code: boolean lookForwardLineFeedAndEof() {
  		int forwardBak = forward;
  		int forwardRowBak = forwardRow;
  		for (char c=peek(); true; c=next()) {
  			if (CharTable.isBlank(c)) {
  				continue ;
  			}
  			if (c == '\n' || c == EOF) {
  				return true;
  			}
  			forward = forwardBak;
  			forwardRow = forwardRowBak;
  			return false;
  		}
  	}
docs: 向前看后续是否跟随的是空白 + 换行或者是空白 + EOF，是则表示当前指令后续没有其它有用内容