Rust is another compiling language that may replace the position of C/C++ in server filed.
It runs fast and can be written easily comparing with Python/Go. Python is a dynamic language
and is limited in GIL, while Go is limited in its GC. That is reason why I prefer to learning Rust.
1.Rust macro:
If we add `!` affter a callee function, we call on a macro. And it is normal function when we call
without `!`.
println!("Hello World")
原文：http://www.cnblogs.com/zhuangzebo/p/7068185.html