tr_delay.h

/* File:      tr_delay.h
** Author(s): Kostis Sagonas, Baoqiu Cui
** Contact:   xsb-contact@cs.sunysb.edu
** 
** Copyright (C) The Research Foundation of SUNY, 1986, 1993-1998
** 
** XSB is free software; you can redistribute it and/or modify it under the
** terms of the GNU Library General Public License as published by the Free
** Software Foundation; either version 2 of the License, or (at your option)
** any later version.
** 
** XSB is distributed in the hope that it will be useful, but WITHOUT ANY
** WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
** FOR A PARTICULAR PURPOSE.  See the GNU Library General Public License for
** more details.
** 
** You should have received a copy of the GNU Library General Public License
** along with XSB; if not, write to the Free Software Foundation,
** Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** $Id: tr_delay.h,v 1.16 2005/01/14 18:31:35 ruim Exp $
** 
*/


/* special debug includes */
#include "debugs/debug_delay.h"

/*----- Stuff for trie instructions ------------------------------------*/

/*
 * In the execution of trie code, handle_conditional_answers is called
 * (in proceed_lpcreg) when NodePtr is an answer leaf.  If the answer is
 * a conditional one, then call delay_positively() to put it into the
 * delay list of the parent predicate.
 *
 * After the execution of trie code, the substitution factor of the
 * _answer_ is stored in array var_regs[], and the number of variables is
 * saved in num_vars_in_var_regs (-1 means there is no variable, 0 means
 * there is one variable, ...)
 *
 * Instead of saving the substitution factor of the call, we can save
 * the substitution factor of the answer in the delay element.
 */

#ifndef IGNORE_DELAYVAR
#define handle_conditional_answers {                                    \
    CPtr temp_hreg;                                                     \
    VariantSF subgoal;                                                  \
                                                                        \
    if (is_conditional_answer(NodePtr)) {                               \
      xsb_dbgmsg((LOG_DELAY,                                             \
                 "Trie-Code returning a conditional answer for "));     \
      subgoal = asi_subgoal(Delay(NodePtr));                            \
      dbg_print_subgoal(LOG_DELAY, stddbg, subgoal);                    \
      xsb_dbgmsg((LOG_DELAY, " (positively delaying)\n"));              \
      xsb_dbgmsg((LOG_DELAY,                                             \
                      ">>>> In handle_conditional_answers macro: \n"));  \
      xsb_dbgmsg((LOG_DELAY, ">>>>     num_vars_in_var_regs = %d\n",     \
                      num_vars_in_var_regs));                           \
      if (num_vars_in_var_regs == -1) {                                 \
        delay_positively(subgoal, NodePtr,                              \
                         makestring(get_ret_string()));                 \
      }                                                                 \
      else {                                                            \
        /* create the answer subsf ret/n */                             \
        temp_hreg = hreg;                                               \
        new_heap_functor(hreg, get_ret_psc(num_vars_in_var_regs + 1));  \
        {                                                               \
          int i;                                                        \
          for (i = 0; i < num_vars_in_var_regs + 1; i++) {              \
            cell(hreg++) = (Cell) var_regs[i]; /* new */                \
            xsb_dbgmsg((LOG_DELAY, ">>>>     var_regs[%d] = ", i));     \
            dbg_printterm(LOG_DELAY, stddbg, cell(var_regs[i]), 25);    \
            xsb_dbgmsg((LOG_DELAY, "\n"));                              \
          }                                                             \
        }                                                               \
        delay_positively(subgoal, NodePtr, makecs(temp_hreg));          \
      }                                                                 \
    }                                                                   \
  }
#else  /* IGNORE_DELAYVAR */
#define handle_conditional_answers {                    \
  if (is_conditional_answer(NodePtr)) {                 \
    VariantSF subgoal = asi_subgoal(Delay(NodePtr));    \
    delay_positively(subgoal, NodePtr,                  \
                     makestring(get_ret_string()));     \
  }                                                     \
}
#endif /* IGNORE_DELAYVAR */

/*---------------------- end of file tr_delay.h ------------------------*/

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