本文探讨了Lisp语言的起源和核心本质，特别是约翰·麦卡锡在1960年发表的具有里程碑意义的论文。麦卡锡通过引入简单的运算符和函数表示法，构建了一个完整的编程语言，并使用列表数据结构统一表示代码和数据。文章旨在帮助读者理解Lisp的核心思想，以及它为何与其他语言不同，并探讨编程语言的发展趋势，即从C模型向Lisp模型的转变。文章将使用Common Lisp代码复现麦卡锡的发现，揭示Lisp能够用自身语言描述的独特特性。

🤔 **麦卡锡的贡献：** 约翰·麦卡锡在1960年发表的论文，如同欧几里得之于几何，为编程领域奠定了基础。他证明了只需少量简单的运算符和函数表示法，就能构建一个完整的编程语言，即Lisp。

💡 **Lisp的核心思想：** Lisp语言的核心思想之一是使用列表数据结构统一表示代码和数据，这使得Lisp具有独特的灵活性和表达能力。

💻 **编程模型的演变：** 编程语言的发展经历了两个主要的模型：C模型和Lisp模型。随着计算机性能的提升，新的编程语言逐渐向Lisp模型靠拢，例如添加运行时类型检查和垃圾回收等特性。

📜 **Lisp的自描述性：** Lisp语言最显著的特点是它能够用自身语言描述，这源于麦卡锡的发现。文章通过复现麦卡锡的数学符号到Common Lisp代码的转换过程，解释了这一特性。

🎯 **Lisp语言的未来趋势：** Lisp模型代表了编程语言未来的发展方向，其灵活性和表达能力将继续影响着编程语言的设计和发展。

May 2001(I wrote this article to help myself understand exactlywhat McCarthy discovered. You don't need to know this stuffto program in Lisp, but it should be helpful to anyone who wants tounderstand the essence of Lisp — both in the sense of itsorigins and its semantic core. The fact that it has such a coreis one of Lisp's distinguishing features, and the reason why,unlike other languages, Lisp has dialects.)In 1960, John McCarthy published a remarkable paper inwhich he did for programming something like what Euclid did forgeometry. He showed how, given a handful of simpleoperators and a notation for functions, you canbuild a whole programming language.He called this language Lisp, for "List Processing,"because one of his key ideas was to use a simpledata structure called a list for bothcode and data.It's worth understanding what McCarthy discovered, notjust as a landmark in the history of computers, but asa model for what programming is tending to become inour own time. It seems to me that there have beentwo really clean, consistent models of programming sofar: the C model and the Lisp model.These two seem points of high ground, with swampy lowlandsbetween them. As computers have grown more powerful,the new languages being developed have been movingsteadily toward the Lisp model. A popular recipefor new programming languages in the past 20 years has been to take the C model of computing and add toit, piecemeal, parts taken from the Lisp model,like runtime typing and garbage collection.In this article I'm going to try to explain in thesimplest possible terms what McCarthy discovered.The point is not just to learn about an interestingtheoretical result someone figured out forty years ago,but to show where languages are heading.The unusual thing about Lisp — in fact, the definingquality of Lisp — is that it can be written initself. To understand what McCarthy meant by this,we're going to retrace his steps, with his mathematicalnotation translated into running Common Lisp code.