自顶向下语法分析 实验报告 对于给定的源程序（如C语言或Pascal等），要求从组成源程序的字符行中寻找出单词，并给出它们的种别和属性——输出二元组序列。以便提供给语法分析的时候使用。要求能识别所有的关键字，标志符等，并且能够对出先的一些词法规则的错误进行必要的处理。-top-down syntax analysis report for the experiment to the source (such as C or Pascal, and other languages), request from the composition of source lines of the characters find words, and give them to other species and attributes -- output binary sequence. To provide for syntax analysis of the use. Requirements can identify all the keywords, URI. and right up to the first rule of lexical errors necessary treatment.