try to implement a compiler for PL/0 language in rust.
Inspired by Mashplant's decaf-rs project.
周计划: 11.19(第一周) 阅读java版本PL/0编译器的代码和文档, 了解PL/0语言的基本语法, 根据PL/0语言的特征,设计用rust实现PL/0编译器的架构(后续工作中可能修改此架构)
reference list
https://github.com/chyyuu/compiler_lab/tree/master/python2/pl0
https://github.com/chyyuu/compiler_lab/tree/master/rust/pl0
https://github.com/chyyuu/compiler_lab/tree/master/clang/pl0