本项目为编译原理课程设计
输入语言为PASCAL
词法分析直接用了一个课本上给出的状态机，用if-elif实现。
使用递归下降的语法分析。没有生成AST，直接在语法分析的时候进行语义分析。
图形界面基于PyQt5
使用 Python 3.6 运行项目根目录下的 run.py 即可，请在运行前安装 PyQt5
This is a course exercice for Compiler Theory.
Accept a subset of PASCAL as input language.
Lexer uses a state machine given in the text book, implemented in "if-else".
Parse with RECURSIVE DOWN method, and AST is generated, SYMANTIC ANALYSIS is done while parsing.
GUI is PyQt5 based.
Run "run.py" in the root directory of this project in Python 3.6. Please install PyQt5 before running.