generate.c

NASA 开发使用的一个专家系统

   /*******************************************************/
   /*      "C" Language Integrated Production System      */
   /*                                                     */
   /*             CLIPS Version 6.05  04/09/97            */
   /*                                                     */
   /*                   GENERATE MODULE                   */
   /*******************************************************/

/*************************************************************/
/* Purpose: Provides routines for converting field           */
/*   constraints to expressions which can be used            */
/*   in the pattern and join networks.                       */
/*                                                           */
/* Principal Programmer(s):                                  */
/*      Gary D. Riley                                        */
/*                                                           */
/* Contributing Programmer(s):                               */
/*                                                           */
/* Revision History:                                         */
/*                                                           */
/*************************************************************/

#define _GENERATE_SOURCE_

#include <stdio.h>
#define _CLIPS_STDIO_

#include "setup.h"

#if (! RUN_TIME) && (! BLOAD_ONLY) && DEFRULE_CONSTRUCT

#include "constant.h"
#include "clipsmem.h"
#include "symbol.h"
#include "exprnpsr.h"
#include "argacces.h"
#include "extnfunc.h"
#include "router.h"
#include "ruledef.h"
#include "pattern.h"
#include "generate.h"

#if DEFGLOBAL_CONSTRUCT
#include "globlpsr.h"
#endif

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

#if ANSI_COMPILER  
   static VOID                    ExtractAnds(struct lhsParseNode *,int,
                                              struct expr **,struct expr **);
   static VOID                    ExtractFieldTest(struct lhsParseNode *,int,
                                                   struct expr **,struct expr **);
   static struct expr            *GetfieldReplace(struct lhsParseNode *);
   static struct expr            *GenPNConstant(struct lhsParseNode *);
   static struct expr            *GenJNConstant(struct lhsParseNode *);
   static struct expr            *GenJNColon(struct lhsParseNode *);
   static struct expr            *GenPNColon(struct lhsParseNode *);
   static struct expr            *GenJNEq(struct lhsParseNode *);
   static struct expr            *GenPNEq(struct lhsParseNode *);
   static struct expr            *GenJNVariableComparison(struct lhsParseNode *,
                                                          struct lhsParseNode *);
   static struct expr            *GenPNVariableComparison(struct lhsParseNode *,
                                                          struct lhsParseNode *);
   static int                     AllVariablesInPattern(struct lhsParseNode *,
                                                        int);
   static int                     AllVariablesInExpression(struct lhsParseNode *,
                                                           int);
#else
   static VOID                    ExtractAnds();
   static VOID                    ExtractFieldTest();
   static struct expr            *GetfieldReplace();
   static struct expr            *GenPNConstant();
   static struct expr            *GenJNConstant();
   static struct expr            *GenJNColon();
   static struct expr            *GenPNColon();
   static struct expr            *GenJNEq();
   static struct expr            *GenPNEq();
   static struct expr            *GenJNVariableComparison();
   static struct expr            *GenPNVariableComparison();
   static int                     AllVariablesInPattern();
   static int                     AllVariablesInExpression();
#endif

/*******************************************************/
/* FieldConversion: Generates join and pattern network */
/*   expressions for a field constraint.               */
/*******************************************************/
globle VOID FieldConversion(theField,thePattern)
  struct lhsParseNode *theField;
  struct lhsParseNode *thePattern;
  {
   int testInPatternNetwork = CLIPS_TRUE;
   struct lhsParseNode *patternPtr;
   struct expr *headOfPNExpression, *headOfJNExpression;
   struct expr *lastPNExpression, *lastJNExpression;
   struct expr *tempExpression;
   struct expr *patternNetTest = NULL;
   struct expr *joinNetTest = NULL;

   /*==================================================*/
   /* Consider a NULL pointer to be an internal error. */
   /*==================================================*/
   
   if (theField == NULL)
     {
      CLIPSSystemError("ANALYSIS",3);
      ExitCLIPS(4);
     }
        
   /*========================================================*/
   /* Determine if constant testing must be performed in the */
   /* join network. Only possible when a field contains an   */
   /* or ('|') and references are made to variables outside  */
   /* the pattern.                                           */
   /*========================================================*/

   if (theField->bottom != NULL)
     {
      if (theField->bottom->bottom != NULL)
        { testInPatternNetwork = AllVariablesInPattern(theField->bottom,theField->pattern); }
     }

   /*=============================================================*/
   /* Extract pattern and join network expressions. Loop through  */
   /* the or'ed constraints of the field, extracting pattern and  */
   /* join network expressions and adding them to a running list. */
   /*=============================================================*/

   headOfPNExpression = lastPNExpression = NULL;
   headOfJNExpression = lastJNExpression = NULL;

   for (patternPtr = theField->bottom;
        patternPtr != NULL;
        patternPtr = patternPtr->bottom)
     {
      /*=============================================*/
      /* Extract pattern and join network tests from */
      /* the or'ed constraint being examined.        */
      /*=============================================*/
      
