retract.c

VC嵌入式CLips专家系统,实现战场环境的目标识别

   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*             CLIPS Version 6.24  05/17/06            */
   /*                                                     */
   /*                   RETRACT MODULE                    */
   /*******************************************************/

/*************************************************************/
/* Purpose:  Handles join network activity associated with   */
/*   with the removal of a data entity such as a fact or     */
/*   instance.                                               */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Gary D. Riley                                        */
/*                                                           */
/* Contributing Programmer(s):                               */
/*                                                           */
/* Revision History:                                         */
/*                                                           */
/*      6.24: Removed LOGICAL_DEPENDENCIES compilation flag. */
/*                                                           */
/*            Renamed BOOLEAN macro type to intBool.         */
/*                                                           */
/*            Rule with exists CE has incorrect activation.  */
/*            DR0867                                         */
/*                                                           */
/*************************************************************/

#define _RETRACT_SOURCE_

#include <stdio.h>
#define _STDIO_INCLUDED_
#include <stdlib.h>

#include "setup.h"

#if DEFRULE_CONSTRUCT

#include "agenda.h"
#include "argacces.h"
#include "constant.h"
#include "drive.h"
#include "engine.h"
#include "envrnmnt.h"
#include "lgcldpnd.h"
#include "match.h"
#include "memalloc.h"
#include "network.h"
#include "reteutil.h"
#include "router.h"
#include "symbol.h"

#include "retract.h"

/***************************************/
/* LOCAL INTERNAL FUNCTION DEFINITIONS */
/***************************************/

   static struct partialMatch    *RemovePartialMatches(void *,struct alphaMatch *,
                                                      struct partialMatch *,
                                                      struct partialMatch **,int,
                                                      struct partialMatch **);
   static void                    DeletePartialMatches(void *,struct partialMatch *,int);
   static void                    ReturnMarkers(void *,struct multifieldMarker *);
   static void                    DriveRetractions(void *);
   static intBool                 FindNextConflictingAlphaMatch(void *,struct partialMatch *,
                                                                struct partialMatch *,
                                                                struct joinNode *);
   static intBool                 PartialMatchDefunct(void *,struct partialMatch *);

/************************************************************/
/* NetworkRetract:  Retracts a data entity (such as a fact  */
/*   or instance) from the pattern and join networks given  */
/*   a pointer to the list of patterns which the data       */
/*   entity matched. The data entity is first removed from  */
/*   the join network through patterns not directly         */
/*   enclosed within a not CE and then through patterns     */
/*   enclosed by a not CE. Any new partial matches created  */
/*   by the removal are then filtered through the join      */
/*   network. This ordering prevents partial matches from   */
/*   being generated that contain the data entity which was */
/*   removed.                                               */
/************************************************************/
globle void NetworkRetract(
  void *theEnv,
  struct patternMatch *listOfMatchedPatterns)
  {
   struct patternMatch *tempMatch;
   struct partialMatch *deletedMatches, *theLast;
   struct joinNode *joinPtr;

   /*===============================*/
   /* Remember the beginning of the */
   /* list of matched patterns.     */
   /*===============================*/

   tempMatch = listOfMatchedPatterns;

   /*============================================*/
   /* Remove the data entity from all joins that */
   /* aren't directly enclosed by a not CE.      */
   /*============================================*/

   for (;
        listOfMatchedPatterns != NULL;
        listOfMatchedPatterns = listOfMatchedPatterns->next)
     {
      /*====================================*/
      /* Loop through the list of all joins */
      /* attached to this pattern.          */
      /*====================================*/

      for (joinPtr = listOfMatchedPatterns->matchingPattern->entryJoin;
           joinPtr != NULL;
           joinPtr = joinPtr->rightMatchNode)
        {
         if (joinPtr->patternIsNegated == FALSE)
           { PosEntryRetract(theEnv,joinPtr,
                             listOfMatchedPatterns->theMatch->binds[0].gm.theMatch,
                             listOfMatchedPatterns->theMatch,
                             (int) joinPtr->depth - 1,listOfMatchedPatterns->theMatch->binds[0].gm.theMatch->matchingItem); }
        }
     }

   /*============================================*/
   /* Remove the data entity from all joins that */
   /* are directly enclosed by a not CE.         */
   /*============================================*/

   listOfMatchedPatterns = tempMatch;
   while (listOfMatchedPatterns != NULL)
     {
      /*====================================*/
      /* Loop through the list of all joins */
      /* attached to this pattern.          */
      /*====================================*/

      for (joinPtr = listOfMatchedPatterns->matchingPattern->entryJoin;
           joinPtr != NULL;
           joinPtr = joinPtr->rightMatchNode)
        {
         if (joinPtr->patternIsNegated == TRUE)
           {
            if (joinPtr->firstJoin == TRUE)
              {
               SystemError(theEnv,"RETRACT",3);
               EnvExitRouter(theEnv,EXIT_FAILURE);
              }
            else
              { 
               NegEntryRetract(theEnv,joinPtr,listOfMatchedPatterns->theMatch,listOfMatchedPatterns->theMatch->binds[0].gm.theMatch->matchingItem); 
              }
           }
        }

      /*===================================================*/
      /* Remove from the alpha memory of the pattern node. */
      /*===================================================*/

      theLast = NULL;
      listOfMatchedPatterns->matchingPattern->alphaMemory =
      RemovePartialMatches(theEnv,listOfMatchedPatterns->theMatch->binds[0].gm.theMatch,
                                listOfMatchedPatterns->matchingPattern->alphaMemory,
                                &deletedMatches,0,&theLast);
      listOfMatchedPatterns->matchingPattern->endOfQueue = theLast;

