factrhs.c

clips源代码

        { theDeftemplate = CreateImpliedDeftemplate(theEnv,(SYMBOL_HN *) templateName,TRUE); }
     }
#else
    {
     NoSuchTemplateError(theEnv,ValueToString(templateName));
     *error = TRUE;
     return(NULL);
    }
#endif

   /*=========================================*/
   /* If an explicit deftemplate exists, then */
   /* parse the fact as a deftemplate fact.   */
   /*=========================================*/

   if ((theDeftemplate != NULL) && (theDeftemplate->implied == FALSE))
     {
      firstOne = GenConstant(theEnv,DEFTEMPLATE_PTR,theDeftemplate);
      firstOne->nextArg = ParseAssertTemplate(theEnv,readSource,tempToken,
                                              error,endType,
                                              constantsOnly,theDeftemplate);
      if (*error)
        {
         ReturnExpression(theEnv,firstOne);
         firstOne = NULL;
        }

      return(firstOne);
     }

   /*========================================*/
   /* Parse the fact as an ordered RHS fact. */
   /*========================================*/

   firstOne = GenConstant(theEnv,DEFTEMPLATE_PTR,theDeftemplate);

#if (! RUN_TIME) && (! BLOAD_ONLY)
   SavePPBuffer(theEnv," ");
#endif

   while ((nextOne = GetAssertArgument(theEnv,readSource,tempToken,
                                        error,endType,constantsOnly,&printError)) != NULL)
     {
      if (argHead == NULL) argHead = nextOne;
      else lastOne->nextArg = nextOne;
      lastOne = nextOne;
#if (! RUN_TIME) && (! BLOAD_ONLY)
      SavePPBuffer(theEnv," ");
#endif
     }

   /*===========================================================*/
   /* If an error occurred, set the error flag and return NULL. */
   /*===========================================================*/

   if (*error)
     {
      if (printError) SyntaxErrorMessage(theEnv,"RHS patterns");
      ReturnExpression(theEnv,firstOne);
      ReturnExpression(theEnv,argHead);
      return(NULL);
     }

   /*=====================================*/
   /* Fix the pretty print representation */
   /* of the RHS ordered fact.            */
   /*=====================================*/

#if (! RUN_TIME) && (! BLOAD_ONLY)
   PPBackup(theEnv);
   PPBackup(theEnv);
   SavePPBuffer(theEnv,tempToken->printForm);
#endif

   /*==========================================================*/
   /* Ordered fact assertions are processed by stuffing all of */
   /* the fact's proposition (except the relation name) into a */
   /* single multifield slot.                                  */
   /*==========================================================*/

   firstOne->nextArg = GenConstant(theEnv,FACT_STORE_MULTIFIELD,AddBitMap(theEnv,(void *) "\0",1));
   firstOne->nextArg->argList = argHead;

   /*==============================*/
   /* Return the RHS ordered fact. */
   /*==============================*/

   return(firstOne);
  }

/********************************************************************/
/* GetAssertArgument: Parses a single RHS slot value and returns an */
/*   expression representing the value. When parsing a deftemplate  */
/*   slot, the slot name has already been parsed when this function */
/*   is called. NULL is returned if a slot or fact delimiter is     */
/*   encountered. In the event of a parse error, the error flag     */
/*   passed as an argument is set.                                  */
/********************************************************************/
globle struct expr *GetAssertArgument(
  void *theEnv,
  char *logicalName,
  struct token *theToken,
  int *error,
  int endType,
  int constantsOnly,
  int *printError)
  {
#if ! RUN_TIME
   struct expr *nextField;
#else
   struct expr *nextField = NULL;
#endif

   /*=================================================*/
   /* Read in the first token of the slot's value. If */
   /* the end delimiter is encountered, then return.  */
   /*=================================================*/

   *printError = TRUE;
   GetToken(theEnv,logicalName,theToken);
   if (theToken->type == endType) return(NULL);

   /*=============================================================*/
   /* If an equal sign of left parenthesis was parsed, then parse */
   /* a function which is to be evaluated to determine the slot's */
   /* value. The equal sign corresponds to the return value       */
   /* constraint which can be used in LHS fact patterns. The      */
   /* equal sign is no longer necessary on either the LHS or RHS  */
   /* of a rule to indicate that a function is being evaluated to */
   /* determine its value either for assignment or pattern        */
   /* matching.                                                   */
   /*=============================================================*/

   if ((theToken->type == SYMBOL) ?
       (strcmp(ValueToString(theToken->value),"=") == 0) :
       (theToken->type == LPAREN))
     {
      if (constantsOnly)
        {
         *error = TRUE;
         return(NULL);
        }

