# 3A.4 语法分析工具

上文中讨论了如何对文法进行语法分析，并详细讨论了如何构造 LL 及 LR 文法的语法分析表（即上文中提到的预测表），但这只是为了深入理解语法分析的原理，在实践中的大多数情况下，我们都会直接使用语法分析器生成工具来直接生成语法分析器。因为在上述分析中我们可以发现一个事实：语法分析的总体流程是固定的，不同的仅仅是不同文法的语法分析表。而语法分析表的生成算法也是确定的，所以只要能够将文法的表示结构化，就可以将其作为输入，通过语法分析器生成工具直接生成一个语法分析器出来。Yacc(Yet Another Compiler-Compiler) 就是这样的一个工具。


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