该程序能求出任意给定的文法的所有非终极符和终极符的first集，所有非终极符的follow集，所有语句的select集，能求出能导空的非终极符集合。给定任意字符串该程序能判定出是否能接受。由于空符号不好输入，在程序中用到空符号全部用@表示。-The program can calculate any given grammar of all non-ultimate breaks and the ultimate symbol of the first set, all non-ultimate symbol of the follow set of the select set of all the statements can be derived to guide the ultimate symbol of non-empty set. Given an arbitrary string that the program can determine whether it can accept out. As the empty symbol bad input, an empty symbol used in the program all the available @ said.