ldelim,rdelim
ldelim and rdelim are used for displaying the literal delimiter, in our case "{" or "}". The template engine always tries to interpret delimiters, so this is the way around that.
ldelim 和 rdelim 用于输出分隔符,也就是大括号 "{" 和 "}". 模板引擎总是尝试解释大括号内的内容,因此如果需要输出大括号,请使用此方法.