Ejemplo n.º 1
0
/*-------------------------------------------------------------------------*
 * PL_CALL_PROLOG                                                          *
 *                                                                         *
 * Call_Prolog runs the execution of one prolog goal.                      *
 * The current choice point is updated to set ALTB to Call_Prolog_Fail and *
 * CP is set to Call_Prolog_Success. At the end ALTB and CP are restored.  *
 * To ensure that a choice point always exists before invoking Call_Prolog,*
 * Start_Prolog reserve the space for a feint choice point, i.e ALTB can be*
 * safely modified.                                                        *
 *                                                                         *
 * Call_Prolog returns TRUE if the predicate has succeed, FALSE otherwise. *
 * The called predicate can be non-deterministic.                          *
 *-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog(CodePtr codep)
{
  WamWord *query_b = B;
  WamCont save_CP = CP;
  WamCont save_ALTB = ALTB(query_b);
  Bool ok;

  ALTB(query_b) = (CodePtr) Call_Prolog_Fail;	/* modify choice point */

  CP = Adjust_CP(Call_Prolog_Success);

#if defined(_WIN32) || defined(__CYGWIN__)
  SEH_PUSH(Win32_SEH_Handler);
#endif
  ok = Call_Next(codep);
#if defined(_WIN32) || defined(__CYGWIN__)
  SEH_POP;
#endif

  CP = save_CP;			/* restore continuation */
  ALTB(query_b) = save_ALTB;	/* restore choice point */

  return ok;
}
Ejemplo n.º 2
0
void
test_jump_and_c_ret(void)
{
  printf("jump/c_ret...\n");
  ALTB(B) = (WamCont) error;
  Init_CP(error);
  ma_test_jump_and_c_ret();
}
Ejemplo n.º 3
0
/*-------------------------------------------------------------------------*
 * PL_CALL_PROLOG_NEXT_SOL                                                 *
 *                                                                         *
 * Call_Prolog_Next_Sol bactracks over the next solution.                  *
 *-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog_Next_Sol(WamWord *query_b)
{
  WamCont save_CP = CP;
  WamCont save_ALTB = ALTB(query_b);
  Bool ok;

  ALTB(query_b) = (CodePtr) Call_Prolog_Fail;	/* modify choice point */

  CP = Adjust_CP(Call_Prolog_Success);	/* should be useless since */
  /* alternative will restore CP */

  ok = Call_Next(ALTB(B));

  CP = save_CP;			/* restore continuation */
  ALTB(query_b) = save_ALTB;	/* restore choice point */

  return ok;
}
Ejemplo n.º 4
0
/*-------------------------------------------------------------------------*
 * PL_CALL_PROLOG                                                          *
 *                                                                         *
 * Call_Prolog runs the execution of one prolog goal.                      *
 * The current choice point is updated to set ALTB to Call_Prolog_Fail and *
 * CP is set to Call_Prolog_Success. At the end ALTB and CP are restored.  *
 * To ensure that a choice point always exists before invoking Call_Prolog,*
 * Start_Prolog reserve the space for a feint choice point, i.e ALTB can be*
 * safely modified.                                                        *
 *                                                                         *
 * Call_Prolog returns TRUE if the predicate has succeed, FALSE otherwise. *
 * The called predicate can be non-deterministic.                          *
 *-------------------------------------------------------------------------*/
Bool
Pl_Call_Prolog(CodePtr codep)
{
  WamWord *query_b = B;
  WamCont save_CP = CP;
  WamCont save_ALTB = ALTB(query_b);
  Bool ok;

  ALTB(query_b) = (CodePtr) Call_Prolog_Fail;   /* modify choice point */

  CP = Adjust_CP(Call_Prolog_Success);

  ok = Call_Next(codep);

  CP = save_CP;                 /* restore continuation */
  ALTB(query_b) = save_ALTB;    /* restore choice point */

  return ok;
}
Ejemplo n.º 5
0
void
test_switch_ret(void)
{
  printf("call_c()+switch_ret...\n");

  ALTB(B) = (WamCont) error;
  for (i = 0; swt[i] >= 0; i++)
    Call_Pl(ma_test_switch_ret, 1);

  Call_Pl(ma_test_switch_ret, 0);	/* here swt[i]= -1 switch should fail */
}
Ejemplo n.º 6
0
/*-------------------------------------------------------------------------*
 * PL_QUERY_END                                                            *
 *                                                                         *
 *-------------------------------------------------------------------------*/
void
Pl_Query_End(int op)
{
  WamWord *query_b, *prev_b, *b;
  Bool recoverable;


  if (query_stack_top == query_stack)
    Pl_Fatal_Error("Pl_Query_End() but no query remaining");

  query_b = *--query_stack_top;
  pl_query_top_b = query_stack_top[-1];

  recoverable =
    (ALTB(query_b) == Prolog_Predicate(PL_QUERY_RECOVER_ALT, 0));
  prev_b = BB(query_b);

  switch (op)
    {
    case PL_RECOVER:
      Assign_B(query_b);
      if (!recoverable)
	Pl_Fatal_Error("Pl_Query_End(PL_RECOVER) but unrecoverable query");

      Pl_Delete_Choice_Point(0);	/* remove recover chc-point */
      break;

    case PL_CUT:
      Assign_B((recoverable) ? prev_b : query_b);
      break;

    default:			/* case PL_KEEP_FOR_PROLOG */
      if (recoverable)
	{
	  if (B == query_b)
	    Assign_B(prev_b);
	  else
	    for (b = B; b > query_b; b = BB(b))	/* unlink recover chc-point */
	      if (BB(b) == query_b)
		BB(b) = prev_b;
	}
      Pl_Keep_Rest_For_Prolog(query_b);
    }
}
Ejemplo n.º 7
0
void
TRANS_pl_fail()
{
  M_Indirect_Goto(ALTB(B));
}