factbld.c

VC嵌入式CLips专家系统,实现战场环境的目标识别

   FactData(theEnv)->CurrentDeftemplate->patternNetwork = newNode;
   return(newNode);
  }

/*************************************************************/
/* DetachFactPattern: Removes a pattern node and all of its  */
/*   parent nodes from the pattern network. Nodes are only   */
/*   removed if they are no longer shared (i.e. a pattern    */
/*   node that has more than one child node is shared). A    */
/*   pattern from a rule is typically removed by removing    */
/*   the bottom most pattern node used by the pattern and    */
/*   then removing any parent nodes which are not shared by  */
/*   other patterns.                                         */
/*                                                           */
/*   Example:                                                */
/*     Patterns (a b c d) and (a b e f) would be represented */
/*     by the pattern net shown on the left.  If (a b c d)   */
/*     was detached, the resultant pattern net would be the  */
/*     one shown on the right.                               */
/*                                                           */
/*           a                  a                            */
/*           |                  |                            */
/*           b                  b                            */
/*           |                  |                            */
/*           c--e               e                            */
/*           |  |               |                            */
/*           d  f               f                            */
/*                                                           */
/*************************************************************/
static void DetachFactPattern(
  void *theEnv,
  struct patternNodeHeader *thePattern)
  {
   struct factPatternNode *patternPtr;
   struct factPatternNode *upperLevel;

   /*=====================================================*/
   /* Get rid of any matches stored in the alpha memory.  */
   /*=====================================================*/

   patternPtr = (struct factPatternNode *) thePattern;
   ClearPatternMatches(theEnv,patternPtr);

   /*=====================================================*/
   /* If there are no joins entered from this pattern, then */
   /* the pattern node is no longer a stop node. Also if  */
   /* the pattern has a next level pointer, then it can   */
   /* not be removed since other patterns make use of it. */
   /*=====================================================*/

   if (patternPtr->header.entryJoin == NULL) patternPtr->header.stopNode = FALSE;
   if (patternPtr->nextLevel != NULL) return;

   /*==============================================================*/
   /* Loop until all appropriate pattern nodes have been detached. */
   /*==============================================================*/

   upperLevel = patternPtr;
   while (upperLevel != NULL)
     {
      if ((upperLevel->leftNode == NULL) &&
          (upperLevel->rightNode == NULL))
        {
         /*===============================================*/
         /* Pattern node is the only node on this level.  */
         /* Remove it and continue detaching other nodes  */
         /* above this one, because no other patterns are */
         /* dependent upon this node.                     */
         /*===============================================*/

         patternPtr = upperLevel;
         upperLevel = patternPtr->lastLevel;

         if (upperLevel == NULL)
           { FindAndSetDeftemplatePatternNetwork(theEnv,patternPtr,NULL); }
         else
           {
            upperLevel->nextLevel = NULL;
            if (upperLevel->header.stopNode) upperLevel = NULL;
           }

         RemoveHashedExpression(theEnv,patternPtr->networkTest);
         rtn_struct(theEnv,factPatternNode,patternPtr);
        }
      else if (upperLevel->leftNode != NULL)
        {
         /*====================================================*/
         /* Pattern node has another pattern node which must   */
         /* be checked preceding it.  Remove the pattern node, */
         /* but do not detach any nodes above this one.        */
         /*====================================================*/

         patternPtr = upperLevel;
         upperLevel->leftNode->rightNode = upperLevel->rightNode;
         if (upperLevel->rightNode != NULL)
           { upperLevel->rightNode->leftNode = upperLevel->leftNode; }

         RemoveHashedExpression(theEnv,patternPtr->networkTest);
         rtn_struct(theEnv,factPatternNode,patternPtr);
         upperLevel = NULL;
        }
      else
        {
         /*====================================================*/
         /* Pattern node has no pattern node preceding it, but */
         /* does have one succeeding it. Remove the pattern    */
         /* node, but do not detach any nodes above this one.  */
         /*====================================================*/

         patternPtr = upperLevel;
         upperLevel = upperLevel->lastLevel;
         if (upperLevel == NULL)
           { FindAndSetDeftemplatePatternNetwork(theEnv,patternPtr,patternPtr->rightNode); }
         else
           { upperLevel->nextLevel = patternPtr->rightNode; }
         patternPtr->rightNode->leftNode = NULL;

         RemoveHashedExpression(theEnv,patternPtr->networkTest);
         rtn_struct(theEnv,factPatternNode,patternPtr);
         upperLevel = NULL;
        }
     }
  }

#endif

/**************************************************************/
/* DestroyFactPatternNetwork: Deallocates the data structures */
/*   associated with a fact pattern network.                  */
/**************************************************************/
globle void DestroyFactPatternNetwork(
  void *theEnv,
  struct factPatternNode *thePattern)
  {
   struct factPatternNode *patternPtr;
   
   if (thePattern == NULL) return;
   
   while (thePattern != NULL)
     {
      patternPtr = thePattern->rightNode;
      
      DestroyFactPatternNetwork(theEnv,thePattern->nextLevel);
      
      DestroyAlphaBetaMemory(theEnv,thePattern->header.alphaMemory);
      
