通过设计、编制、调试一个布尔表达式的语法及语义分析程序，加深对语法及语义分析原理的理解，并实现词法分析程序对单词序列的词法检查和分析。-By designing, developing, debugging a boolean expression syntax and semantic analysis procedures, better understanding of the syntax and semantic analysis of understanding of the principles and procedures to achieve lexical analysis of the lexical word sequence inspection and analysis.