retract.c

VC嵌入式CLips专家系统,实现战场环境的目标识别

         /*==============================================*/

         if (theJoin->ruleToActivate != NULL)
           { AddActivation(theEnv,theJoin->ruleToActivate,theLHS); }

         /*=======================================================*/
         /* Send the partial match to the list of joins following */
         /* this join. If we're in the middle of a retract, add   */
         /* the partial match to the list of join activities that */
         /* need to be processed later. If we're doing an assert, */
         /* then the join activity can be processed immediately.  */
         /*=======================================================*/

         listOfJoins = theJoin->nextLevel;
         if (listOfJoins != NULL)
           {
            if (((struct joinNode *) (listOfJoins->rightSideEntryStructure)) == theJoin)
              { NetworkAssert(theEnv,theLHS,listOfJoins,RHS); }
            else
              {
               if (duringRetract != NULL)
                 {
                  if (FindEntityInPartialMatch((struct patternEntity *) duringRetract,theLHS) == FALSE)
                    {
                     tempDR = get_struct(theEnv,rdriveinfo);
                     tempDR->link = theLHS;
                     tempDR->jlist = theJoin->nextLevel;
                     tempDR->next = EngineData(theEnv)->DriveRetractionList;
                     EngineData(theEnv)->DriveRetractionList = tempDR;
                    }
                 }
               else while (listOfJoins != NULL)
                 {
                  NetworkAssert(theEnv,theLHS,listOfJoins,LHS);
                  listOfJoins = listOfJoins->rightDriveNode;
                 }
              }
           }
        }
     }
  }

/**************************************************************/
/* FindNextConflictingAlphaMatch: Finds the next conflicting  */
/*   partial match in the alpha memory of a join (or the beta */
/*   memory of a join from the right) that prevents a partial */
/*   match in the beta memory of the join from being          */
/*   satisfied.                                               */
/**************************************************************/
static intBool FindNextConflictingAlphaMatch(
  void *theEnv,
  struct partialMatch *theBind,
  struct partialMatch *possibleConflicts,
  struct joinNode *theJoin)
  {
   int i, result;

   /*=====================================================*/
   /* If we're dealing with a join from the right, then   */
   /* we need to check the entire beta memory of the join */
   /* from the right (a join doesn't have an end of queue */
   /* pointer like a pattern data structure has).         */
   /*=====================================================*/

   if (theJoin->joinFromTheRight)
     { possibleConflicts = ((struct joinNode *) theJoin->rightSideEntryStructure)->beta; }

   /*====================================*/
   /* Check each of the possible partial */
   /* matches which could conflict.      */
   /*====================================*/

   for (;
        possibleConflicts != NULL;
        possibleConflicts = possibleConflicts->next)
     {
      /*=====================================*/
      /* Initially indicate that the partial */
      /* match doesn't conflict.             */
      /*=====================================*/

      result = FALSE;

      /*====================================================*/
      /* A partial match with the counterf flag set is not  */
      /* yet a "real" partial match, so ignore it. When the */
      /* counterf flag is set that means that the partial   */
      /* match is associated with a not CE that has a data  */
      /* entity preventing it from being satsified.         */
      /*====================================================*/

      if (possibleConflicts->counterf)
        { /* Do Nothing */ }

       /*======================================================*/
       /* 6.05 Bug Fix. It is possible that a pattern entity   */
       /* (e.g., instance) in a partial match is 'out of date' */
       /* with respect to the lazy evaluation scheme use by    */
       /* negated patterns. In other words, the object may     */
       /* have changed since it was last pushed through the    */
       /* network, and thus the partial match may be invalid.  */
       /* If so, the partial match must be ignored here.       */
       /*======================================================*/

      else if (PartialMatchDefunct(theEnv,possibleConflicts))
        { /* Do Nothing */ }

      /*==================================================*/
      /* If the join doesn't have a network expression to */
      /* be evaluated, then partial match conflicts. If   */
      /* the partial match is retrieved from a join from  */
      /* the right, the RHS partial match must correspond */
      /* to the partial match in the beta memory of the   */
      /* join being examined (in a join associated with a */
      /* not CE, each partial match in the beta memory of */
      /* the join corresponds uniquely to a partial match */
      /* in either the alpha memory from the RHS or in    */
      /* the beta memory of a join from the right).       */
      /*==================================================*/

      else if (theJoin->networkTest == NULL)
        {
         result = TRUE;
         if (theJoin->joinFromTheRight)
           {
            for (i = 0; i < (int) (theBind->bcount - 1); i++)
              {
               if (possibleConflicts->binds[i].gm.theMatch != theBind->binds[i].gm.theMatch)
                 {
                  result = FALSE;
                  break;
                 }
              }
           }
        }

      /*=================================================*/
      /* Otherwise, if the join has a network expression */
      /* to evaluate, then evaluate it.                  */
      /*=================================================*/

      else
        {
         result = EvaluateJoinExpression(theEnv,theJoin->networkTest,theBind,
                                         possibleConflicts,theJoin);
         if (EvaluationData(theEnv)->EvaluationError)
           {
            result = TRUE;
            EvaluationData(theEnv)->EvaluationError = FALSE;
           }
        }

