写一个能识别for循环语句的文法，通过一定的变换使它符合文法的要求，然后按照这个文法编写一个程序，该程序能识别输入的语句是否符合for语句的文法，或者能不能通过文法的开始符号推导出该语句-Write a for loop to identify the grammar, through some transformation to make it consistent with　the requirements of grammar, and then follow the grammar to write a program that can identify whether the input statement for statement, grammar, or can grammar symbols by the beginning of the statement is derived