a-slot"),
                                scm_c_make_keyword("init-value"),
                                SCM_BOOL_F));
  klass = scm_basic_make_class(scm_class_class, scm_makfrom0str("<my-object>"),
                               scm_list_1(scm_class_object),
                               slots);
  set_constructor(klass, my_constructor);

  scm_c_define("<my-object>", klass);

  scm_c_eval_string("(use-modules (oop goops))");
  scm_c_eval_string("(define-class <new-object> (<my-object>))");
  scm_c_eval_string("(make <new-object>)");

  // this produces the error
  scm_c_eval_string("(define-method (initialize (obj <new-object>) initargs)"
                    "  (next-method))");
}

int main(int argc, char *argv[])
{
  scm_boot_guile(argc, argv, real_main, NULL);

  return 0;
}

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-- 
Andreas Rottmann         | Dru@ICQ        | 118634484@ICQ | a.rottmann@gmx.at
http://www.8ung.at/rotty | GnuPG Key: http://www.8ung.at/rotty/gpg.asc
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