ANTLR flex/bison

https://stackoverflow.com/questions/29971097/how-to-create-ast-with-antlr4 这个很值得仔细看

https://github.com/alongubkin/modern/tree/master/compiler/ModernCompiler

https://www.jianshu.com/p/4bedad8dd70a

https://www.ibm.com/developerworks/cn/java/j-lo-antlr/index.html