由java编写的检验上下文无关语言是否为空的代码，可以处理嵌套形式，以$作为空串形式，大写字母作为非终结符。递归计算。形式语言与自动机的作业。-Written by the java test context-free languages is empty of code that can handle nested forms, to $ as the empty string form of capital letters as a non-terminator. Recursive com

java编写的上下文无关文法分析程序，图形界面，JBuilder运行环境，Eclipse也可，可以选择文件读取也可以自己输入。判断是否为空。形式语言与自动机的课程作业。-context-free grammar written in java parser, graphical interface, JBuilder runtime environment, Eclipse is also possible to select the file you can read their input.