Tiny脚本语言解释器

1. 安装

   • clone或下载仓库到本地， 用vs2019编译项目tiny和tiny_console

2. 使用

   • 运行tiny_console项目（C++实现的解释器） 或 运行python_tiny项目（python实现的解释器）
   • 运行后， 输入脚本语言允许的语句， 就会输出执行结果。C++版本会还会输出AST和翻译后的VM代码。

3. 示例

            i:=1; j:=1; repeat i:=i+1; j:=j+i until i=10; write j   
   

   • 输入上述代码， 虚拟机会计算1+2+3...+10并最后输出结果55

4. 词法

            _pattern = r'(?P<_0_white_space>[\s]+)|' \
                r'(?P<_0_newline>\n)|' \
                r'(?P<_1>if)|' \
                r'(?P<_2>then)|' \
                r'(?P<_3>else)|' \
                r'(?P<_4>end)|' \
                r'(?P<_5>repeat)|' \
                r'(?P<_6>until)|' \
                r'(?P<_7>read)|' \
                r'(?P<_8>write)|' \
                r'(?P<_101>[+])|' \
                r'(?P<_102>[-])|' \
                r'(?P<_103>[*])|' \
                r'(?P<_104>[/])|' \
                r'(?P<_105>[=])|' \
                r'(?P<_106>[<])|' \
                r'(?P<_107>[(])|' \
                r'(?P<_108>[)])|' \
                r'(?P<_109>[;])|' \
                r'(?P<_110>[:][=])|' \
                r'(?P<_201>[\d]+)|' \
                r'(?P<_202>[\w]+)|'
   

5. 语法

                program ->stmt_sequence
                
                stmt_sequence ->statement {';' statement}
                
                stmt ->if_stmt | repeat_stmt | assign_stmt | read_stmt | write_stmt
   
                stmt_if ->IF exp THEN stat_sequence [ELSE stmt-sequence] END
   
                stmt_repeat ->REPEAT stat_sequence UNTIL exp
   
                stmt_assign ->IDENTIFIER ':=' exp
   
                stmt_read ->READ identifier
   
                stmt_write ->WRITE exp
   
                exp ->simple_exp [COMPARISION_OP simple_exp]
   
                COMPARISION_OP ->'<' | '='
   
                simple_exp ->term {ADD_OP term}
   
                ADD_OP ->'+' |'-'
   
                term ->factor {MUL_OP factor}
   
                MUL_OP ->'*' | '/'
   
                factor ->'(' exp ')' | NUMBER | IDENTIFIER
   

6. 开发状态

   • 语法功能过于简单
   • 完全没有错误处理
   • 部分词法、语法设计不合理