default.c

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        { return(AddDouble((double) ValueToLong(theConstraints->minValue->value))); }
      else if (theConstraints->maxValue->type == FLOAT)
        { return(theConstraints->maxValue->value); }
      else if (theConstraints->maxValue->type == INTEGER)
        { return(AddDouble((double) ValueToLong(theConstraints->maxValue->value))); }
     }
   
   /*======================================*/
   /* Use the standard default value (such */
   /* as nil if symbols are allowed).      */
   /*======================================*/
        
   return(standardDefault);
  }
  
#if (! RUN_TIME) && (! BLOAD_ONLY)

/**********************************************/
/* ParseDefault: Parses a default value list. */
/**********************************************/
globle struct expr *ParseDefault(readSource,multifield,dynamic,evalStatic,
                                 noneSpecified,deriveSpecified,error)
  char *readSource;
  int multifield;
  int dynamic,evalStatic;
  int *noneSpecified,*deriveSpecified;
  int *error;
  {
   struct expr *defaultList = NULL, *lastDefault = NULL;
   struct expr *newItem, *tmpItem;
   struct token theToken;
   DATA_OBJECT theValue;
   CONSTRAINT_RECORD *rv;
   int specialVarCode;
   
   *noneSpecified = CLIPS_FALSE;
   *deriveSpecified = CLIPS_FALSE;
   
   SavePPBuffer(" ");
   GetToken(readSource,&theToken);
   
   /*===================================================*/
   /* Read the items contained in the default attribute */
   /* until a closing right parenthesis is encountered. */
   /*===================================================*/
   
   while (theToken.type != RPAREN)
     {
      /*========================================*/
      /* Get the next item in the default list. */
      /*========================================*/
       
      newItem = ParseAtomOrExpression(readSource,&theToken);
      if (newItem == NULL)
        {
         ReturnExpression(defaultList);
         *error = CLIPS_TRUE;
         return(NULL);
        }
       
      /*===========================================================*/
      /* Check for invalid variable usage. With the expection of   */
      /* ?NONE for the default attribute, local variables may not  */
      /* be used within the default or default-dynamic attributes. */
      /*===========================================================*/
      
      if ((newItem->type == SF_VARIABLE) || (newItem->type == MF_VARIABLE))
        {
         if (strcmp(ValueToString(newItem->value),"NONE") == 0)
           { specialVarCode = 0; }
         else if (strcmp(ValueToString(newItem->value),"DERIVE") == 0)
           { specialVarCode = 1; }
         else
           { specialVarCode = -1; }
           
         if ((dynamic) ||
             (newItem->type == MF_VARIABLE) ||
             (specialVarCode == -1) ||
             ((specialVarCode != -1) && (defaultList != NULL)))
           {         
            if (dynamic) SyntaxErrorMessage("default-dynamic attribute");
            else SyntaxErrorMessage("default attribute");
            ReturnExpression(newItem);
            ReturnExpression(defaultList);
            *error = CLIPS_TRUE;
            return(NULL);
           }
         
         ReturnExpression(newItem);
         
         /*============================================*/
         /* Check for the closing right parenthesis of */
         /* the default or default dynamic attribute.  */
         /*============================================*/
                  
         GetToken(readSource,&theToken); 
         
         if (theToken.type != RPAREN)
           {
            if (dynamic) SyntaxErrorMessage("default-dynamic attribute");
            else SyntaxErrorMessage("default attribute");
            PPBackup();
            SavePPBuffer(" ");
            SavePPBuffer(theToken.printForm);
            *error = CLIPS_TRUE;
           }
         
         if (specialVarCode == 0)
           *noneSpecified = CLIPS_TRUE;
         else
           *deriveSpecified = CLIPS_TRUE;
         return(NULL);
        }

      /*====================================================*/
      /* Look to see if any variables have been used within */
      /* expressions contained within the default list.     */
      /*====================================================*/
      
      if (ExpressionContainsVariables(newItem,FALSE) == TRUE)
        {
         ReturnExpression(defaultList);
         ReturnExpression(newItem);
         *error = TRUE;
         if (dynamic) SyntaxErrorMessage("default-dynamic attribute");
         else SyntaxErrorMessage("default attribute");
         return(NULL);
        }

      /*============================================*/
      /* Add the default value to the default list. */
      /*============================================*/

      if (lastDefault == NULL)
        { defaultList = newItem; }
      else
        { lastDefault->nextArg = newItem; }
      lastDefault = newItem;

      /*=======================================*/
      /* Begin parsing the next default value. */
      /*=======================================*/

      SavePPBuffer(" ");
      GetToken(readSource,&theToken);
     }

   /*=====================================*/
   /* Fix up pretty print representation. */
   /*=====================================*/

   PPBackup();
   PPBackup();
   SavePPBuffer(")");

   /*=========================================*/
   /* A single field slot's default attribute */
   /* must contain a single value.            */
   /*=========================================*/

   if (multifield == CLIPS_FALSE)
     {
      if (defaultList == NULL)
        { *error = CLIPS_TRUE; }
      else if (defaultList->nextArg != NULL)
        { *error = CLIPS_TRUE; }
      else
        {
         rv = ExpressionToConstraintRecord(defaultList);
         rv->multifieldsAllowed = CLIPS_FALSE;
         if (UnmatchableConstraint(rv)) *error = CLIPS_TRUE;
         RemoveConstraint(rv);
        }
        
      if (*error)
        {
         PrintErrorID("DEFAULT",1,CLIPS_TRUE);
         PrintCLIPS(WERROR,"The default value for a single field slot must be a single field value\n");
         ReturnExpression(defaultList);
         return(NULL);
        }
     }

   /*=======================================================*/
   /* If the dynamic-default attribute is not being parsed, */
   /* evaluate the expressions to make the default value.   */
   /*=======================================================*/
   
   if (dynamic || (! evalStatic) || (defaultList == NULL)) return(defaultList);
   
   tmpItem = defaultList;
   newItem = defaultList;
   
   defaultList = NULL;
      
   while (newItem != NULL)
     {
      SetEvaluationError(CLIPS_FALSE); 
      if (EvaluateExpression(newItem,&theValue)) *error = CLIPS_TRUE;
      
      if ((theValue.type == MULTIFIELD) && 
          (multifield == CLIPS_FALSE) && 
          (*error == CLIPS_FALSE)) 
        {
         PrintErrorID("DEFAULT",1,CLIPS_TRUE);
         PrintCLIPS(WERROR,"The default value for a single field slot must be a single field value\n");
         *error = CLIPS_TRUE;
        }
        
      if (*error)
        {
         ReturnExpression(tmpItem);
         ReturnExpression(defaultList);
         *error = CLIPS_TRUE;
         return(NULL);
        }
        
      lastDefault = ConvertValueToExpression(&theValue); 
      
      defaultList = AppendExpressions(defaultList,lastDefault);
      
      newItem = newItem->nextArg;
     }
   
   ReturnExpression(tmpItem);

   /*==========================*/
   /* Return the default list. */
   /*==========================*/

   return(defaultList);
  }
  
#endif /* (! RUN_TIME) && (! BLOAD_ONLY) */