Since functions are the foundation of Lisp programs, the book begins with several chapters on functions.
The remainder of the book deals more with macros than functions. Macros receive more attention partly because there is more to say about them, and partly because they have not till now been adequately described in print.
form a complete tutorial on macro technique. By the end of it you will know most of what an experienced Lisp programmer knows about macros: how they work; how to define, test, and debug them; when to use macros and when not; the major types of macros; how to write programs which generate macro expansions; how macro style differs from Lisp style in general; and how to detect and cure each of the unique problems that afflict macros.
show some of the powerful abstrac- tions you can build with macros.
With Chapter 19 begins the fourth part of the book, devoted to embedded languages.
These programs are not short because they depend on programming tricks, but because they’re written using Lisp the way it’s meant to be used. The point of Chapters 23 and 24 is not how to implement ATNs in one page of code or Prolog in two, but to show that these programs, when given their most natural Lisp implementation, simply are that short. The embedded languages in the latter chapters provide a proof by example of the twin points with which I began: that Lisp is a natural language for bottom-up design, and that bottom-up design is a natural way to use Lisp.
The book concludes with a discussion of object-oriented programming, and particularly CLOS, the Common Lisp Object System. By saving this topic till last, we see more clearly the way in which object-oriented programming is an extension of ideas already present in Lisp. It is one of the many abstractions that can be built on Lisp.
A chapter’s worth of notes begins on page 387. The notes contain references, additional or alternative code, or descriptions of aspects of Lisp not directly related to the point at hand. Notes are indicated by a small circle in the outside margin. There is also an Appendix (page 381) on packages.