code: private void scanFractionAndSuffix(int pos) {
          radix = 10;
          scanFraction(pos);
          if (reader.ch == 'f' || reader.ch == 'F') {
              reader.putChar(true);
              tk = TokenKind.FLOATLITERAL;
          } else {
              if (reader.ch == 'd' || reader.ch == 'D') {
                  reader.putChar(true);
              }
              tk = TokenKind.DOUBLELITERAL;
          }
      }
docs: Read fractional part and 'd' or 'f' suffix of floating point number.