      ExtractAnds(patternPtr,testInPatternNetwork,&patternNetTest,&joinNetTest);

      /*=====================================================*/
      /* Add the new pattern network expressions to the list */
      /* of pattern network expressions being constructed.   */
      /*=====================================================*/
      
      if (patternNetTest != NULL)
        {
         if (lastPNExpression == NULL)
           { headOfPNExpression = patternNetTest; }
         else
           { lastPNExpression->nextArg = patternNetTest; }
         lastPNExpression = patternNetTest;
        }

      /*==================================================*/
      /* Add the new join network expressions to the list */
      /* of join network expressions being constructed.   */
      /*==================================================*/
      
      if (joinNetTest != NULL)
        {
         if (lastJNExpression == NULL)
           { headOfJNExpression = joinNetTest; }
         else
           { lastJNExpression->nextArg = joinNetTest; }
         lastJNExpression = joinNetTest;
        }
     }

   /*==========================================================*/
   /* If there was more than one expression generated from the */
   /* or'ed field constraints for the pattern network, then    */
   /* enclose the expressions within an "or" function call.    */
   /*==========================================================*/
   
   if ((headOfPNExpression != NULL) ? (headOfPNExpression->nextArg != NULL) : CLIPS_FALSE)
     {
      tempExpression = GenConstant(FCALL,PTR_OR);
      tempExpression->argList = headOfPNExpression;
      headOfPNExpression = tempExpression;
     }

   /*==========================================================*/
   /* If there was more than one expression generated from the */
   /* or'ed field constraints for the join network, then       */
   /* enclose the expressions within an "or" function call.    */
   /*==========================================================*/

   if ((headOfJNExpression != NULL) ? (headOfJNExpression->nextArg != NULL) : CLIPS_FALSE)
     {
      tempExpression = GenConstant(FCALL,PTR_OR);
      tempExpression->argList = headOfJNExpression;
      headOfJNExpression = tempExpression;
     }

   /*===============================================================*/
   /* If the field constraint binds a variable that was previously  */
   /* bound somewhere in the LHS of the rule, then generate an      */
   /* expression to compare this binding occurrence of the variable */ 
   /* to the previous binding occurrence.                           */
   /*===============================================================*/

   if (((theField->type == MF_VARIABLE) || (theField->type == SF_VARIABLE)) &&
       (theField->referringNode != NULL))
     {
      /*================================================================*/
      /* If the previous variable reference is within the same pattern, */
      /* then the variable comparison can occur in the pattern network. */
      /*================================================================*/
      
      if (theField->referringNode->pattern == theField->pattern)
        {
         tempExpression = GenPNVariableComparison(theField,theField->referringNode);
         headOfPNExpression = CombineExpressions(tempExpression,headOfPNExpression);
        }
      
      /*====================================*/
      /* Otherwise, the variable comparison */
      /* must occur in the join network.    */
      /*====================================*/
      
      else if (theField->referringNode->pattern > 0)
        {
         tempExpression = GenJNVariableComparison(theField,theField->referringNode);
         headOfJNExpression = CombineExpressions(tempExpression,headOfJNExpression);
        }
     }
   
   /*======================================================*/
   /* Attach the pattern network expressions to the field. */
   /*======================================================*/
   
   theField->networkTest = headOfPNExpression;
   
   /*=====================================================*/
   /* Attach the join network expressions to the pattern. */
   /*=====================================================*/
   
   thePattern->networkTest = CombineExpressions(thePattern->networkTest,headOfJNExpression);
  }

/****************************************************************************/
/* ExtractAnds: Loops through a single set of subfields bound together by   */
/*   an & connective constraint in a field and generates expressions needed */
/*   for testing conditions in the pattern and join network.                */
/****************************************************************************/
static VOID ExtractAnds(andField,testInPatternNetwork,patternNetTest,joinNetTest)
  struct lhsParseNode *andField;
  int testInPatternNetwork;
  struct expr **patternNetTest;
  struct expr **joinNetTest;
  {
   struct expr *newPNTest, *newJNTest;

   /*=================================================*/
   /* Before starting, the subfield has no pattern or */
   /* join network expressions associated with it.    */
   /*=================================================*/
   
   *patternNetTest = NULL;
   *joinNetTest = NULL;
   
   /*=========================================*/
   /* Loop through each of the subfields tied */
   /* together by the & constraint.           */
   /*=========================================*/
   
   for (;
        andField != NULL;
        andField = andField->right)
     {
      /*======================================*/
      /* Extract the pattern and join network */
      /* expressions from the subfield.       */
      /*======================================*/
      
      ExtractFieldTest(andField,testInPatternNetwork,&newPNTest,&newJNTest);
         
      /*=================================================*/
      /* Add the new expressions to the list of pattern  */
      /* and join network expressions being constructed. */
      /*=================================================*/
            
      *patternNetTest = CombineExpressions(*patternNetTest,newPNTest);