code: public void setExprList(ExprList exprList) {
  		int len = exprList.length();
  		if (len == 0) {
  			throw new ParseException("模板函数名不能缺失", location);
  		}
  		
  		int index = 0;
  		Expr expr = exprList.getExpr(index);
  		if (expr instanceof Const && ((Const)expr).isBoolean()) {
  			if (len == 1) {
  				throw new ParseException("模板函数名不能缺失", location);
  			}
  			
  			nullSafe = ((Const)expr).getBoolean();
  			index++;
  		}
  		
  		funcNameExpr = exprList.getExpr(index++);
  		
  		ArrayList<Expr> list = new ArrayList<Expr>();
  		for (int i=index; i<len; i++) {
  			list.add(exprList.getExpr(i));
  		}
  		paraExpr = new ExprList(list);
  	}
docs: 是否支持函数名不存在时跳过