scanner.c

NASA 开发使用的一个专家系统

   while ( (inchar != '<') && (inchar != '"') &&
           (inchar != '(') && (inchar != ')') &&
           (inchar != '&') && (inchar != '|') && (inchar != '~') &&
           (inchar != ' ') && (inchar != ';') &&
           isprint(inchar) )
     {
      GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);


      count++;
      inchar = GetcCLIPS(logicalName);
     }

   /*===================================================*/
   /* Return the last character scanned (the delimiter) */
   /* to the input stream so it will be scanned as part */
   /* of the next token.                                */
   /*===================================================*/

   UngetcCLIPS(inchar,logicalName);

   /*====================================================*/
   /* Add the symbol to the symbol table and return the  */
   /* symbol table address of the symbol. Symbols of the */
   /* form [<symbol>] are instance names, so the type    */
   /* returned is INSTANCE_NAME rather than SYMBOL.      */
   /*====================================================*/

#if OBJECT_SYSTEM
   if (count > 2)
     {
      if ((GlobalString[0] == '[') ? (GlobalString[count-1] == ']') : CLIPS_FALSE)
        {
         *type = INSTANCE_NAME;
         inchar = ']';
        }
      else
        {
         *type = SYMBOL;
         return(AddSymbol(GlobalString));
        }
      GlobalString[count-1] = EOS;
      symbol = AddSymbol(GlobalString+1);
      GlobalString[count-1] = (char) inchar;
      return(symbol);
     }
   else
     {
      *type = SYMBOL;
      return(AddSymbol(GlobalString));
     }
#else
   *type = SYMBOL;
   return(AddSymbol(GlobalString));
#endif
  }

/*************************************/
/* ScanString: Scans a string token. */
/*************************************/
static VOID *ScanString(logicalName)
  char *logicalName;
  {
   int inchar;
   int pos = 0, max = 0;
   char *theString = NULL;
   VOID *thePtr;
   
   /*============================================*/
   /* Scan characters and add them to the string */
   /* until the " delimiter is found.            */
   /*============================================*/

   inchar = GetcCLIPS(logicalName);
   while ((inchar != '"') && (inchar != EOF))
     {
      if (inchar == '\\')
        { inchar = GetcCLIPS(logicalName); }

      theString = ExpandStringWithChar(inchar,theString,&pos,&max,max+80);
      inchar = GetcCLIPS(logicalName);
     }

   if ((inchar == EOF) && (IgnoreCompletionErrors == CLIPS_FALSE))
     { PrintCLIPS(WERROR,"\nEncountered End-Of-File while scanning a string\n"); }

   /*===============================================*/
   /* Add the string to the symbol table and return */
   /* the symbol table address of the string.       */
   /*===============================================*/
   
   if (theString == NULL)
     { thePtr = AddSymbol(""); }
   else
     {
      thePtr = AddSymbol(theString);
      rm(theString,max);
     }

   return(thePtr);
  }

/**************************************/
/* ScanNumber: Scans a numeric token. */
/**************************************/
static VOID ScanNumber(logicalName,theToken)
  char *logicalName;
  struct token *theToken;
  {
   int count = 0;
   int inchar, phase;
   int digitFound = CLIPS_FALSE;
   int processFloat = CLIPS_FALSE;
   double fvalue;
   long lvalue;
   int type;

   /* Phases:              */
   /*  -1 = sign           */
   /*   0 = integral       */
   /*   1 = decimal        */
   /*   2 = exponent-begin */
   /*   3 = exponent-value */
   /*   5 = done           */
   /*   9 = error          */

   inchar = GetcCLIPS(logicalName);
   phase = -1;

