js实现一个简单的编译器
参考链接：
https://zhuanlan.zhihu.com/p/31096468
https://github.com/jamiebuilds/the-super-tiny-compiler
https://github.com/starkwang/the-super-tiny-compiler-cn/blob/master/super-tiny-compiler-chinese.js
https://blog.csdn.net/qiansg123/article/details/80131921