语法分析是编译过程的一个逻辑阶段。语法分析的任务是在词法分析的基础上将单词序列组合成各类语法短语，如“程序”，“语句”，“表达式”等等.语法分析程序判断源程序在结构上是否正确.源程序的结构由上下文无关文法描述.语法分析程序可以用YACC等工具自动生成。-Grammar analysis is a logical compile process stage. The task of grammatical analysis is in a separate lexical analysis on the basis of the combination of all kinds of grammar words sequence into phrases, such as "program", "statements", "expression" and so on. Grammar analysis program judgment in the structure of the source program is correct. The structure of the source program by context-free grammar descr iption. Grammar analysis program can use YACC tools such as automatic generation