      DeletePartialMatches(theEnv,deletedMatches,0);

      tempMatch = listOfMatchedPatterns->next;
      rtn_struct(theEnv,patternMatch,listOfMatchedPatterns);
      listOfMatchedPatterns = tempMatch;
     }

   /*=========================================*/
   /* Filter new partial matches generated by */
   /* retraction through the join network.    */
   /*=========================================*/

   DriveRetractions(theEnv);
  }

/***************************************************************/
/* PosEntryRetract:  Handles retract for a join of a rule with */
/*    a positive pattern when the retraction is starting from  */
/*    the RHS of that join (empty or positive LHS entry,       */
/*    positive RHS entry), or the LHS of that join (positive   */
/*    LHS entry, negative or positive RHS entry).              */
/***************************************************************/
globle void PosEntryRetract(
  void *theEnv,
  struct joinNode *join,
  struct alphaMatch *theAlphaNode,
  struct partialMatch *theMatch,
  int position,
  void *duringRetract)
  {
   struct partialMatch *deletedMatches;
   struct joinNode *joinPtr;
   struct partialMatch *theLast;

   while (join != NULL)
     {
      /*=========================================*/
      /* Remove the bindings from this join that */
      /* contain the fact to be retracted.       */
      /*=========================================*/

      if (join->beta == NULL) return; /* optimize */

      join->beta = RemovePartialMatches(theEnv,theAlphaNode,join->beta,&deletedMatches,
                                        position,&theLast);

      /*===================================================*/
      /* If no facts were deleted at this join, then there */
      /* is no need to check joins at a lower level.       */
      /*===================================================*/

      if (deletedMatches == NULL) return;

      /*==================================================*/
      /* If there is more than one join below this join,  */
      /* then recursively remove fact bindings from all   */
      /* but one of the lower joins.  Remove the bindings */
      /* from the other join through this loop.           */
      /*==================================================*/

      joinPtr = join->nextLevel;
      if (joinPtr == NULL)
        {
         DeletePartialMatches(theEnv,deletedMatches,1);
         return;
        }

      if (((struct joinNode *) (joinPtr->rightSideEntryStructure)) == join)
        {
         theMatch = deletedMatches;
         while (theMatch != NULL)
           {
            NegEntryRetract(theEnv,joinPtr,theMatch,duringRetract);
            theMatch = theMatch->next;
           }

         DeletePartialMatches(theEnv,deletedMatches,1);
         return;
        }

      DeletePartialMatches(theEnv,deletedMatches,1);
      while (joinPtr->rightDriveNode != NULL)
        {
         PosEntryRetract(theEnv,joinPtr,theAlphaNode,theMatch,position,duringRetract);
         joinPtr = joinPtr->rightDriveNode;
        }

      join = joinPtr;
     }
  }

/*****************************************************************/
/* NegEntryRetract:  Handles retract for a join of a rule with a */
/*    not CE when the retraction is process from the RHS of that */
/*    join.                                                      */
/*****************************************************************/
void NegEntryRetract(
  void *theEnv,
  struct joinNode *theJoin,
  struct partialMatch *theMatch,
  void *duringRetract)
  {
   struct partialMatch *theLHS;
   int result;
   struct rdriveinfo *tempDR;
   struct alphaMatch *tempAlpha;
   struct joinNode *listOfJoins;

   /*===============================================*/
   /* Loop through all LHS partial matches checking */
   /* for sets that satisfied the join expression.  */
   /*===============================================*/

   for (theLHS = theJoin->beta; theLHS != NULL; theLHS = theLHS->next)
     {
      /*===========================================================*/
      /* Don't bother checking partial matches that are satisfied. */
      /* We're looking for joins from which the removal of a       */
      /* partial match would satisfy the join.                     */
      /*===========================================================*/

      if (theLHS->counterf == FALSE) continue;

      /*==================================================*/
      /* If the partial match being removed isn't the one */
      /* preventing the LHS partial match from being      */
      /* satisifed, then don't bother processing it.      */
      /*==================================================*/

      if (theLHS->binds[theLHS->bcount - 1].gm.theValue != (void *) theMatch) continue;

      /*======================================================*/
      /* Try to find another RHS partial match which prevents */
      /* the LHS partial match from being satisifed.          */
      /*======================================================*/

      theLHS->binds[theLHS->bcount - 1].gm.theValue = NULL;
      result = FindNextConflictingAlphaMatch(theEnv,theLHS,theMatch->next,theJoin);

      /*=========================================================*/
      /* If the LHS partial match now has no RHS partial matches */
      /* that conflict with it, then it satisfies the conditions */
      /* of the RHS not CE. Create a partial match and send it   */
      /* to the joins below.                                     */
      /*=========================================================*/

      if (result == FALSE)
        {
         /*===============================*/
         /* Create the new partial match. */
         /*===============================*/

         theLHS->counterf = FALSE;
         tempAlpha = get_struct(theEnv,alphaMatch);
         tempAlpha->next = NULL;
         tempAlpha->matchingItem = NULL;
         tempAlpha->markers = NULL;
         theLHS->binds[theLHS->bcount - 1].gm.theMatch = tempAlpha;

         /*==============================================*/
         /* If partial matches from this join correspond */
         /* to a rule activation, then add an activation */
         /* to the agenda.                               */