#if (! BLOAD_ONLY) && (! RUN_TIME)
      rtn_struct(theEnv,factPatternNode,thePattern);
#endif
      
      thePattern = patternPtr;
     }
  }
  
#if (! RUN_TIME) && (! BLOAD_ONLY)
  
/***********************************************************/
/* FindAndSetDeftemplatePatternNetwork: When a deftemplate */
/*   pattern is detached from the fact pattern network, it */
/*   is not possible to directly detach the link from the  */
/*   deftemplate to the pattern network (it is a one way   */
/*   link). Therefore if the top most pointer to a         */
/*   deftemplates pattern network must be changed, it is   */
/*   necessary to search the list of deftemplates to find  */
/*   the appropriate one to modify.                        */
/***********************************************************/
static void FindAndSetDeftemplatePatternNetwork(
  void *theEnv,
  struct factPatternNode *rootNode,
  struct factPatternNode *newRootNode)
  {
   struct deftemplate *theDeftemplate;
   struct defmodule *theModule;

   /*=======================================================*/
   /* Save the current module since we will be changing it. */
   /*=======================================================*/

   SaveCurrentModule(theEnv);

   /*=======================================================*/
   /* Loop through every module looking for the deftemplate */
   /* associated with the specified root node.              */
   /*=======================================================*/

   for (theModule = (struct defmodule *) EnvGetNextDefmodule(theEnv,NULL);
        theModule != NULL;
        theModule = (struct defmodule *) EnvGetNextDefmodule(theEnv,theModule))
     {
      /*======================================================*/
      /* Set the current module to the module being examined. */
      /*======================================================*/

      EnvSetCurrentModule(theEnv,(void *) theModule);

      /*======================================================*/
      /* Loop through every deftemplate in the current module */
      /* searching for the deftemplate associated with the    */
      /* specified root node.                                 */
      /*======================================================*/

      for (theDeftemplate = (struct deftemplate *) EnvGetNextDeftemplate(theEnv,NULL);
           theDeftemplate != NULL;
           theDeftemplate = (struct deftemplate *) EnvGetNextDeftemplate(theEnv,theDeftemplate))
        {
         /*===========================================================*/
         /* When the associated deftemplate is found, change its root */
         /* node from the current value to the new value. Restore the */
         /* current module before leaving this routine.               */
         /*===========================================================*/

         if (theDeftemplate->patternNetwork == rootNode)
           {
            RestoreCurrentModule(theEnv);
            theDeftemplate->patternNetwork = newRootNode;
            return;
           }
        }
     }

   /*========================================================*/
   /* If the deftemplate wasn't found, then we're presumably */
   /* we're in the the middle of a clear and the deftemplate */
   /* has already been deleted so there's no need to update  */
   /* the links to the fact pattern network.                 */
   /*========================================================*/

   RestoreCurrentModule(theEnv);
  }

/***************************************************************/
/* ClearPatternMatches: Clears the fact list of all pointers   */
/*   which point to a specific pattern.  The pointers are used */
/*   to remember which patterns were matched by a fact to      */
/*   make retraction easier.  When a rule is excised, the      */
/*   pointers need to be removed.                              */
/***************************************************************/
static void ClearPatternMatches(
  void *theEnv,
  struct factPatternNode *patternPtr)
  {
   struct fact *theFact;
   struct patternMatch *lastMatch, *theMatch;

   /*===========================================*/
   /* Loop through every fact in the fact list. */
   /*===========================================*/

   for (theFact = (struct fact *) EnvGetNextFact(theEnv,NULL);
        theFact != NULL;
        theFact = (struct fact *) EnvGetNextFact(theEnv,theFact))
     {
      /*========================================*/
      /* Loop through every match for the fact. */
      /*========================================*/

      lastMatch = NULL;
      theMatch = (struct patternMatch *) theFact->list;

      while (theMatch != NULL)
        {
         /*================================================*/
         /* If the match is for the pattern being deleted, */
         /* then remove the match.                         */
         /*================================================*/

         if (theMatch->matchingPattern == (struct patternNodeHeader *) patternPtr)
           {
            if (lastMatch == NULL)
              {
               /*=====================================*/
               /* Remove the first match of the fact. */
               /*=====================================*/

               theFact->list = (void *) theMatch->next;
               rtn_struct(theEnv,patternMatch,theMatch);
               theMatch = (struct patternMatch *) theFact->list;
              }
            else
             {
               /*===================================*/
               /* Remove a match for the fact which */
               /* follows the first match.          */
               /*===================================*/

              lastMatch->next = theMatch->next;
              rtn_struct(theEnv,patternMatch,theMatch);
              theMatch = lastMatch->next;
             }
           }

         /*====================================================*/
         /* If the match is not for the pattern being deleted, */
         /* then move on to the next match for the fact.       */
         /*====================================================*/

         else
          {
           lastMatch = theMatch;
           theMatch = theMatch->next;
          }
       }
    }
  }
  
#endif /* (! RUN_TIME) && (! BLOAD_ONLY) */

#endif /* DEFTEMPLATE_CONSTRUCT && DEFRULE_CONSTRUCT */