   while ((phase != 5) && (phase != 9))
     {
      if (phase == -1)
        {
         if (isdigit(inchar))
           {
            phase = 0;
            digitFound = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
         else if ((inchar == '+') || (inchar == '-'))
           {
            phase = 0;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
         else if (inchar == '.')
           {
            processFloat = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 1;
           }
         else if ((inchar == 'E') || (inchar == 'e'))
           {
            processFloat = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 2;
           }
         else if ( (inchar == '<') || (inchar == '"') ||
                   (inchar == '(') || (inchar == ')') ||
                   (inchar == '&') || (inchar == '|') || (inchar == '~') ||
                   (inchar == ' ') || (inchar == ';') ||
                   (isprint(inchar) == 0) )
           { phase = 5; }
         else
           {
            phase = 9;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
        }
      else if (phase == 0)
        {
         if (isdigit(inchar))
           {
            digitFound = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
         else if (inchar == '.')
           {
            processFloat = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 1;
           }
         else if ((inchar == 'E') || (inchar == 'e'))
           {
            processFloat = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 2;
           }
         else if ( (inchar == '<') || (inchar == '"') ||
                   (inchar == '(') || (inchar == ')') ||
                   (inchar == '&') || (inchar == '|') || (inchar == '~') ||
                   (inchar == ' ') || (inchar == ';') ||
                   (isprint(inchar) == 0) )
           { phase = 5; }
         else
           {
            phase = 9;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
        }
      else if (phase == 1)
        {
         if (isdigit(inchar))
           {
            digitFound = CLIPS_TRUE;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
         else if ((inchar == 'E') || (inchar == 'e'))
           {
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 2;
           }
         else if ( (inchar == '<') || (inchar == '"') ||
                   (inchar == '(') || (inchar == ')') ||
                   (inchar == '&') || (inchar == '|') || (inchar == '~') ||
                   (inchar == ' ') || (inchar == ';') ||
                   (isprint(inchar) == 0) )
           { phase = 5; }
         else
           {
            phase = 9;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
        }
      else if (phase == 2)
        {
         if (isdigit(inchar))
           {
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 3;
           }
         else if ((inchar == '+') || (inchar == '-'))
           {
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
            phase = 3;
           }
         else if ( (inchar == '<') || (inchar == '"') ||
                   (inchar == '(') || (inchar == ')') ||
                   (inchar == '&') || (inchar == '|') || (inchar == '~') ||
                   (inchar == ' ') || (inchar == ';') ||
                   (isprint(inchar) == 0) )
           {
            digitFound = CLIPS_FALSE;
            phase = 5;
           }
         else
           {
            phase = 9;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
        }
      else if (phase == 3)
        {
         if (isdigit(inchar))
           {
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
         else if ( (inchar == '<') || (inchar == '"') ||
                   (inchar == '(') || (inchar == ')') ||
                   (inchar == '&') || (inchar == '|') || (inchar == '~') ||
                   (inchar == ' ') || (inchar == ';') ||
                   (isprint(inchar) == 0) )
           {
            if ((GlobalString[count-1] == '+') || (GlobalString[count-1] == '-'))
              { digitFound = CLIPS_FALSE; }
            phase = 5;
           }
         else
           {
            phase = 9;
            GlobalString = ExpandStringWithChar(inchar,GlobalString,&GlobalPos,&GlobalMax,GlobalMax+80);
            count++;
           }
        }

      if ((phase != 5) && (phase != 9))
        { inchar = GetcCLIPS(logicalName); }
     }

   if (phase == 9)
     {
      theToken->value = (VOID *) ScanSymbol(logicalName,count,&type);
      theToken->type = type;
      theToken->printForm = ValueToString(theToken->value);
      return;
     }

   /*=======================================*/
   /* Stuff last character back into buffer */
   /* and return the number.                */
   /*=======================================*/

   UngetcCLIPS(inchar,logicalName);

   if (! digitFound)
     {
      theToken->type = SYMBOL;
      theToken->value = (VOID *) AddSymbol(GlobalString);
      theToken->printForm = ValueToString(theToken->value);
      return;
     }

   if (processFloat)
     {
      fvalue = atof(GlobalString);
      theToken->type = FLOAT;
      theToken->value = (VOID *) AddDouble(fvalue);
      theToken->printForm = FloatToString(ValueToDouble(theToken->value));
     }
   else
     {
      lvalue = atol(GlobalString);
      if ((lvalue == LONG_MAX) || (lvalue == LONG_MIN))
        {
         PrintWarningID("SCANNER",1,CLIPS_FALSE);
         PrintCLIPS(WWARNING,"Over or underflow of long integer.\n");
        }
      theToken->type = INTEGER;
      theToken->value = (VOID *) AddLong(lvalue);
      theToken->printForm = LongIntegerToString(ValueToLong(theToken->value));
     }

   return;
  }

/***********************************************************/
/* CopyToken: Copies values of one token to another token. */
/***********************************************************/
globle VOID CopyToken(destination,source)
  struct token *destination, *source;
  {
   destination->type = source->type;
   destination->value = source->value;
   destination->printForm = source->printForm;
  }

/****************************************/
/* ResetLineCount: Resets the scanner's */
/*   line count to zero.                */
/****************************************/
globle VOID ResetLineCount()
  {
   LineCount = 0;
  }

/****************************************************/
/* GettLineCount: Returns the scanner's line count. */
/****************************************************/
globle long GetLineCount()
  {
   return(LineCount);
  }

/**********************************/
/* IncrementLineCount: Increments */
/*   the scanner's line count.    */
/**********************************/
globle VOID IncrementLineCount()
  {
   LineCount++;
  }

/**********************************/
/* DecrementLineCount: Decrements */
/*   the scanner's line count.    */
/**********************************/
globle VOID DecrementLineCount()
  {
   LineCount--;
  }