用户输入一个文法，然后再输入，要被分析的字符串，自动进行语法分析，把每一不的分析过程都一一打印出来。直到分析成功或失败。-a user input grammar, and then imported to the string were analyzed automatically syntax analysis, the analysis of each process does not have to print out on January 1. Until the analysis of success or failure.