我在哪里可以学到编写 lexer 的基本知识？

我想学怎么写 Lexer。我的大学课程有一个作业，我们必须编写一个解析器(以及一个 lexer) ，但这是给我们没有任何指示或反馈(超出标准) ，所以我没有真正从中学到多少东西。

在搜索了这个主题之后，我只能找到相当高级的写作文章，它们集中在我感觉比我所处的领域领先几步的地方。我想讨论一下为一种非常简单的语言编写 lexer 的基础知识，我可以用它作为研究更复杂语言的标记的基础。

在这个阶段，我对最佳实践或优化技术并不感兴趣，相反，我更喜欢把重点放在要点上。有什么好的资源可以帮助我开始呢？

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最佳答案

Basically there are two main approaches to writing a lexer:

Creating a hand-written one in which case I recommend this small tutorial.
Using some lexer generator tools such as lex. In this case, I recommend reading the tutorials to the particular tool of choice.

Also I would like to recommend the Kaleidoscope tutorial from the LLVM documentation. It runs through the implementation of a simple language and in particular demonstrates how to write a small lexer. There is a C++ and an Objective Caml version of the tutorial.

The classical textbook on the subject is Compilers: Principles, Techniques, and Tools also known as the Dragon Book. However this probably falls under the category of "fairly advanced write ups".