#if ! RUN_TIME
      if (theToken->type == LPAREN) nextField = Function1Parse(theEnv,logicalName);
      else nextField = Function0Parse(theEnv,logicalName);
      if (nextField == NULL)
#endif
        {
         *printError = FALSE;
         *error = TRUE;
        }
#if ! RUN_TIME
      else
        {
         theToken->type= RPAREN;
         theToken->value = (void *) EnvAddSymbol(theEnv,")");
         theToken->printForm = ")";
        }
#endif

      return(nextField);
     }

   /*==================================================*/
   /* Constants are always allowed as RHS slot values. */
   /*==================================================*/

   if ((theToken->type == SYMBOL) || (theToken->type == STRING) ||
#if OBJECT_SYSTEM
           (theToken->type == INSTANCE_NAME) ||
#endif
           (theToken->type == FLOAT) || (theToken->type == INTEGER))
     { return(GenConstant(theEnv,theToken->type,theToken->value)); }

   /*========================================*/
   /* Variables are also allowed as RHS slot */
   /* values under some circumstances.       */
   /*========================================*/

   if ((theToken->type == SF_VARIABLE) ||
#if DEFGLOBAL_CONSTRUCT
            (theToken->type == GBL_VARIABLE) ||
            (theToken->type == MF_GBL_VARIABLE) ||
#endif
            (theToken->type == MF_VARIABLE))
     {
      if (constantsOnly)
        {
         *error = TRUE;
         return(NULL);
        }

      return(GenConstant(theEnv,theToken->type,theToken->value));
     }

   /*==========================================================*/
   /* If none of the other cases have been satisfied, then the */
   /* token parsed is not appropriate for a RHS slot value.    */
   /*==========================================================*/

   *error = TRUE;
   return(NULL);
  }

/****************************************************/
/* StringToFact: Converts the string representation */
/*   of a fact to a fact data structure.            */
/****************************************************/
globle struct fact *StringToFact(
  void *theEnv,
  char *str)
  {
   struct token theToken;
   struct fact *factPtr;
   unsigned numberOfFields = 0, whichField;
   struct expr *assertArgs, *tempPtr;
   int error = FALSE;
   DATA_OBJECT theResult;

   /*=========================================*/
   /* Open a string router and parse the fact */
   /* using the router as an input source.    */
   /*=========================================*/
   
   SetEvaluationError(theEnv,FALSE);

   OpenStringSource(theEnv,"assert_str",str,0);

   assertArgs = GetRHSPattern(theEnv,"assert_str",&theToken,
                              &error,FALSE,TRUE,
                              TRUE,RPAREN);

   CloseStringSource(theEnv,"assert_str");

   /*===========================================*/
   /* Check for errors or the use of variables. */
   /*===========================================*/
   
   if ((assertArgs == NULL) && (! error))
     {
      SyntaxErrorMessage(theEnv,"RHS patterns");
      ReturnExpression(theEnv,assertArgs);
      return(NULL);
     }

   if (error)
     {
      ReturnExpression(theEnv,assertArgs);
      return(NULL);
     }

   if (ExpressionContainsVariables(assertArgs,FALSE))
     {
      LocalVariableErrorMessage(theEnv,"the assert-string function");
      SetEvaluationError(theEnv,TRUE);
      ReturnExpression(theEnv,assertArgs);
      return(NULL);
     }

   /*=======================================================*/
   /* Count the number of fields needed for the fact and    */
   /* create a fact data structure of the appropriate size. */
   /*=======================================================*/

   for (tempPtr = assertArgs->nextArg; tempPtr != NULL; tempPtr = tempPtr->nextArg)
     { numberOfFields++; }

   factPtr = (struct fact *) CreateFactBySize(theEnv,numberOfFields);
   factPtr->whichDeftemplate = (struct deftemplate *) assertArgs->value;

   /*=============================================*/
   /* Copy the fields to the fact data structure. */
   /*=============================================*/

   ExpressionInstall(theEnv,assertArgs); /* DR0836 */
   whichField = 0;
   for (tempPtr = assertArgs->nextArg; tempPtr != NULL; tempPtr = tempPtr->nextArg)
     {
      EvaluateExpression(theEnv,tempPtr,&theResult);
      factPtr->theProposition.theFields[whichField].type = theResult.type;
      factPtr->theProposition.theFields[whichField].value = theResult.value;
      whichField++;
     }
   ExpressionDeinstall(theEnv,assertArgs); /* DR0836 */
   ReturnExpression(theEnv,assertArgs);

   /*==================*/
   /* Return the fact. */
   /*==================*/

   return(factPtr);
  }

#if RUN_TIME || BLOAD_ONLY || BLOAD || BLOAD_AND_BSAVE

/*********************************************************/
/* NoSuchTemplateError: Prints out an error message      */
/* in a BLOAD_ONLY, RUN_TIME or bload active environment */
/* when an implied deftemplate cannot be created for     */
/* an assert                                             */
/*********************************************************/
static void NoSuchTemplateError(
  void *theEnv,
  char *templateName)
  {
   PrintErrorID(theEnv,"FACTRHS",1,FALSE);
   EnvPrintRouter(theEnv,WERROR,"Template ");
   EnvPrintRouter(theEnv,WERROR,templateName);
   EnvPrintRouter(theEnv,WERROR," does not exist for assert.\n");
  }

#endif /* RUN_TIME || BLOAD_ONLY || BLOAD || BLOAD_AND_BSAVE */

#endif /* DEFTEMPLATE_CONSTRUCT */