      /*==============================================*/
      /* If the network expression evaluated to TRUE, */
      /* then partial match being examined conflicts. */
      /* Point the beta memory partial match to the   */
      /* conflicting partial match and return TRUE to */
      /* indicate a conflict was found.               */
      /*==============================================*/

      if (result != FALSE)
        {
         theBind->binds[theBind->bcount - 1].gm.theValue = (void *) possibleConflicts;
         return(TRUE);
        }
     }

   /*========================*/
   /* No conflict was found. */
   /*========================*/

   return(FALSE);
  }

/***********************************************************/
/* PartialMatchDefunct: Determines if any pattern entities */
/*   contained within the partial match have changed since */
/*   this partial match was generated. Assumes counterf is */
/*   FALSE.                                                */
/***********************************************************/
static intBool PartialMatchDefunct(
  void *theEnv,
  struct partialMatch *thePM)
  {
   register unsigned i;
   register struct patternEntity * thePE;

   for (i = 0 ; i < thePM->bcount ; i++)
     {
      thePE = thePM->binds[i].gm.theMatch->matchingItem;
      if (thePE && thePE->theInfo->synchronized &&
          !(*thePE->theInfo->synchronized)(theEnv,thePE))
        return(TRUE);
     }
   return(FALSE);
  }

/*************************************************************/
/* RemovePartialMatches: Searches through a list of partial  */
/*   matches and removes any partial match that contains the */
/*   specified data entity.                                  */
/*************************************************************/
static struct partialMatch *RemovePartialMatches(
  void *theEnv,
  struct alphaMatch *theAlphaNode,
  struct partialMatch *listOfPMs,
  struct partialMatch **deleteHead,
  int position,
  struct partialMatch **returnLast)
  {
   struct partialMatch *head, *lastPM, *nextPM;
   struct partialMatch *lastDelete = NULL;
   
   /*====================================================*/
   /* Initialize pointers used for creating the new list */
   /* of partial matches and the list of partial matches */
   /* to be deleted.                                     */
   /*====================================================*/

   head = listOfPMs;
   lastPM = listOfPMs;
   *deleteHead = NULL;

   /*==========================================*/
   /* Loop through each of the partial matches */
   /* and determine if it needs to be deleted. */
   /*==========================================*/

   while (listOfPMs != NULL)
     {
      if ((listOfPMs->counterf == TRUE) && (position == ((int) (listOfPMs->bcount - 1))))
        {
         lastPM = listOfPMs;
         listOfPMs = listOfPMs->next;
        }

      /*=====================================================*/
      /* Otherwise, if the specified position in the partial */
      /* match contains the specified data entity, then      */
      /* remove the partial match from the list and add it   */
      /* to a deletion list.                                 */
      /*=====================================================*/

      else if (listOfPMs->binds[position].gm.theMatch == theAlphaNode)
        {
         /*===================================================*/
         /* If the partial match has an activation associated */
         /* with it, then return the activation.              */
         /*===================================================*/

         if ((listOfPMs->activationf) ?
             (listOfPMs->binds[listOfPMs->bcount].gm.theValue != NULL) : FALSE)
           { RemoveActivation(theEnv,(struct activation *) listOfPMs->binds[listOfPMs->bcount].gm.theValue,TRUE,TRUE); }

         /*==================================================*/
         /* If the partial match is at the head of the list  */
         /* of matches, then use the following deletion code */
         /* for the head of the list.                        */
         /*==================================================*/

         if (listOfPMs == head)
           {
            /*===================================*/
            /* Remember the new beginning of the */
            /* new list of partial matches.      */
            /*===================================*/

            nextPM = listOfPMs->next;

            /*=============================================*/
            /* Add the partial match to the deletion list. */
            /*=============================================*/

            if (*deleteHead == NULL)
              { *deleteHead = listOfPMs; }
            else
              { lastDelete->next = listOfPMs; }

            listOfPMs->next = NULL;
            lastDelete = listOfPMs;

            /*================================================*/
            /* Update the head and tail pointers for the new  */
            /* list of partial matches as well as the pointer */
            /* to the next partial match to be examined.      */
            /*================================================*/

            listOfPMs = nextPM;
            head = listOfPMs;
            lastPM = head;
           }

         /*======================================*/
         /* Otherwise, use the following code to */
         /* delete the partial match.            */
         /*======================================*/

         else
           {
            /*========================================*/
            /* Detach the partial match being deleted */
            /* from the new list of partial matches.  */
            /*========================================*/

            lastPM->next = listOfPMs->next;

            /*=============================================*/
            /* Add the partial match to the deletion list. */
            /*=============================================*/

            if (*deleteHead == NULL)
              { *deleteHead = listOfPMs; }
            else
              { lastDelete->next = listOfPMs; }

            listOfPMs->next = NULL;
            lastDelete = listOfPMs;

            /*=============================*/
            /* Move on to the next partial */
            /* match to be examined.       */
            /*=============================*/

            listOfPMs = lastPM->next;
           }
        }

      /*==============================================*/
      /* Otherwise, the partial match should be added */
      /* to the new list of partial matches.          */