参考https://www.cnblogs.com/praying/p/14457360.html https://zhuanlan.zhihu.com/p/342408254 （Rust过程宏入门（一）及后续）
https://dengjianping.github.io/2019/02/28/%E5%A6%82%E4%BD%95%E7%BC%96%E5%86%99%E4%B8%80%E4%B8%AA%E8%BF%87%E7%A8%8B%E5%AE%8F(proc-macro).html
1 写一个声明式宏（Declarative macros）add，main.rs：
macro_rules! add{ // macth like arm for macro ($a:expr,$b:expr)=>{ // macro expand to this code { // $a and $b will be templated using the value/variable provided to macro $a+$b } } } fn main(){ // call to macro, $a=1 and $b=2 println!("{}",add!(3,2)); }
2 过程宏有点麻烦，暂不写了